Building Shutdown and Re-opening during the COVID-19 Pandemic

Printer Friendly, PDF & Email

Temporarily closed due to COVID-19[Last Updated: Feb 11, 2021]

During the ongoing COVID-19 pandemic, it may be necessary to periodically close public buildings and facilities, followed by re-opening when safe again. Periods of low or no occupancy can be challenging for building systems as deviation from standard operations may increase the risk of water system failures, fires, mould growth, pest infestation, and other complications. Reduced consumption of water can cause stagnant water to accumulate in building water systems where taps, showers, ice machines, fountains, or other water features are not in use. This can lead to reduced water quality and other hazards such as Legionella exposure once buildings are reoccupied. The risks can vary depending on the length of shutdown, building features (e.g., lead piping, presence of cooling towers, decorative water features, etc.) and whether there is routine maintenance of systems during the shutdown.

The resources provided on this topic page are intended to inform EH professionals and assist property managers with enacting a temporary closure, as well as cleaning, re-initializing, and safely operating public or commercial facilities under pandemic conditions. The resources are examples only and additional considerations may be required for specific facility types and site conditions. This information is current to the date at the bottom of the page.

NCCEH Resources

External Resources

Shifting to low- or no-occupancy operations

Re-opening and operating under pandemic conditions

General Resources


Restoring and Maintaining Water Quality

  • Safely re-opening buildings: A fact sheet for building owners/operators (Canadian Water and Wastewater Association, May 2020)
    This factsheet explains the risks of stagnant water in buildings operating at low or no occupancy, including the risks of microbial growth, heavy metal leaching, and disinfection by-product formation, and provides detailed guidance on developing a risk mitigation and reopening strategy.
  • Guidance for managing Legionella in building water systems during the COVID-19 pandemic (European Society for Clinical Microbiology and Infectious Diseases (ESGLI), 2020)
    ESGLI has produced guidance documents for various types of buildings. The link above provides guidance applicable to hotels, campsites, cruise ships, residential and office buildings with similar water systems. Guidance is also available specific to
    dental practices, with dental unit water lines, nursing & care homes and hospitals.
  • Making a splash with safe water (CDC, Feb 2020)
    This fact sheet provides a reminder for hotels and resorts of where Legionella can grow and spread in buildings including cooling towers, unoccupied floors, hot tubs, decorative fountains, or during events that can interrupt normal water supply.
  • Considerations for large building water quality after extended stagnation (Proctor et al. Jun 2020)
    This literature review by researchers at Purdue University, Centre for Plumbing Safety, summarizes challenges, current practices and knowledge gaps for recommissioning water systems following extended periods of reduced use. The document refers to existing guidance on building commissioning, and start-up following seasonal shutdowns as examples of current practice to reduce health risks.


Restoring and Maintaining Air Quality

  • Preparing HVAC systems before reoccupying a building (McCarthy and Coghlan, ASHRAE, Jan 2021)
    This technical brief outlines the key steps for moving HVAC systems from no to low use to full occupancy following a prolonged shutdown. Measures include inspection, maintenance and testing, and assessing the implications of new operational settings, such as increasing outdoor air intake, for reducing COVID-19 transmission risks.
  • Ventilation in buildings (US Centres for Disease Control and Prevention, Dec 2020)
    This webpage lists ventilation related mitigation measures for reducing transmission risks of COVID-19 indoors and FAQs on ventilation and COVID-19.
  • Transmission from HVAC systems (Alberta Health Services, Jun 2020)
    This expert panel reviewed the available literature on SARS-CoV-2 transmission in hospital and non-hospital settings. 


This list is not intended to be exhaustive. Omission of a resource does not preclude it from having value.

Last updated Feb 11, 2021