Stagnant water is a breeding ground for bacteria. Before reopening shuttered buildings, the internal water systems need to be investigated, plumbing experts say.

Hotels and office buildings line the Riverwalk in downtown Chicago. Photo © J. Carl Ganter/Circle of Blue

By Brett Walton, Circle of Blue

The last event held at Angel of the Winds Arena, an entertainment and conference center in Everett, Washington, before it closed because of the coronavirus pandemic was a junior hockey league game. The game ended in a blowout, with the Seattle Thunderbirds crushing the hometown Silvertips by a score of 5 goals to 2.

That game was on March 7. Nearly a month later, on April 1, the facility 25 miles north of Seattle reopened to the public — as a quarantine site.

Countless buildings across the country have experienced extended idle periods and unexpected transformations during the global health crisis. Hotels, offices, restaurants, churches, and college campuses are vacant or operating at drastically reduced capacity. Like Angel of the Winds, some buildings have been repurposed as field hospitals, emergency medical wards, or sites for self-isolation. Retired buildings, meanwhile, are being pressed into service. Hospitals in Chicago, Los Angeles, and Phoenix that closed months or years ago have been rebooted to serve the swelling ranks of individuals stricken with Covid-19, the disease caused by the new coronavirus.

Building closures have obvious repercussions for local economies and social connections. Politicians want to lift stay-home orders and reopen public and private spaces as soon as the health risks from Covid-19 are manageable.

But before the all-clear signal is flashed, one hidden risk should not be overlooked, plumbing experts say. Prolonged closures can degrade water quality within buildings and introduce into the water harmful pathogens like Legionella bacteria and chemical contaminants such as lead. Certifying a building as fit for reopening means clearing the plumbing system, they say.

“There can be unintended consequences,” Christoph Lohr, a director and plumbing engineering specialist at LiquiTech, a water management firm, told Circle of Blue about building closures. “We don’t want to see a second crisis of waterborne disease.”

An Unprecedented Event

To have entire city districts filled with buildings that are largely empty for weeks and months is an unprecedented event for plumbing systems, says Andrew Whelton, a Purdue University environmental engineer.

To inform the safe reopening of buildings, outline the challenges and information gaps, and serve as a foundation for individual building plans, Whelton and eight plumbing experts from across North America published a rapid-response review of existing literature on water stagnation in plumbing.

There is established guidance for reopening after seasonal closures that hotels in resort towns would experience, and for inaugurating a new building. But for widespread shutdowns of this magnitude and extent, building owners, regulators, and utilities, are essentially flying blind, Whelton said.

“Ultimately you want to know if the plumbing is safe,” Whelton said. “And the only way to know is to test.”

But test for what? And where? And in what parts of the plumbing system? There is still much to learn about the extent to which old water will pose a health risk and what needs to be done to address it, the review concluded.

“This is a big issue,” Pete DeMarco, executive vice president of advocacy and research at IAPMO, a plumbing trade group, told Circle of Blue. “There are a lot of building types and systems to be taken into account.”

One obvious indicator is chlorine or other chemicals that are employed as drinking water disinfectants. Chlorine, which kills most but not all bacteria, degrades in a matter of days in some cases. Any bacteria that were not initially disarmed could recolonize the inside of pipes, nozzles, joints, and other elements of plumbing and faucet fixtures.

Another task is purging the system of old water. Plumbing design will dictate flushing times, with pipes that are farther away from the city distribution main needing more time, potentially an hour in some buildings, Whelton said. Pipe material, the chemical composition of the water, and the current condition of the pipes are also factors.

For buildings that are being repurposed as medical facilities or quarantine sites, other questions should be asked, said Caitlin Proctor, a postdoctoral fellow at Purdue and a contributor on the study.

“What are patients using water for?” Proctor said. If it is only for washing floors, then less caution is needed. “If the water is used for showering, the quality needs to be high because of the risk of Legionella.”

Legionella bacteria like to grow in warm, stagnant water. The bacteria cause Legionnaires’ disease, an illness that spreads through contaminated droplets and resembles pneumonia. It kills more U.S. residents than any other waterborne pathogen.

Case by Case

Responses in buildings so far are ad hoc, largely taken by facility managers. Whelton said the circumstances reminded him of previous water contamination crises that he has responded to: a coal-industry chemical spill in the Elk River that temporarily halted water service in Charleston, West Virginia, in 2014, and the corruption of the plumbing system in Paradise, California, following the Camp Fire, in 2018. In those cases, patchwork guidance produced a confused response.

For the Covid-19 crisis, industry and governmental agencies — American Industrial Hygiene Association, IAPMO, and the Centers for Disease Control and Prevention — have published barebones guidance documents that acknowledge water in buildings is at risk of bacterial and chemical contamination.

Lohr said that his firm’s clients generally are not yet thinking about the plumbing logistics of reopening their building.

“It’s in the early part of the conversation,” Lohr said. “Everyone has been in panic mode, and still grappling with what is going on.”

Lohr added: “No one two to three months ago had any idea this was coming.”

The fact that building owners are still determining what to do is why Whelton and his colleagues published their review so quickly. The work was funded by the National Science Foundation’s rapid grant program, which supports urgent science in the face of natural or man-made disasters.

At Angel of the Winds Arena, staff made sure that the building was never completely shuttered. Mark Clark, director of engineering, said that the hot water system was kept continuously circulating, and the staff still used water to clean the rink and arena floors. As a quarantine site, the facility has cots for 150 people, who will be able to use the showers in the locker rooms during their stays, according to Kent Patton, a Snohomish County spokesperson.

Lohr and others said that the next few months are a crucial window for calibrating a response plan, especially against pathogens, for recommissioning the water system in buildings. That is because of heightened disease risk.

Legionnaires’ disease cases display seasonal shifts and geographic patterns: they spike in the late summer and early fall, and are most prevalent in the Great Lakes states and the mid-Atlantic region. Those are two areas that have been hit hard by Covid-19.

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