Water; Go With the Flow… And Manage It Well

While no strategy can eliminate all risk, it is imperative that Water Management actions are rooted in good science to protect the value of investments in buildings and people.

A basic premise of building water systems is that water should flow as much as possible, avoiding water stagnation. Water left to age inside pipes and fixtures loses its disinfectant abilities, allowing microbes to flourish, and reacts with pipe walls to leach compounds. 

So what happens after the unexpected building shutdowns due to COVID-19? As these pandemic times stretch on, we are beginning to better understand the answers.

Along with industry experts working in the building water sector and public health authorities around the world, I pointed out a few months ago the risks that building water systems may face as they reopen due to water sitting idle in pipes, fixtures and other devices. One of the main concerns is the colonization of water systems such as hot water pipes, spa pools and cooling towers by Legionella bacteria, which causes Legionnaires’ disease, a type of pneumonia that can kill up to 10 percent of those who contract it and is triggered by the inhalation of contaminated water aerosols.

One of the main concerns is the colonization of water systems by Legionella bacteria…

Rodolfo Perez, Ph.D.

Amidst the pandemic, reports of building closures due to Legionella have become more common: schools across many U.S. states were forced to shut down, and even the U.S. Centers for Disease Control and Prevention (CDC) was forced to close many of its buildings. As a result of loss of water quality due to stagnation during lockdowns, Legionella is more likely to grow in building plumbing systems which may result in increased cases of Legionnaires’ disease. There have been some instances where cases of co-infection of Legionnaires’ disease and COVID-19 have been reported.

The Benefits of Proactive Water Management

During the lockdown, buildings may have implemented good practices to reduce the risk of widespread Legionella contamination, such as periodic flushing. However, the sudden building closures required to respond to the pandemic may have left many buildings ill-prepared. If anything, this crisis has been a wakeup call to remind us to work to protect the health of the building to benefit the people inside, and a sobering reminder of the value of good building management practices, which include implementing plans to maintain water qualit.

Beyond the clear benefits to promoting the human health of the building occupants and maintenance workers, proactively managing water is beneficial for many other reasons. In general, addressing mold, Legionella and other water pathogens such as Pseudomonas aeruginosa is easier and cheaper to handle during earlier stages of colonization. In many cases, finding some non-zero levels of Legionella does not require a full-scale remediation, as these organisms are naturally present. Good management plans include protocols to periodically monitor water quality and establish regular inspections and a set of actions to reduce risks of system contamination. These risk reduction activities may include targeted flushing of certain water assets, checking disinfectant levels in drinking water and cooling towers, inspecting for pipe leaks or maintaining HVAC equipment.

The current COVID-19 pandemic has been a wakeup call to protect the health of the people inside our buidings, and a reminder of the value of good building management practices – including plans to maintain water quality. 

The Costs of Failing at Proactive Water Management

The downsides of not proactively managing water systems can be high, as remediating buildings after discovery of later stages of colonization can be costly. For instance, high levels of Legionella in cooling towers may require temporarily decommissioning these devices, which may result in shutting down building cooling systems that make buildings hospitable during summer months. Similarly, multifamily residential buildings or hotels where Legionella is found may need to turn off hot water loops, effectively stopping people from taking warm showers. 

Things can get even more complicated if cases of Legionnaires’ disease are suspected to be associated with a building. In many jurisdictions, epidemiological surveillance offices pursue environmental building investigations for Legionella reservoirs. Authorities may enforce building remediation if Legionella is detected in these situations. Insurance companies are taking note and starting to evaluate the risk associated with building water practices upon reopening. In a recent report, Allianz Global Corporate & Specialty (AGCS) highlighted Legionella and/or mold claims as one of the trending sources of risks faced by companies.

Finding the Right Flow

While no strategy can eliminate all risk, it is imperative that actions are rooted in good science to protect the value of investments in buildings and people. In response to these issues, newly released WELL v2 – the latest version of the WELL Building Standard – and WELL Health-Safety Rating for Facility Operations and Management, focus on strategies such as developing and implementing Legionella management plans, periodic water quality testing and mold inspections. The recommendations embedded in these systems can go a long way toward helping owners and facilities managers to review and revise their building management policies, and to accept the challenge of providing healthier environments for people. The time is now.


  1. Sleeping giants: Awakening building water systems; Rodolfo Perez, IWBI, June 3, 2020
  2. Legionella (Legionnaires’ Disease and Pontiac Fever) Fast Facts, U.S. Centers for Disease Control and Prevention
  3. Reopened schools find health risks in water after Covid-19 lockdowns, New York Times, August 27, 2020
  4. Coronavirus shutdown causes new risk at CDC: Legionnaire’s disease, CNN Health, August 7, 2020
  5. Wandering a grand hotel emptied by Coronavirus, and checking 1,400 taps, New York Times, May 17, 2020
  6. US Insurers eye Legionnaires’ Disease safeguards as buildings open from lockdowns, Voice of America, June 19, 2020
  7. Allianz: Companies face five liability risk trends amid the coronavirus pandemic, Allianz, September 9, 2020
  8. WELL v2 Water concept overview, IWBI, 2020
  9. WELL Health-Safety Rating for Facility Operations and Management, IWBI, 2020

This article was written by Rodolfo Perez, Director, Standard Development, International WELL Building Institute (IWBI)

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