The novel coronavirus is leaving few stones unturned as it wreaks havoc on worldwide populations and economies. One of those stones may be our drinking water. When buildings have low water use, safety additives like corrosion inhibitors and disinfectants may no longer work and uncontrolled chemical and microbiological reactions can occur. As we began to shut down our own research labs, we applied for a National Science Foundation Rapid Response Research (RAPID) grant to capture data in underused buildings that could help us paint a picture of what may be happening in millions of buildings globally.
When populations chose to distance themselves from recreation, workplace and education buildings to avoid catching the virus, the water in those buildings’ pipes and tanks stayed behind. This profound stillness, or stagnation, has prompted safety concerns. Further, when buildings reopen, they’re using less water, and this allows more potential for water to expire.
Heavy metals such as copper and lead can leach from plumbing under normal circumstances. Before the pandemic, we sometimes saw copper drinking water levels exceed safe limits in just a few hours. Heavy metals can cause acute effects ranging from nausea to vomiting, diarrhea, and — for some metals — developmental issues in children.
Legionella pneumophila, which can cause Legionnaire’s disease, and other disease-causing organisms also grow in building pipes and tanks under normal circumstances. When water stagnates and becomes warm (like room temperature), and no chemical disinfectant is left in the water to protect it, these organisms can flourish.
It’s unknown what happens after months of no water use. It’s also unclear what happens when water is consistently older before it reaches the faucet.
We do know that as the water sits, the residual disinfectant that controls microbiological growth slowly disappears, and when it’s gone, the biofilm present on most pipe walls can grow more freely. Much of this organism growth has no health consequences, but several pathogens are well-suited to propagate in building pipes. A number of these pathogens are opportunistic, meaning they particularly affect people with weakened immune systems, including older people, and those with preexisting lung conditions). Many of the organisms cause pulmonary (lung) infections after they are inhaled.
Aerosols from showers, sprayers, misters, hot tubs and other devices are especially risky. We’re specifically worried about Legionella pneumophila, non-tuberculous mycobacteria, and other amoeba and bacteria; co-infections between L. pneumophila and COVID-19 have also been documented. No one wants an increase in bacterial pneumonia during a global pandemic.
This is all happening to an already-strained drinking water infrastructure. Most of our pipes are old; thanks to the surge in lead levels during the Flint, Michigan, water crisis, we are painfully aware of the issues these pipes cause. Our infrastructure also does not match current use patterns. In the past 20 to 30 years, the U.S. has embraced water-efficient designs, but the pipes in buildings and distribution networks are designed for larger flows. Pipes that are too large can increase stagnation times unnecessarily.
Drinking water is a human right, and in the U.S., we expect it is safe when it comes out of our taps. The stay-at-home orders have created a long-term stagnation event in many buildings across the country. Even as people begin to return to work, schools, gyms and other buildings, they will find water use changed in a way that may affect water quality for months to come. For example, when some sinks are closed to enforce distance, those individual taps will have long-term stagnation. Growth that occurs in these fixtures could affect the entire building.
The good news is that proper maintenance might be able to prevent water issues. If building water use can be simulated at the same level as during full building occupancy, or even increased with targeted flushing, extended stagnation won’t take place. Automatic flushers can be installed on faucets to keep water moving. Building staff can manually operate the fixtures. When maintenance during building shutdown is untenable more extreme flushing or disinfection might be needed prior to reopening. During this initial flush, personal protective equipment is necessary to prevent worker exposure to harmful water or aerosols.
The water safety issues occurred as water safety issues were already pervasive, and designed into the system. The lack of testing data for new and in-service buildings is another problem. Adherence to plumbing codes, guidelines, and standards does not mean the water won’t harm someone — some of the information in these standards has no evidentiary basis! And general bacteria testing, if anything, is typically the only test required (no specific pathogens are tested).
The safety of water should be regulated all the way to the tap — not just to the exit of the treatment plant or the meter, as it is now. With the lack of prior focus, we are where we are today. It is incumbent upon all building owners to make certain their water does not harm people.
Caitlin Proctor, PhD, Lillian Gilbreth Postdoctoral Fellow, Schools of Civil, Environmental and Ecological, Materials, and Biomedical Engineering, College of Engineering, Purdue University
Andrew Whelton, PhD, Associate Professor of Civil Engineering and Environmental and Ecological Engineering, College of Engineering, Purdue University