Icon for Cleaning

Site Safety

How do we use and clean space to make it safer?



LEAs will have to rethink the day-to-day use of facilities and school operations to limit staff and student exposure to the novel coronavirus in accordance with the latest public health information and best practices. This will necessitate new thinking around the use of space, nutrition and meal services, cleaning and disinfecting, ventilation, and other things. 




Because the virus that causes COVID-19 is transmitted when an infected person is in close proximity to others, increasing distance and reducing contact between people will help prevent the spread of the disease. As our learning spaces were designed with spacing considerations that do not always match these enhanced requirements, rethinking how to best use and clean physical space will help keep students and staff safe. 

Cleaning with products containing soap or detergent reduces germs on surfaces by removing contaminants and decreases risk of infection from surfaces.


Disinfecting (using U.S. Environmental Protection Agency (EPA)’s List N disinfectants) kills any remaining germs on surfaces, which further reduces any risk of spreading infection.


When to Clean and When to Disinfect

Clean daily when there are no confirmed or suspected cases. Cleaning once a day is usually enough to sufficiently remove viruses that may be on surfaces and help maintain a healthy facility.


Disinfect when there is a confirmed case. If there has been a sick person or someone who tested positive for COVID-19 in your facility within the last 24 hours, you should clean AND disinfect the space occupied by that person during that time. 


Increasing the cleaning frequency. You may want to either clean more frequently or choose to disinfect (in addition to cleaning) in shared spaces if the space is a high traffic area or if certain conditions apply that can increase the risk of infection from touching surfaces, such as:

For more information on cleaning a facility regularly, when to clean more frequently or disinfect, cleaning a facility when someone is sick, safe storage of cleaning and disinfecting products, and considerations for protecting workers who clean facilities, see the CDC’s Cleaning and Disinfecting Your Facility.



Recent evidence indicates that in-person instruction can occur safely without minimum physical distancing requirements when other mitigation strategies (e.g., masking) are implemented. This is consistent with CDC K-12 School Guidance.


Other Space Considerations

  • Reopening Buildings After Prolonged Shutdown: After a long time of inactivity, buildings may require additional attention. Take steps to ensure that all water systems and features (for example, drinking fountains and decorative fountains) are safe to use after a prolonged facility shutdown to minimize the risk of Legionnaires’ disease and other diseases associated with water. The CDC offers guidance for reopening buildings after prolonged shutdown
  • Identify and Set Up an Isolation Area: Work with school administrators, nurses, and other healthcare providers to identify an isolation room or area to separate anyone who exhibits symptoms of COVID-19. 
  • Limiting Access to Schools: Schools should limit nonessential visitors, volunteers, and activities involving external groups or organizations with people who are not fully vaccinated, particularly in areas where there is moderate-to-high COVID-19 community transmission.
  • Ensure Access for Service Providers: Schools should not limit access for direct service providers, but can ensure compliance with school visitor policies.
  • Post Helpful Signage: Consider posting signage at each public entrance of each site to inform all students, staff and visitors that they should: 
    • Avoid entering or using the facility if they have COVID-19 symptoms; and
    • Wear face coverings, as appropriate.


The virus that causes COVID-19 spreads in droplets that are exhaled by someone who has the virus. Ventilation can reduce the amount of viral particles in a specific area by diluting them, and thus help decrease the risk of exposure. 

For indoor spaces, ventilation should be optimized, which can be done by following CDPH Guidance on Ventilation of Indoor Environments and Ventilation and Filtration to Reduce Long-Range Airborne Transmission of COVID-19 and Other Respiratory Infections: Considerations for Reopened Schools.


Practical Implications 

Multiple protective strategies can help to substantially reduce the risk of long-range airborne transmission of SARS-CoV-2 in classrooms. These include:


  • Mask wearing: All individuals (teachers, students, staff, etc.) should wear masks under all ventilation rates or air filtration conditions in the classroom. This practice reduces both short-range and long-range airborne transmission risk comparing to not wearing a mask.
  • Outdoor air ventilation: The system should provide at least the code-required minimum ventilation rate (per California Title 24). In classrooms with no ventilation and no filtration, the risk of long-range airborne infection would be over six times as high as that for classrooms with code-required ventilation and a MERV 8 filter.
  • Filtration: Ventilation system filters should be MERV-rated at MERV 13 or better. They should also be properly installed (i.e., no gaps that would allow air to bypass the filter) and properly maintained (i.e., replaced as often as recommended). MERV-rated filters can provide substantial protection from long-range airborne infection, especially if ventilation is poor.
  • In-room (portable) air cleaners: Air cleaners used to reduce the risk of long-range airborne transmission should provide high-efficiency filtration and a sufficient “clean air delivery rate” (CADR) (i.e., at least 2/3 of the floor area). Such air cleaners can provide substantial additional protection, especially in naturally ventilated classrooms (in which air is supplied only through open windows or doors) or in classrooms with non-functioning or poorly functioning ventilation systems. Multiple devices per classroom may be necessary for sufficient total air cleaning.
  • Avoid: Classrooms and buses without ventilation and classrooms/buses with increased airflow across occupants (e.g., air conditioners or fans blowing into classrooms or overhead fans blowing down onto occupants)


Meal time is traditionally one of the periods during a school day in which students and staff are in the greatest proximity to each other and, thus, at greatest risk of exposure to COVID-19. LEAs will want to plan on finding ways to maximize physical distance as much as possible while eating (especially indoors).


  • Outdoors and Classrooms: Using additional spaces outside of the cafeteria for mealtime seating such as classrooms or the gymnasium can help facilitate distancing. Arrange for eating outdoors as much as feasible. 
  • Clean frequently touched surfaces. Surfaces that come in contact with food should be washed, rinsed, and sanitized before and after meals.
  • No Need to Limit Services to Individually Plated or Bagged Meals: Given very low risk of transmission from surfaces and shared objects, there is no need to limit food service approaches to single use items and packaged meals.
  • Contactless Systems: Consider using contactless systems, such as touchless point-of-sale systems and e-payments, to reduce direct contact with common surfaces and currency.
  • Limit Sharing: Limit use and sharing of objects and equipment, items such as trays, condiments, or tables to one group of children at a time and clean between uses.


For more information about how this tool was created and answers to other questions, see the FAQ section.  

Last updated on October 8, 2021. 

The Health & Safety Guidebook for California LEAs
The Health & Safety Guidebook for California LEAs was developed in collaboration with the
California State Board of Education, the California Department of Public Health, and other technical assistance partners.