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This article written by NSF’s Marcos Bensoussan and Fernando Fonseca was originally published in Infra FM magazine in Portuguese and is reprinted with permission here in English.
Combating the new coronavirus (SARS-CoV-2), which causes the respiratory disease known as COVID-19, has required some changes in our routine in order for us to decrease its proliferation. Avoiding touching on your face, routinely washing your hands and cleaning objects, and coughing and sneezing by covering your mouth with a tissue or with the inside of your elbow are just some of these control measures.
Community actions such as canceling classes, restricting trade, closing buildings to the public and migrating people from the office to work in their homes have left an enormous number of buildings throughout the world underutilized or practically unused. Consequently, water consumption drops in these buildings.
With lower water consumption, the building water system will have low to no flow in its piping systems and storage tanks. The increased time between when water enters the system and when it is consumed or discarded causes areas of stagnant water. This will have negative impacts on water quality in the building such as a change in color and taste, increased corrosion processes and, mainly, microbiological growth and biofilm formation.
The longer the standing time of water in the building system, the longer bacteria and microorganisms will have to proliferate and concentrate to levels that can generate infections and health problems for the users of the systems. Several types of diseases may have an increased risk in a system with low-flow or standing water, including gastrointestinal infections, severe pneumonias (such as those caused by Legionella bacteria) and skin infections (such as those caused by fungi and Pseudomonas).
To make the water system safer during situations of low water demand in buildings, it is important to maintain:
These simple measures can renew the water in building systems and, thus, reduce the impact of microbiological growth and other problems in situations of low demand. They are efficient and can be applied to practically all types of building systems, but they are not specific enough to keep the water completely safe for normal consumption and use.
Other hazards and hazardous conditions can exist in a building’s cold and hot water systems, as well as in several other systems such as cooling systems. For this reason, it is always recommended that every building develop a water management program based on a site-specific risk assessment that considers the potential waterborne hazards in the building, including effects on human consumption, aspiration and contact with skin and mucous membranes. Only then can we have a secure system during periods of both low flow and normal operation.
Marcos Bensoussan is Director, Latin America, Water Division at NSF, and Fernando H. Fonseca is Technical Manager, Water Division at NSF Health Sciences. Both are based in NSF’s Sau Paulo, Brazil location.