Frequently Asked Questions

Del Sur Elementary Remediation – Community Update (October 19, 2026)

Poway Unified is nearing completion of its investigation into the underlying causes of mold growth at Del Sur Elementary. In consultation with environmental consultants, mechanical engineers, and architects, staff is recommending additional remediation and a new heating, ventilation, and air conditioning (HVAC) system to address the campus's moisture and humidity concerns. In order to prepare for a proposed plan to install new HVAC equipment, staff will issue a request for proposals (RFP) in the coming days.

Staff and district consultants will brief the Board on conditions and recommendations at the Board's regular meeting on Thursday, November 5. At that meeting, staff will present the investigation findings, discuss the range of options possible for a permanent fix to the issue, and will request authorization to proceed with design and installation of a new system. The Board meeting will be at 6:00 p.m. in the Community Room of the District Office (15250 Avenue of Science, San Diego, 92128).

Based on what we know today, the installation of a new HVAC system at Del Sur will extend the timeline for students and staff at Stone Ranch until summer 2027; a more detailed timeline will be shared on November 5. Staff will also schedule a community information meeting for families and staff with participation from environmental, mechanical, and architectural experts in the near future. As soon as that is scheduled, we will let you know.

What has changed since the previous update?

The earlier plan focused on repairing and optimizing the existing HVAC system, improving humidity control, replacing affected finishes, and evaluating the results before reopening. At that time, the professional assessment was that the existing system could serve the campus with modifications and a consistent operating protocol. Further investigation and testing were part of that plan.

As demolition and more detailed inspections progressed, additional concerns became visible. SOCOTEC US conducted an independent mold and moisture assessment of the main building and two portable buildings between September 30 and October 8. Environmental testing reports will be finalized in the near future and will be shared as soon as they are available. The assessment identified microbial growth on chilled-water pipe insulation in portions of the first floor, water staining on pipe insulation throughout the buildings, and elevated moisture in selected mechanical closets and the maintenance room. Positively, there is no evidence of Stachybotrys chartarum, also commonly known as “black mold.”

These findings, together with the campus's history of temperature and humidity challenges, have informed the recommendation for a more extensive mechanical-system upgrade. Removing and replacing the affected insulation would address its current condition but would not, by itself, resolve the broader concern about recurring moisture.

What work has been completed?

The initial response included cleaning and antimicrobial treatment, dehumidification, air filtration, HVAC and duct cleaning, and environmental sampling. Follow-up testing identified areas requiring additional attention, leading to the relocation of students and staff while investigation and corrective work continued.

Since then, crews have removed existing flooring and selected wall and ceiling materials, moved and documented classroom contents, and supported detailed mechanical and environmental inspections. The District has engaged environmental consultants, architects, engineers, and contractors to evaluate conditions and develop the next phase of work.

What is proposed next?

The proposed work has three coordinated parts:

Additional removal and restoration. Remove existing chilled-water piping and insulation, classroom air-handling units, and other identified materials. Install flooring, ceiling tiles, wall panels, and other finishes with durable materials that are appropriate for school use and easier to maintain.
Environmental cleaning and clearance. Address identified moisture sources, clean hard surfaces and ductwork, and sanitize salvageable contents. Conduct environmental clearance testing following remediation and before reinstalling finishes.
A new HVAC system with humidity control. Remove the existing chilled-water cooling approach and install a refrigerant-based system. The proposed design includes new equipment serving classrooms, conditioning for interior hallways, and humidity control that removes moisture while maintaining comfortable temperatures. Rooftop equipment will require associated structural improvements.

What is the revised timeline?

The proposed schedule includes design work this fall, submission to the Division of the State Architect in December 2026-January 2027, targeted approval in February, and construction from March through June. This will be reviewed and finalized at the November 5, 2026, Board meeting. The proposed project schedule identifies July 9, 2027, as the target for building occupancy. This is a planning target and remains dependent on approvals, equipment delivery, construction, system performance, and environmental clearance.

Completion of construction alone will not determine readiness. The District will rely on professional evaluation of the completed work and environmental conditions before students and staff return. Any unresolved concerns will require further corrective work and evaluation.

How will the District continue to support both Del Sur and Stone Ranch school communities?

District staff continue to work with both principals to address the needs of Del Sur and Stone Ranch staff and students. This includes supervision, support-service space, outdoor shelter, bell schedules, staff collaboration, and additional wear on the campus; the District will also support Del Sur by ensuring that all curriculum materials and other resources are available to students and teachers. Staff will also request Board authorization for additional portable space for support services.

The District is pursuing insurance coverage and state facility hardship funding and evaluating other available funding sources. Further information about project costs and funding will be shared as the scope and estimates are refined.

We will continue to share substantive findings, finalized environmental reports, and schedule updates through school and district communications. Our commitment is to explain what we learn, how it changes the work, and what must be completed before the Del Sur community returns home.

Community Update (September 4, 2026)

Del Sur Elementary Remediation – Community Update (September 4, 2026)

The District is now targeting January 2027 for Del Sur students and staff to return to the Del Sur campus. This timeline reflects the full sequence of work required: sourcing specialized materials and equipment; completing necessary modifications and installation; testing, balancing, and commissioning the systems to optimize performance; assessing their performance under normal operating conditions; conducting follow-up environmental testing; allowing time for laboratory analysis and professional review; and preparing classrooms and moving staff and students back to campus.

January is a planning target, not a deadline that will override the work. If the evaluation, repairs, system commissioning, or follow-up testing identifies additional work, the District will complete that work and adjust the timeline accordingly. We will not reopen the campus simply to meet a projected return date.

If this process can be completed sooner and the results support re-occupancy, we will return sooner. Our commitment remains unchanged: students and staff will return only after the necessary work is complete, follow-up testing has been conducted and professionally reviewed, and objective evidence demonstrates that the campus is ready to safely support them.

We recognize that this extends the temporary relocation beyond what was initially anticipated. As the campus evaluation has progressed, however, we are gaining a clearer understanding of the work necessary to address the underlying moisture and humidity conditions comprehensively rather than pursue another short-term solution.

Root-Cause Analysis and Industrial Hygienist's Report

The root-cause analysis is being conducted by a multidisciplinary team that includes District facilities staff, mechanical engineers, architects, building automation and controls specialists, an independent industrial hygienist, contractors, and other technical experts.

The team is evaluating the campus as an interconnected system, including heating, ventilation, and air conditioning (HVAC) equipment and controls, airflow, drainage, building materials, moisture and humidity conditions, and other potential contributing factors, rather than examining any one component in isolation.

The industrial hygienist's final assessment, dated August 28, is now available at this link. It follows the preliminary results shared with families on August 23. The underlying test results have not changed; the final report provides additional analysis, context, and recommendations.

Among those recommendations, the industrial hygienist called for a comprehensive evaluation of the HVAC system to determine the most effective way to manage humidity throughout the campus. The report also recommends that a mechanical engineer establish a schoolwide operating protocol so that heating, cooling, ventilation, and humidity control work together consistently across the campus.

The current professional assessment is that the HVAC system can adequately serve the campus if modifications are completed and a consistent schoolwide operating protocol is established. Our investigation will continue.

The team will continue to validate that conclusion through system commissioning, performance assessment, and follow-up environmental testing. If that work indicates that additional modifications, repairs, upgrades, or replacement of particular components are necessary, the District will complete them before reopening.

The industrial hygienist also recommends that, after any necessary modifications are complete, the HVAC system operate under normal school-year conditions for at least 48 hours before another round of air sampling is conducted. This will allow the District to evaluate environmental conditions while the mechanical system is operating as it will when students and staff are present.

The decision to reoccupy the campus will be informed by the mechanical engineers' evaluation of system performance and the independent industrial hygienist's review of post-work environmental conditions. If follow-up testing or system evaluation identifies an unresolved concern, the affected area will not return to use. Additional corrective work will be completed, and the area will be evaluated and tested again before it is occupied.

Major Renovation Work Underway

The District is moving forward with substantial work at Del Sur during the remainder of the year. The following provides an overview of the work planned through December 2026.

Flooring and Interior Improvements

Existing carpet is being removed throughout the campus.
Replacement flooring and selected interior finishes will be installed.
Furniture and classroom contents are being carefully moved, documented, and stored while work is underway.
The goal is not simply to replace what was removed, but to install durable, school appropriate finishes and provide refreshed learning spaces for students and staff.

HVAC Evaluation, Repairs, and Optimization

Interior and rooftop air-handling units, air-conditioning systems, and supply and exhaust fans are being inspected, cleaned, serviced, and repaired where needed.
The inspections include drainage systems, insulation, valves, motors, fans, ductwork, electrical connections, filters, and other mechanical components.
The chiller plant and boiler room are also being evaluated and will be serviced based on the findings of the mechanical engineers.
Engineers will establish a coordinated schoolwide operating protocol designed to improve humidity management and ensure the various components of the HVAC system operate effectively together.
After any necessary modifications are completed, the HVAC system will undergo testing, balancing, and commissioning. This process will verify that individual components are operating properly together, that airflow is appropriate throughout the campus, and that the system can manage temperature and humidity under normal operating conditions.

Humidity Control

Engineers are developing both interim and permanent solutions to improve humidity control within the two-story building, including the interior hallway.
An interim humidity-control solution will be installed and evaluated before students and staff return.
Humidity conditions will continue to be monitored as the HVAC system is repaired, optimized, and tested.
The District will continue humidity monitoring after the campus reopens. Engineers will review system performance and environmental conditions to confirm that the improvements continue to operate as intended and to identify any condition requiring adjustment or additional action.

Requirements for Returning to Campus

Before students and staff return, the District expects to complete the following:

Renovations and humidity-control improvements
Testing, balancing, and commissioning of the HVAC system
Operation of the system under normal school-year conditions
Follow-up environmental sampling and professional review of the results
Any additional corrective work identified through that process
Preparation and inspection of classrooms and common areas
A coordinated move-in process for staff and students

The District is currently targeting December 2026 for completion of the major flooring, interior, HVAC, and interim humidity-control work necessary to support a January return. Completion of construction alone will not determine the return date. The upgraded systems must be evaluated under normal operating conditions, follow-up environmental testing must be completed and reviewed, and any additional concerns must be addressed before the campus is reoccupied.

Additional Updates

Portable classrooms at Stone Ranch: The new portable classrooms will be ready for students and staff beginning Tuesday, September 8, 2026.
Continued transparency: District will continue to share final environmental reports and substantive findings with families and staff as they become available, along with clear explanations of what the findings mean and how they are informing the work.

We appreciate the continued patience and flexibility of the Del Sur and Stone Ranch communities. We understand that families and staff want confidence not only that the work will be completed, but that it will be done thoroughly and correctly. That is also our expectation.

We will continue to provide meaningful updates as the work progresses. If the work, system evaluation, and follow-up testing support an earlier return, we will communicate that opportunity promptly. Verified readiness, not the calendar, will determine when students and staff return to Del Sur.

Evening Updates - Daily summary of progress, new information, and FAQ updates

Evening Update - Friday, August 28

Progress Made:

Additional portable classrooms arrived at Stone Ranch as planned. Electrical crews are now running wiring through the conduit to provide power to the new buildings as installation work continues.

Next Steps:

As operations at Stone Ranch continue to stabilize and the work at Del Sur moves into a longer-term evaluation phase, this will be our final scheduled daily Evening Update. Going forward, we will provide updates when there is meaningful new information to share, including developments related to the root-cause analysis, environmental testing, corrective work, and more.
You can expect to hear from us at the end of next week with an update on the anticipated return to Del Sur; we’ll communicate sooner if we have meaningful information before that.
We are also working closely with Principal Ganesan, and families may receive relevant updates directly from the school as information relates to day-to-day operations at Stone Ranch.

Evening Update - Thursday, August 27

Progress made:

We’re excited to share that delivery of the new portable classrooms is underway! Three classrooms were successfully delivered between last night and this morning.

Next steps:

Delivery will continue over the next several days:

Tonight: One additional classroom is scheduled to arrive.
Tomorrow morning: One additional classroom is scheduled to arrive.
Monday, August 31: The remaining two classrooms are currently scheduled for morning delivery.

We appreciate everyone’s patience and flexibility as deliveries continue and the new classrooms begin to take shape on campus.

Evening Update - Wednesday, August 26

Progress made:

A multidisciplinary team walked the Del Sur campus as part of the root-cause analysis. The group included District staff, mechanical engineers, architects, system software engineers, and other specialists to evaluate building systems, moisture and humidity conditions, and investigate potential contributing factors.
The fencing and asphalt installation for the portable classrooms at Stone Ranch is complete. We are happy to share that the delivery and installation of the portables is anticipated to begin this evening, earlier than originally projected.
The link is now available for the family information session.

Next steps:

Additional information will be provided to staff regarding the upcoming Del Sur carpet removal, including timelines, access to classrooms and workspaces, and any potential impacts on personal and instructional belongings.
We will continue providing responses to questions submitted during the Family Information Session. Many have since been addressed through recent updates and the FAQ, but additional responses are still being prepared. Once we have final assessments and substantial information from the root cause analysis we will hold the follow-up family information session.

Evening Update - Tuesday, August 25

A special thank you to the Stone Ranch Elementary Staff and Foundation, who collaborated to help make the first days at Stone Ranch feel welcoming by providing breakfast and lunch, and assembling classroom supply kits. We also appreciate Assemblymember Dr. Darshana Patel’s team as well as volunteers from the Kiwanis for being present to support students, staff, and families and help provide a warm welcome.

And a special thank you to Principal Teri Heard and the Stone Ranch team for their leadership, flexibility, and partnership in welcoming the Del Sur community.

Progress made:

Moisture-control equipment continues to operate at Del Sur as monitoring and evaluation work continues.

Next steps:

The decision was made to replace all carpet throughout the school with tile.
Tomorrow, August 26, a multidisciplinary team will walk the Del Sur campus as part of the root-cause analysis. The group will include District staff, mechanical engineers, architects, system software engineers, and other specialists working together to evaluate building systems, moisture and humidity conditions, and potential contributing factors.
Portable classroom buildings are on their way to Stone Ranch to provide additional space and support for our school communities. Beginning this afternoon, Facilities Design and Construction will cone off a portion of the lower parking lot. Temporary fencing and asphalt preparation will begin Wednesday, with the portable buildings expected to arrive later this week. Because of transportation and curfew restrictions, delivery will occur during the early morning hours.

Evening Update - Monday, August 24

Today was a great first day of school for Del Sur!

While there are still a few details to fine-tune as everyone settles into the temporary campus, today was a very positive start for students and staff.
Additional portable classrooms are being brought in to further support the Del Sur program during the temporary relocation. We expect these portable classrooms to arrive by September 8, 2026. The following classes will be assigned to the portables: Campos, J. Richards, Schofield, Lovoda, A. Richards, and Miller. Principal Ganesan will provide more detailed updates to these classes as soon as the details have been finalized.

Work at Del Sur continues:

Facilities, Maintenance & Operations met today to continue planning the next phase of the root-cause analysis at Del Sur. This work is focused on moving beyond short-term remediation and understanding the conditions that allowed the moisture and humidity concerns to develop in the first place, so a permanent fix can be implemented.
The District and its professional contractors are developing a more comprehensive evaluation of the campus, including potential contributing factors such as indoor humidity and moisture levels, HVAC operation and humidity control, mechanical systems and equipment, possible water intrusion, and whether materials adequately dried following summer carpet cleaning or other maintenance activities.
The goal is not another temporary fix. The District is working to identify the underlying cause or combination of causes, determine what corrective work is needed to address those conditions over the long term, and establish how the effectiveness of that work will be verified. These findings will inform the corrective action plan and the conditions that must be met before students and staff return to Del Sur.

We will continue to provide updates as that work progresses.

Evening Update - Sunday, August 23

Progress made:

A huge thank you to our Educational Technology and Technology Support Services teams for helping prepare classrooms, devices, systems, and instructional spaces for tomorrow.
Special thanks to Teri Heard, Principal of Stone Ranch Elementary, for her leadership, partnership, and support in welcoming the Del Sur community.

We are excited to welcome your students to their first day of school tomorrow at Stone Ranch Elementary.

In keeping with our commitment to provide families with environmental testing information as it becomes available, we are sharing the following documents:

These documents provide additional detail about the testing results, historical context, and the work that will continue while students are temporarily located at Stone Ranch. These documents are also publicly posted on this page.

Evening Update - Saturday, August 22, 2026

Progress made:

Del Sur staff were joined and supported by Elementary Principals from across the district at Stone Ranch to continue to prepare for the opening day of school.
Staff from Facilities Maintenance & Operations, Planning, Construction, Custodial, Purchasing, Warehouse, and Nutrition Services were also providing logistical support.

The work to understand why the moisture and mold conditions developed is still underway. The District and its professional contractors are continuing to investigate possible contributing factors, including (but not limited to):

Indoor humidity and moisture levels;
HVAC operation and humidity control;
Mechanical systems and equipment;
Carpet cleaning and whether materials adequately dried afterward;
Possible water intrusion through the building envelope;
Plumbing leaks or broken pipes;
Moisture beneath carpet, in walls, or in other building materials; and
Other conditions that could have introduced or retained moisture.

At this point, we have not confirmed a single root cause. It is also possible that more than one factor contributed. We will continue that investigation until we understand what occurred and what corrective actions are necessary to reduce the likelihood of recurrence.

Tomorrow, Sunday, August 23, we will be providing the Industrial Hygienist’s reports. These are the results from the testing completed on Sunday, August 9, which informed the District's decision to delay the start of the school year. Also included are the results from the testing completed on August 12 and 16, which informed the District’s decision to relocate Del Sur students and staff.

What testing results will the District share with families tomorrow?

Tomorrow we will share the written reports from the environmental testing that informed the District's decision to delay the start of school and temporarily relocate Del Sur students and staff.

Because the preliminary laboratory data require professional interpretation, the District will publicly share the results once the updated reports, cover sheet, and Industrial Hygienist’s assessment are complete. The anticipated publication date is tomorrow, Sunday, August 22.

Will the final reports identify the types of mold that were detected?

Yes. The laboratory testing identifies categories of airborne mold spores. Our preliminary information indicates the primary types of mold identified in the affected rooms were Penicillium/Aspergillus-type and Cladosporium spores.

How is the District deciding whether Del Sur can be reoccupied?

There is no single government mold-spore number that automatically determines whether a school or classroom can be occupied.

The District is relying on independent professional evaluation that considers laboratory results together with visual observations, moisture conditions, mold odor, building materials, the source of moisture and the remediation work that has been completed.

Affected areas will not return to normal use until the necessary work is complete and the industrial hygienist has evaluated the conditions and provided an appropriate recommendation regarding re-occupancy.

Is there a legal mold limit for classrooms?

No. EPA and California public-health guidance do not establish a numerical airborne-mold exposure limit for schools.

Instead, guidance focuses on identifying and correcting moisture problems, addressing visible mold and affected materials, eliminating persistent mold odor, drying materials and verifying that corrective work has been effective.

What can the testing tell us about past exposure?

Environmental air samples provide information about conditions during the time the samples were collected.

They do not reconstruct what was present in a classroom on every earlier date, calculate an individual person's cumulative exposure, or determine whether a specific person experienced a health effect.

What health effects can mold and dampness cause?

CDC/NIOSH identifies associations between damp indoor environments and respiratory symptoms, development or worsening of asthma, respiratory infections, allergic rhinitis, bronchitis, eczema and, more rarely, hypersensitivity pneumonitis.

Many people may experience no symptoms, while individuals with asthma, allergies or other sensitivities may be more susceptible. A laboratory spore count cannot predict an individual health outcome.

What should I do if my student or I have symptoms?

Consult your healthcare provider for medical advice. Employees should report workplace concerns to their supervisor.

Why was Del Sur relocated?

The decision to relocate was made because the environmental testing showed that additional remediation and evaluation were necessary and that the problem had not been fully resolved.

Tomorrow's finalized reports are the reports associated with that decision. They will provide families and staff with the updated testing information and professional interpretation that informed the relocation.

Why didn't the first round of remediation solve the problem?

The initial remediation addressed conditions that had been identified at that point. The subsequent environmental testing showed that additional work was necessary.

That is why the District did not treat completion of the first round of cleaning/remediation as the end of the process. The testing prompted the decision to relocate students and staff while additional remediation and investigation continued.

What happens before students and staff return to Del Sur?

Before affected areas return to normal use, the underlying moisture conditions must be sufficiently understood and addressed, affected materials must be appropriately cleaned, removed or repaired, the space must be dry and free of unresolved visible mold or mold odor, and the industrial hygienist must evaluate the completed work.

The District will use the professional assessment and any required follow-up testing to determine when the campus is appropriate for re-occupancy.

Will there be additional testing?

Yes. Additional testing and monitoring will be conducted as appropriate following remediation and as recommended by the industrial hygienist.

That information will be part of the District's determination about when affected areas can return to normal use and how conditions should be monitored afterward.

Evening Update - Friday, August 21, 2026

Progress Made

Del Sur teachers and staff began setting up their instructional spaces at Stone Ranch today.
Where needed, surplus furniture was delivered from other school sites to prepare classrooms. No furniture was moved from Del Sur.
Classroom sets of instructional materials were delivered from the District’s central bookroom, providing teachers with the core resources they need to begin the school year.
Campus security has been assigned to the Boys & Girls Club location. Please know that the building is secure, and visitors must be buzzed in. Parents will continue to check students in and out through the main office. Students assigned to these classrooms will still eat lunch and have recess with their grade-level peers at Stone Ranch. These classes will still do arrival and pick-up on the blacktop at Stone Ranch. Teachers will take them to and from the Boys and Girls Club.
Dismissal and ESS - After school procedures

Next Steps

A custodial crew will be at Stone Ranch tomorrow to complete final preparations and ensure classrooms and shared spaces are ready for students on Monday.

Del Sur and Stone Ranch teachers and staff are ready and excited to welcome students to campus.

We know this has been an unusual path to the first day of school, and we appreciate the flexibility and patience of our families and staff. We are looking forward to welcoming Del Sur students to Stone Ranch on Monday and getting the school year underway.

Evening Update - Thursday, August 20, 2026

Progress made:

District teams continued procuring classroom and instructional supplies needed for the temporary relocation to Stone Ranch Elementary.
Staff are continuing to prepare instructional spaces and operational support for Monday.

Updates on the transition to Stone Ranch:

Detailed school schedules, including arrival, dismissal, recess, and lunch information, will be sent to families tomorrow. Additional transition information will be shared as logistics are finalized.

The following questions have also been added on the FAQ page.

What were the ESS room assignments during the summer of 2026?
Why haven’t we seen the final reports from the most recent round of independent testing?
Will the district host another Family Information Night before reopening Del Sur?

Evening Update - Wednesday, August 19, 2026

Dear Del Sur Families,

Thank you to those of you who were able to attend tonight’s meeting. The recording will be available soon. We also collected several questions which will be reviewed and addressed as information becomes available.

One major update after tonight’s meeting is that we will not be moving materials from Del Sur to Stone Ranch. We recognize that most classrooms at Del Sur have returned results in the acceptable range. At the same time, we have heard concerns from members of our community at tonight’s information session about moving materials between campuses. To provide greater confidence in the transition and simplify the move, we will start at Stone Ranch with new instructional and classroom supplies rather than relocating materials from Del Sur.

Thank you for your ongoing support and partnership.

Sincerely,

Jennie Ganesan, Principal

Ben Churchill, Superintendent

Evening Update - Tuesday, August 18

We received and reviewed the latest post-remediation testing results today. Based on those results and consultation with our independent environmental professionals, we have made an important decision about the start of the school year.

Results Overview

The majority of the areas tested following remediation returned results in the acceptable range. A small number of areas require additional attention:

Moderate (moderate probability of mold spores originating from indoors): Rooms 124, 126, 133, and 147; the Multi-Purpose Room; and the first-floor hallway.

In Room 126, the finding was identified above the ceiling tiles.

Elevated (high probability of mold spores originating from indoors): No areas tested in the elevated range.

Remediation and moisture-control equipment will continue operating on campus while additional work, investigation, and evaluation take place.

Reopening Plan

After reviewing the results with our independent environmental professionals, school and district leadership, and labor partners, we have decided to temporarily relocate the entire Del Sur Elementary School community to Stone Ranch Elementary School for approximately one month.

First day for Del Sur students at Stone Ranch: Monday, August 24
Temporary relocation: August 24 through September 18
Anticipated return to Del Sur: Monday, September 21

Although most of the areas tested at Del Sur are now in the acceptable range, we do not want to approach the remaining concerns with another temporary solution. Temporarily relocating the school gives us the time and full access to the campus needed to continue investigating the broader moisture and humidity conditions, complete additional corrective work, and pursue a more permanent solution without repeatedly disrupting students and staff.

During the relocation period:

Environmental and moisture-control equipment will continue operating at Del Sur.
The District will work with architects, mechanical engineers, HVAC technicians, environmental professionals, and other specialists to further investigate the source of the elevated moisture conditions, identify the root cause of the ongoing issues, and determine appropriate long-term corrective measures.
Environmental testing and monitoring will continue as the work progresses.

We recognize that temporarily relocating an entire school creates significant logistical questions for families and staff. We are finalizing those details now, including arrival and dismissal, ESS, preschool, classroom assignments, meals, and other day-to-day operations. We will share that information as soon as it is finalized and will continue providing regular updates throughout the temporary relocation.

Family Information Session

We will hold our scheduled Family Information Session at the Del Norte High School Performing Arts Center on Wednesday, August 19, at 6:30 p.m.

The session will provide an opportunity to share more information about the remediation work, environmental testing and results, the decision to temporarily relocate, and our plans for addressing the remaining concerns at Del Sur. We will also provide additional information about the start of the school year for Del Sur students at Stone Ranch Elementary and answer questions from families.

We will record the session and make it available online for families who are unable to attend.

We know this is another significant change for Del Sur families, students, and staff. While relocating the school is disruptive, we believe it provides the best path forward: students can begin school while we give the Del Sur campus the time, access, and attention necessary to pursue a lasting solution to the moisture issues.

Evening Update - Monday, August 17

Crews continued remediation work throughout the Del Sur campus today.

Remediation work is complete.
Dehumidifier units which will remain in classrooms have arrived.

What happens next?

Based on the current schedule:

We expect to receive and review initial testing results tomorrow, Tuesday, August 18. We will use those results, along with the independent industrial hygienist's evaluation, to determine whether the identified issues have been appropriately addressed. Once initial results are received and reviewed, we will share the findings and confirm next steps for reopening.
If the results confirm that the necessary remediation has been successfully completed, teachers and staff will return on Wednesday, August 19, to prepare classrooms, and school will reopen for students on Thursday, August 20.

Alternate Reopening Plan

The District has developed an alternate reopening plan so we are prepared if the testing results show that some or all areas of the Del Sur campus require additional work.

Depending on the results, the plan may include temporarily relocating a small number of classrooms, certain grade levels, or the full school to an alternate school site. District teams are working with our labor partners and other departments on the logistics needed to support each scenario.

We will share the specific reopening plan as soon as the testing results are reviewed and a decision is made.

Family Information Session

The session will provide an opportunity to share more information about the remediation work, environmental testing and results, ongoing monitoring, and next steps, as well as answer questions from families.

Date: Wednesday, August 19, 2026
Time: 6:30 p.m.
Location: Del Norte High School - Performing Arts Center

We will record the session and make it available online for families who are unable to attend. We will confirm the date, time, location, and other details once we have reviewed the testing results and can confirm the reopening plan.

Thank you for your continued patience as we complete this work carefully and thoroughly. We will provide another update tomorrow evening.

Updated FAQs

We have added the information above and additional information to the FAQ page. The new questions and answers are both copied here:

Will the complete testing reports be shared, and what is included in the clearance testing?

Yes. We expect to receive an initial evaluation from the independent industrial hygienist on Tuesday, August 18, which will help determine whether the remediated spaces are ready for re-occupancy. The complete testing reports will be made publicly available once they are finalized and provided to the District.

The post-remediation clearance process is designed to evaluate both the air and surfaces in the areas that were treated. Testing may include:

Air sampling: Indoor air is collected and analyzed for airborne mold spores and compared with outdoor control samples.
Surface sampling: Tape-lift samples are collected from selected surfaces, such as carpet, walls, windowsills, or other areas of concern, to determine whether active mold growth remains.
Additional material sampling, when appropriate: In some areas, wall-core or other targeted sampling may be used to evaluate conditions that cannot be assessed through air or surface testing alone.
Visual and environmental evaluation: The industrial hygienist reviews the condition of the space, including moisture and humidity conditions, alongside the laboratory results.

The independent industrial hygienist will use these findings to determine whether the identified issues have been appropriately addressed or whether additional remediation or testing is needed before a space returns to normal use.

Evening Update - Sunday, August 16

Crews continued remediation work throughout the Del Sur campus today.

All remaining HVAC and carpet cleaning in common areas was completed this evening, including HEPA vacuuming and wet wiping of hard surfaces.
The independent industrial hygienist completed post-remediation sampling in the areas where remediation work has been completed.

As remediation and testing continue, we ask that families and community members not enter the campus unless specifically authorized. Del Sur remains an active work site, and unauthorized access can interrupt remediation activities, disturb containment measures or equipment, and potentially delay the work and testing necessary to reopen the campus.

What happens next?

Based on the current schedule:

Belfor will return tomorrow, Monday, August 17, to monitor dehumidifiers and supplemental air-conditioning equipment and complete any remaining miscellaneous work.
The independent industrial hygienist will also return Monday to complete post-remediation sampling in the library, Multi-Purpose Room (MPR), and Room 127.
We expect to receive and review initial testing results on Tuesday, August 18. We will use those results, along with the independent industrial hygienist's evaluation, to determine whether the identified issues have been appropriately addressed. Once initial results are received and reviewed, we will share the findings and confirm next steps for reopening.
If the results confirm that the necessary remediation has been successfully completed, teachers and staff will return on Wednesday, August 19, to prepare classrooms, and school will reopen for students on Thursday, August 20.
If the results indicate that additional work is needed, we will communicate that information and any changes to the reopening timeline as soon as possible.

We are also developing an alternate reopening plan so that we are prepared if portions of the campus require additional work. On Monday, we will finalize and share that plan, including options for a partial reopening if the entire campus is not yet ready for occupancy.

Family Information Session

We are planning an in-person family information session before students return to campus, tentatively on Wednesday evening. The session will provide an opportunity to share more information about the remediation work, environmental testing and results, ongoing monitoring, and next steps, as well as answer questions from families.

Thank you for your continued patience as we complete this work carefully and thoroughly. We will provide another update tomorrow evening.

Evening Update - Saturday, August 15

Crews continued working throughout the campus today.

Crews completed HEPA vacuuming and wet wiping in all classrooms.
HVAC system cleaning and carpet cleaning were also completed in all classrooms.
Crews also began work in the library, Multi-Purpose Room (MPR), administrative offices, and staff spaces.

Based on the current schedule:

Remediation work in the library, Multi-Purpose Room (MPR), and office areas is expected to be completed tomorrow, Sunday, August 16.
Tomorrow crews will complete final cleaning of the first- and second-floor hallways. This will allow the independent industrial hygienist to begin post-remediation sampling.
As soon as those results are available and reviewed, we will share the next update and confirm our reopening timeline.

Evening Update - Friday, August 14

Crews continued working throughout the campus today. Based on the current schedule:

Remediation work in all classrooms is expected to be completed by the end of the day tomorrow, Saturday, August 15.
Remediation work in the library, Multi-Purpose Room (MPR), and office areas is expected to be completed on Sunday, August 16.

An independent third-party industrial hygienist will conduct comprehensive post-remediation environmental testing on Sunday, August 16. Testing will include air sampling, surface tape-lift sampling, and wall-core sampling and is expected to take the full day.

We now expect to receive and review the initial testing results on Tuesday, August 18. We will use those results to determine whether the identified issues have been appropriately addressed and to confirm that the campus is ready for students and staff to return.

If the results confirm that the necessary remediation has been successfully completed, teachers and staff will return on Wednesday, August 19, to prepare their classrooms, and school will reopen for students on Thursday, August 20. If additional work is needed, we will communicate that information and an updated timeline as soon as possible.

We also plan to hold an in-person family information session before students return to campus, tentatively on Wednesday evening. The session will provide an opportunity to share more information about the remediation, environmental testing and results, ongoing monitoring, and next steps, as well as answer questions from families. We will record the session and make it available online for those unable to attend.

We understand the continued disruption and uncertainty this creates for families. We are allowing the time necessary to complete the work thoroughly and receive the independent evaluation before reopening the campus.

We will continue to provide an update each evening and have added additional information to the FAQ page. The two new questions and answers are both copied here:

Will the district offer an information session for families before students return to campus?

Yes. We are planning to hold an in-person family information session on the evening before students return to school. The session will provide families with an update on the remediation work, environmental testing and results, ongoing monitoring, and next steps, and will provide an opportunity for families to ask questions.

We also plan to record the information session and make it available online for families who are unable to attend in person.

We will share the date, time, location, presenters, and other details as soon as the school reopening date is confirmed, and will also update this FAQ at that time.

Will the missed school days for students be made up?

The District is currently evaluating the instructional calendar and the options available for addressing the days of school missed because of the delayed opening.

We do not yet know whether the missed days will need to be made up or whether changes to the school calendar will be necessary. We will communicate with families and staff once that review is complete and we have determined how the missed instructional time will be addressed.

Evening Update - August 13, 2026

Belfor Property Restoration began work at 7:00 a.m. today with as many as 40 crew members on campus.
Crews brought additional equipment, including air scrubbers and supplemental HVAC equipment, and immediately began treating classroom spaces.

Our plan is to address all campus spaces, with crews prioritizing classrooms and offices first, followed by shared and common areas. Belfor is working double shifts (approximately 16 hours each day) to move through the campus as quickly and thoroughly as possible.

Our current goal is to complete remediation of all spaces throughout the campus by Saturday. We remain on track toward that goal. If that timeline holds, the next steps will be:

Complete remediation work by Saturday, August 15.
Conduct post-remediation environmental testing late Saturday night or early Sunday morning by an independent third-party environmental hygienist.
Receive and review those results Monday evening (August 17) and determine whether the identified issues have been appropriately resolved and confirm next steps for reopening.

One of the most common questions we have received is why the decision to delay the start of school was not made sooner.

Until the District received the independent environmental sampling results on Tuesday, August 11, teams were actively remediating affected spaces and preparing for school to open as scheduled. Based on industry-standard remediation protocols and the information available at the time, the District expected that the work underway would allow the affected classrooms to be cleared for re-occupancy.

The August 11 results showed that additional remediation was needed in more classrooms than previously understood. After reviewing the results and the additional work required, the District determined on August 12 that there was not enough time to complete the necessary remediation and follow-up evaluation responsibly before students returned.

Once that determination was made, the District notified staff and families that the start of school would be delayed.

We have heard the frustration from families about receiving this news so close to the first day of school. We understand the disruption this caused, and we are sorry. We are learning from this experience and will use those lessons to improve how we communicate when conditions are evolving and the potential impact to families is significant.

We have also added new questions to the FAQ page including:

What is the timeline of events that lead to the first day of school being postponed? When did the district first learn there was mold in these classrooms?
Why wasn't this communicated to families sooner?

Evening Update - August 12, 2026

ATI Restoration has completed its work on campus. Belfor Property Restoration will begin the next phase of remediation tomorrow morning at 7:00 a.m. This work remains on schedule as we prepare for post-remediation testing by our independent industrial hygienist on Saturday.

We have added several new questions and answers to our FAQ page to provide additional information about the remediation, testing, and process for determining when classrooms are ready to be re-occupied.

We know families are eager for information, and we are committed to keeping you updated throughout this process. We will provide another update tomorrow evening and will continue sending an update each evening until Del Sur is ready to reopen.

What remediation is being done? Will there be post-remediation testing before students enter classrooms?

Yes. Professional environmental contractors are completing remediation work in classrooms identified through the most recent evaluation. Anti-microbial cleaning will also occur in all occupied indoor spaces and HVAC closets. Ductwork will be cleaned. Air scrubbers with HEPA filtration and dehumidification are also being installed in all classrooms, along with additional dehumidification or portable cooling equipment in the open rotunda area to help reduce moisture.

Following remediation, an independent contracted industrial hygienist, will reevaluate the affected spaces. Re-testing is scheduled for Saturday, August 15, with results expected Sunday or Monday, August 16 or 17. Classrooms will not be returned to normal use until the District has received the independent hygienist’s evaluation confirming that the identified issues have been appropriately addressed.

In addition, humidity-monitoring devices will be installed in every classroom so conditions can be monitored in real time, and the District will continue evaluating the broader campus conditions to identify and address any underlying causes.

When was the last time the rooms were occupied?

What if my child has an IEP?

Why couldn’t the affected classrooms simply be relocated?

What do “acceptable,” “moderate,” and “elevated” mean?

Determination of indoor air quality condition is based on the Eurofins Mold Score ranking. The score is calculated from paired indoor and outdoor air samples collected via spore traps, and it estimates the likelihood that the spores found indoors actually originated and are growing inside the building (as opposed to just blowing in from outside).

Acceptable: Less than 150; low probability of molds spores originated from indoors Moderate: 150 to 250; moderate probability of mold spores generating from indoors Elevated: More than 250; high probability of mold spores generating from indoors

Acceptable Rooms: 204, 205, 221, 224, 135

Rooms with Moderately Elevated Levels of Penicillium/Aspergillus Mold Spores - These rooms should be recleaned and resampled: 222, 127, 137, 142, 147

Rooms with Elevated Levels of Penicillium/Aspergillus Mold Spores - These rooms should be investigated for a source of mold growth, corrected, recleaned, and resampled: 123, 124, 126, 132

When will the final results be available? (Updated 8/17/26)

Based on the latest information available, and in accordance with the evening updates above, we expect to receive the results and evaluation from the independent industrial hygienist on Tuesday, August 18.

Once we receive and review that information, we will communicate with staff and families as quickly as possible. That update will include the results, the status of classroom re-occupancy, and the latest information about the school reopening timeline.

We understand that families and staff are eager for certainty about when school will reopen. We also want to make sure that decision is based on the completed remediation work and the independent hygienist’s evaluation. Affected classrooms will not return to normal use until the independent hygienist has determined that the identified issues have been appropriately addressed and the spaces are acceptable for re-occupancy.

What is the protocol for determining that a room can be re-occupied?

A classroom will be returned to normal use only after the necessary remediation has been completed and the space has been reevaluated by the District’s independent contracted industrial hygienist.

That evaluation considers multiple factors, including whether the identified moisture or mold source has been addressed, whether the recommended cleaning and remediation have been completed, the condition of the room following that work, and the results of follow-up sampling when required.

This approach is consistent with U.S. Environmental Protection Agency guidance for mold remediation in schools and commercial buildings. EPA guidance focuses on correcting the underlying water or moisture problem, removing mold and mold-damaged materials, and confirming that visible mold and mold-related odors are no longer present. When sampling is used, those results provide additional information for evaluating whether remediation has been successful.

There is no federal numerical standard that establishes a single universally “safe” level of airborne mold spores. For that reason, the determination is not based on one test result or number alone. The independent industrial hygienist considers the testing results together with the condition of the space, the work that has been completed, and professional judgment in determining whether additional remediation is necessary.

At Del Sur Elementary, any room requiring additional work will be cleaned or remediated and reevaluated, including additional sampling when appropriate. A room will not be cleared for normal occupancy until the independent industrial hygienist determines that the identified issues have been appropriately addressed and the room is acceptable for re-occupancy.

What happens if a classroom is not cleared after the next round of testing and evaluation?

If the independent industrial hygienist determines that additional work is needed in a classroom, that room will remain out of use. The District will complete the additional recommended remediation and have the space reevaluated before it is returned to normal occupancy. We will also assess what that means for the reopening timeline and communicate any changes to staff and families as quickly as possible.

Who determines whether classrooms are ready to be occupied?

An independent industrial hygienist, will evaluate the affected classrooms following remediation and determine whether the identified issues have been appropriately addressed and the spaces are acceptable for re-occupancy.

This determination is not made by District staff alone. The industrial hygienist will consider the remediation work that has been completed, the condition of each space, whether identified moisture or mold sources have been addressed, and the results of post-remediation testing.

If the independent industrial hygienist determines that additional work is needed in a classroom, that room will remain out of use while the recommended work is completed and the space is reevaluated. Affected classrooms will not be returned to normal use until the independent industrial hygienist determines they are acceptable for re-occupancy.

What is the District doing to prevent the problem from recurring?

New thermostats will be installed that can monitor room humidity and alert the Facilities Maintenance & Operations department if high levels of moisture are detected. This will allow staff to respond and adjust the HVAC systems before a problem occurs.

Staff will also consult with its architects, mechanical engineers, and HVAC technicians to seek out the cause of the higher moisture levels in the building and determine a permanent solution to the humidity problem.

Are areas other than classrooms being evaluated?

Does every classroom have to be cleaned before the school can reopen?

Why is the entire school being cleaned if only some classrooms had elevated results?

Will families and staff be able to see the testing results?

How will conditions be monitored after students and staff return?

Humidity-monitoring thermostats will be installed in every classroom so the District can monitor conditions in real time and respond promptly if elevated moisture levels are detected. Dehumidifiers will be available to remain in place as appropriate to help manage indoor air and moisture conditions.

In addition, District staff will continue to monitor the campus for signs of excess moisture and evaluate the broader building conditions to identify and address any underlying causes. If monitoring or observation identifies a concern in a classroom or other space, the District will investigate promptly and, when appropriate, consult with environmental professionals to determine whether additional evaluation, testing, or corrective action is needed.

These measures are intended to provide ongoing monitoring after the school reopens rather than treating the completion of remediation as the end of the process.

What is the timeline of events that lead to the first day of school being postponed? When did the district first learn there was mold in these classrooms?

July 6 through 13, 2026

The campus HVAC system was shut down for a planned upgrade performed by an outside contractor.
During this period, District Facilities, Maintenance & Operations (FM&O) staff also completed preventive maintenance, including coil cleaning, of the HVAC system.

Friday, July 31, 2026

The Del Sur Elementary School principal reported concerns in Rooms 123 and 124 and submitted work orders to FM&O for follow-up.

Monday, August 3, 2026

District Facilities, Maintenance & Operations staff responded to the reported concerns and arranged for inspection of the affected areas and replacement of stained ceiling tiles.

Tuesday, August 4, 2026

An additional mold concern was identified in Room 147.
The District dispatched ATI Restoration to inspect the affected areas and begin professional antimicrobial treatment in Rooms 123, 124, and 147.

Wednesday, August 5, 2026

Moisture, humidity, odor, or visible mold concerns were reported in five additional classrooms.
ATI continued professional remediation work, including steam cleaning, antimicrobial treatment, dehumidification, and the use of negative-air equipment to help address moisture and humidity.

Thursday August 6, 2026

Four additional classrooms were identified for treatment.
The District brought additional Facilities and Risk Management personnel to the site and coordinated independent environmental testing.

Friday, August 7, 2026

ATI expanded its work across the campus, including additional inspections, antimicrobial treatment, carpet cleaning, dehumidification, and air scrubbing. Elevated humidity was observed in multiple areas.
Staff were notified of the moisture-related concerns and informed that teachers assigned to impacted classrooms would be temporarily relocated when they returned to work on Monday, August 10.

Saturday, August 8, 2026

ATI continued remediation and treatment in classrooms identified through the ongoing inspections.
Dehumidification equipment remained in use to help reduce moisture levels.

Sunday, August 9, 2026

The initial phase of remediation work was completed.
The District's independent contracted industrial hygienist conducted environmental sampling in selected classrooms.
Installation and programming began for new thermostat and humidity-monitoring equipment.

Monday, August 10, 2026

Installation and programming of the new monitoring equipment continued.
District staff and contractors continued monitoring campus conditions while awaiting the results of the August 9 independent environmental sampling.
Teachers returned from summer break, with some teachers temporarily relocated from their classrooms.

Tuesday, August 11, 2026

The District received the results of the independent environmental sampling conducted on August 9.
Of the rooms sampled, five were identified as acceptable, five had moderately elevated levels, four had elevated levels, and one required retesting.
Based on the independent testing results, the District determined that additional remediation and post-remediation testing would be necessary before affected classrooms could return to normal use.

Wednesday, August 12, 2026

ATI conducted a campus-wide visual inspection of classrooms and identified microbial growth in HVAC closets, including on pipe insulation and caulking around cold copper lines. ATI recommended replacement of affected materials and deeper cleaning of HVAC components.
Based on the environmental testing results and the additional remediation work required, the District decided to delay the start of school.
Families and staff were informed of the delay and that affected classrooms would not return to normal use until the necessary work was completed and the independent industrial hygienist determined that the identified issues had been appropriately addressed.
The District contracted with Belfor Property Restoration, which had the capacity to provide more extensive remediation services, to complete the next phase of work.

Thursday, August 13, 2026

Belfor Property Restoration began remediation work on campus.
Remediation, cleaning, moisture-control measures, and other corrective work continued throughout the campus.
The District continued preparing for post-remediation testing by the independent industrial hygienist.

Why wasn't this communicated to families sooner?

Once that determination was made, the District notified staff and families that the start of school would be delayed.

Will the district offer an information session for families before students return to campus?

We also plan to record the information session and make it available online for families who are unable to attend in person.

We will share the date, time, location, presenters, and other details as soon as the school reopening date is confirmed, and will also update this FAQ at that time.

Will the missed school days for students be made up?

The District is currently evaluating the instructional calendar and the options available for addressing the days of school missed because of the delayed opening.

Will the complete testing reports be shared, and what is included in the clearance testing?

The post-remediation clearance process is designed to evaluate both the air and surfaces in the areas that were treated. Testing may include:

Air sampling: Indoor air is collected and analyzed for airborne mold spores and compared with outdoor control samples.
Surface sampling: Tape-lift samples are collected from selected surfaces, such as carpet, walls, windowsills, or other areas of concern, to determine whether active mold growth remains.
Additional material sampling, when appropriate: In some areas, wall-core or other targeted sampling may be used to evaluate conditions that cannot be assessed through air or surface testing alone.
Visual and environmental evaluation: The industrial hygienist reviews the condition of the space, including moisture and humidity conditions, alongside the laboratory results.

What were the ESS room assignments during the summer of 2026?

Families whose child participated in the summer ESS program will be notified directly by email with their child’s room number. To protect student privacy, the District will not publish the names of individual students.

As shared in a previous section of the FAQ, at the time of the summer ESS program, there were no concerns reported in ESS classrooms, and the moisture related concerns developed well after the program had concluded.

Why haven’t we seen the final reports from the most recent round of independent testing?

There are several steps between environmental sampling and the completion of the industrial hygienist’s final written report.

The general process is:

Approximately 12–36 hours after testing: Once laboratory results have been processed, the industrial hygienist typically provides the District with a verbal overview of the findings.
Generally within a day of the verbal update: The District receives a spreadsheet containing preliminary testing results.
Generally 7–10 days after testing: The industrial hygienist provides the final written report, which includes the complete findings and additional details.

This means the District may receive and communicate preliminary results before the final written report is available.

As soon as we receive the final report, we will post it online and notify families that it is available for review.

Will the district host another Family Information Night before reopening Del Sur?