Reposted from The Conversation and its series of articles.
The coronavirus pandemic might make buildings sick, too
While millions of people are under orders to stay home amid the coronavirus pandemic, water is
sitting in the pipes of empty office buildings and gyms, getting old and potentially dangerous.
When water isn’t flowing, organisms and chemicals can build up in the plumbing. It can happen
in underused gyms, office buildings, schools, shopping malls and other facilities. These organisms
and chemicals can reach unsafe levels when water sits in water pipes for just a few days. But, what
happens when water sits for weeks or months?
There are no long-term studies of the risks and only minimal guidance to help building owners
prepare their water for use again after a long shutdown.
As researchers involved in building water safety, we study these risks and advise building owners
and public officials on actions they can take to reduce the potential for widespread waterborne
disease. A new paper highlights these issues and our concerns that the COVID-19 stay-at-home
orders may increase the chance of harmful water exposure when people return.
What happens when water gets old?
Just like food that sits in a refrigerator for too long, water that sits in a building’s pipes for too long can make people sick.
Discolored water can be caused by heavy metals, such as iron or copper. Iron can also act as a nutrient for organisms to grow in the pipes.
Harmful organisms, like the bacteria that cause Legionnaire’s disease, can grow. If not maintained,
devices like filters, water tanks, heaters and softeners can become organism incubators.
With certain pipe materials, water can accumulate unsafe levels of lead and copper, which can cause
learning disabilities, cardiovascular effects, nausea and diarrhea.
Drinking this water is a problem, but infections can also result from inhaling harmful organisms. This
occurs when water splashes and becomes an aerosol, as can happen in showers, hot tubs and pools
and when flushing toilets or washing hands. Some of these organisms can cause pneumonia-like
diseases, especially in people who have weakened immune systems.
Water inside a building does not have an expiration date: Problems can develop within days at
individual faucets, and all buildings with low water use are at risk.
Keep the water flowing
To avoid water issues, “fresh” water must regularly flow to a building’s faucets. Most U.S. water
providers add a chemical disinfectant to the water they deliver to kill organisms, but this chemical
disappears over time.
Medical facilities, with their vulnerable populations, are required to have a building water safety plan
to keep water fresh and prevent growth. Schools, which have long periods of low use during the
summer, are advised to keep water fresh to reduce water’s lead levels.
Health agencies in the U.S., Canada, England, Europe and some states have released
recommendations in recent weeks, advising that building water be kept fresh during COVID-19 stay-at-home orders. There’s some debate over the best way to do that, but the core message is the same:
Do not let water sit in buildings.
If water isn’t being used in a building, intentionally flushing the building to replace all the old water
with new water can be done at least weekly. It also helps remove sediments that accumulate along
Faucets, water heaters and softeners, appliances such as refrigerators, toilets and other water systems,
including cooling towers, all need to have water turnover. Some of these can require specialized
attention. Faucet aerators should be removed because they accumulate materials and slow down the
How long flushing takes depends on the building’s piping design, devices and the speed of water
exiting the faucets. All buildings are different.
It took more than 80 minutes of flushing to draw fresh water to the farthest faucet of one 10,000-
square-foot building. In another building, it took 60 minutes just to get fresh water from the water
meter to the basement of a building 30 feet from the street. A single large building may take hours or
days to clear.
Easier to avoid contamination than clean it up
For building managers who haven’t been running the water during the pandemic, the water sitting in
pipes may already have significant problems. To perform flushing, safety equipment, including masks,
currently in short supply, might be needed to protect workers.
A slow “ramp-up” of the economy means buildings will not reach normal water use for some time.
These buildings may need flushing again and again.
Shock disinfection, adding a high level of disinfectant chemical to the plumbing to kill organisms
living in it, may also be necessary. This is required for new buildings and is sometimes done when water in new buildings sits still for too long.
Inexpensive chemical disinfectant tests can help determine if the water is “fresh.” Testing for harmful
organisms is recommended by some organizations. It can take several days and requires expertise to
interpret results. Metals testing might be needed, too. Public health departments can provide specific
recommendations for all of these actions and communication of risks.
The need for standards and water safety
Water left sitting in the pipes of buildings can present serious health risks.
Standards are lacking and very much needed for restarting plumbing and ensuring continued water
safety after the pandemic passes.
Right now, building managers can take immediate action to prevent people from becoming sick when
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