Evaluating Water Systems & Equipment Before Re-Opening After Shutdown

COVID-19, Property & Casualty, Risk

Water systems and equipment are an integral part of your building, and it’s important to evaluate their condition before reopening your facility when stay-at-home orders are lifted. Stagnant or standing water can cause conditions that increase the risk for growth and spread of Legionella and other biofilm-associated bacteria, such as when hot water temperatures decrease to a range that makes it possible for Legionella to grow. Stagnant water can also lead to low or undetectable levels of disinfectants.

Use the guidance below to inform your evaluation before reopening your building.

 Assess Equipment Needs and Safety Training Requirements

Initially assess personal protective equipment (PPE) needs and appropriate safety training requirements for water system maintenance & surface decontamination (e.g., respirator, gloves, safety glasses/ goggles, proper disinfectant use, etc.)

Ensure employees or contractors performing the building restart utilize appropriate PPE, including filtering face piece respirators such as N95s or greater protection factor options.

NOTE: Respiratory protection (voluntary or mandatory) triggers specific requirements of the OSHA Respiratory Protection Standard (29CFR1910.134), including proper training as well as understanding limitations of various types of respiratory protection.

Follow strict administrative controls and personal hygiene including hand washing following all cleaning tasks along with appropriate use of hand sanitizers to limit spread of bacteria and virus.

Flush, Clean or Change All Water Systems, Fixtures, and Filters

Flush hot and cold water through all points of use (e.g., showers, sink faucets). Flush until the hot water reaches its maximum temperature.

NOTE: Flushing may need to occur in segments with the purpose of replacing all water inside building piping with fresh water and can be best accomplished with the assistance of a qualified building maintenance/engineer or by contacting your property owner.

The systems, fixtures, and filters you should flush, clean, or change can include but are not limited to:

  • Sinks, shower heads, tubs, spas, drinking fountains
  • Ice maker filters, water in-line filters, system filters
  • Water heaters
  • Centrally installed humidifiers/misters
  • Cooling towers
  • Decorative water features/fountains
  • Water softeners
  • Coffee makers
  • Dishwashers

Water Heaters

Ensure water heaters are properly maintained and that the temperature is correctly set to at least 120°F. Determine if manufacturer recommends draining the water heater after a prolonged period of disuse.

Safety Equipment

Ensure safety equipment including fire sprinkler systems, processing lines, eye wash stations, safety showers (janitorial closets) are clean, well-maintained, and flushed.

Disruptions in Water Supply

Contact your local water utility or municipality to determine if there have been any recent disruptions in the water supply.

Standard checkpoints near the building or at the meter have recently been checked or request that disinfectant residual entering building meets expected standards

Regularly check water quality parameters such as temperature, pH, and disinfectant levels after water system has returned to normal

HVAC Systems

    Perform HVAC review/inspection/preventative maintenance

Replace all air handling unit (AHU) filters with high-efficiency filters (MERV 13 or greater if system supports)

Ensure condensate drains are flushed/cleaned and consider use of biocide packs to minimize bioaccumulation

Ensure fresh outdoor air-infusion is considered and adjusted appropriately based on occupant load following ASHRAE guidelines


Source: The Hartford Steam and Boiler

Bring in a qualified Boiler Inspection contractor to evaluate all mechanical equipment for proper operation

    Perform inspection to low water cutoff and make-up water feeding devices

    Burner equipment should be cleaned, inspected and adjusted to give maximum efficiency

    Safety and safety relief valve should be tested for freedom of operation

    If boiler is of a type designed to permit cleaning of water spaces, this should be performed

    All pressure and temperature controls and gauge should be inspected

    Repair any leaking pipes or fittings on entire system

Consider High-Touch Surface Disinfecting

Perform cleaning/disinfection on all high touch surfaces prior to re-open including but not limited to:

  • Door handles
  • Table top surfaces
  • Microwave handles
  • Refrigerator/freezer handles
  • Vending machines
  • Locker-room door handles and lockers

Increase cleaning schedule and frequency based on your specific site business continuity pandemic response plan expectations.


Thoughtful consideration in determining your specific facility water management strategy is a key factor for preparing your building(s) for opening or restart as a part of your broad COVID-19 pandemic response.

For a comprehensive approach, check out the CDC 8 Steps to take before your business or building reopens, as well as ASHRAE Guideline 12-2000 & 188-2018, to ensure that your water system is at minimal risk of bacterial growth associated with Legionnaires’ disease and other bacteria after a prolonged shutdown.

There are actionable toolkits established by the CDC for developing a Water Management Program targeting reduced bacterial growth and limiting spread within building water systems. Contact your M3 Account Executive or our in house risk managers for additional consultation.

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