By: Christopher Sirota, CPCU
What happens when you don't use your water pipes?
In 2019, Citylab explained that cities in the U.S. with shrinking populations have experienced poor water quality because of underutilization and underfunding of the drinking water infrastructure. The article noted that with smaller populations naturally comes lower water demand. When this is the case, water reportedly can remain in pipes for longer times—known by researchers as "water age"—increasing the risk of both lower levels of disinfecting chemicals, such as chlorine, and higher levels of microbes that can cause waterborne diseases.
Now, during the COVID-19 crisis, some experts have expressed concern that something similar may be happen in buildings after having been closed or subject to low usage because of the various lock down rules in place around the world.
The American Industrial Hygiene Association (AIHA) notes in its guidance that there is a risk of getting the water-borne Legionnaires’ disease after re-opening a building even after just one week of closure.
Some examples of current closures in the U.S. include the following:
- Per Education Week, crisis-related school closures have affected "at least 124,000 public and private schools."
- Over "400 [U.S. General Services Administration (GSA)] owned and/or managed federal buildings," have been closed, according to their emergency response website.
- CNBC reports that over 15,000 retail stores may close permanently because of the crisis, so most likely a large percentage of these are currently closed.
- Per Curbed NY, 32 of Broadway's theaters are closed as well.
A New Study Released
According to an article by the environmental advocacy group Circle of Blue, engineers at Purdue University published a pre-print study (full report here) entitled "Water Quality in Low Occupancy and Shutdown Buildings", which examined various concerns related to building closures and reopenings related to the crisis.
Per the article, "[h]otels, offices, restaurants, churches, and college campuses are vacant or operating at drastically reduced capacity" because of the crisis, and "[p]rolonged closures can degrade water quality within buildings and introduce into the water harmful pathogens like Legionella bacteria and chemical contaminants such as lead."
Much like the concerns with water systems in the shrinking cities mentioned above, since the common disinfecting chemical chlorine reportedly can degrade over a few days after low or zero usage, "[a]ny bacteria that were not initially disarmed [by the chlorine] could recolonize the inside of pipes, nozzles, joints, and other elements of plumbing and faucet fixtures."
The article also notes that upon re-opening, a plumbing system may need flushing out, and "pipes that are farther away from the city distribution main [may need] more time, potentially an hour in some buildings." Furthermore, per the report:
[a]s plumbing is designed to maintain pressure, drainage may introduce backflows and contamination from other water systems such as cooling towers and fire protection systems if efficient backflow prevention is not in place. Challenges associated with draining water from plumbing include the destabilization of sediments and biofilms when refilled and introduction of external contaminants to the pipes.
The report also mentions that the safety of the workers that are enlisted to flush a building's system needs to be considered. Such risks reportedly include exposure to contaminants, for example, since:
[i]nitial flushes of stagnant water and associated transient pressure events can release high concentrations of chemical and microbiological contaminants due to high shear stress associated with flushing protocols, combined with in-situ reactions.[…] One study reported increases in iron, copper, particles, and turbidity, and bacteria (as much as 19X) following a pressure shock.
Of interest, the article cautions that water quality should also be evaluated for buildings that are being re-purposed as medical facilities, especially if showers are to be installed because of the risk of Legionella; according to the Centers for Disease Control and Prevention (CDC) Legionella can become a health concern "when [people] breathe in small droplets of water in the air that contain the bacteria", which can occur during a shower.