Being well-hydrated is one of the keys to good health and water quality is critical for any healthy building strategy. Overall water quality in a building may be determined by measuring some basic indicators—namely, turbidity, total dissolved solids, and total coliform.
Turbidity is an indicator of how transparent the water is. It is governed by the amount of suspended particulates (i.e., dirt) present in water.
Total dissolved solids are an indicator of everything in the water besides actual water itself (e.g., minerals, salts, and organic matter).
Coliform bacteria, which is present in human and animal feces, can serve as a proxy to indicate when harmful pathogens may be present in water.
Additionally, there are relatively new water quality issues emerging such as the so-called “Forever Chemicals” that can now be found in the drinking water of millions. (If you want to venture down the PFAS rabbit hole, start with Sean Grady's Environmental Transformation podcast interview with Robert Bilott, the attorney depicted in the movie Dark Waters and author of the book Exposure.
Facility managers should also be mindful of localized issues in areas where industrial waste could work its way into nearby bodies of water.
The water arriving to your building is usually ok (not always), but then...
In the U.S., the EPA's National Primary Drinking Water Regulations set maximum levels for various contaminants. The regulations are generally effective in ensuring that the water delivered to buildings is safe. However, once water passes the building’s meter, all bets are off. A number of localized threats to water quality can come into play. Broadly considering our aging building stock, two threats in particular are Legionella and lead contamination. We frequently hear horror stories of Legionella outbreaks. This can be helped by managing water temperature, limiting stagnation, ensuring an adequate level of residual disinfectant is present, and controlling the water’s pH level, which is a measure of how acidic/basic the water is. We also hear about lead contamination downstream of the water districts—from the historic uses of lead in pipes, solder, fittings, and fixtures. Again, the pH level is critical.
A building's water quality is a moving target. It can be best ensured by annual testing at point-of-use taps and verifying that water meets the standards set the EPA's Safe Drinking Water Act (SDWA). Test for Legionella concentrations in cooling towers at least quarterly. Monitorization is key. Monitor water temperature, residual disinfectants, and pH levels. Public water systems contain small quantities of chlorine, which serve as disinfectants. According to the CDC, the minimal quantity does not cause harmful health effects and provides protection against waterborne disease outbreaks. As illustrated in the figure below, if the pH is too high, the residual chlorine in the water loses biocidal properties; if the pH is too low, then lead leaching and corrosion can more readily occur. That reverse osmosis filter at each drinking water source is not a bad idea either.
A collective and concerted effort will go far toward ensuring that your healthy building also has clean water.
Figure: Chlorine disassociation curve at varying pH. Chlorine exists in drinking water as a balance of hypochlorous acid (HOCL) and hypochlorite ion (OCL). The EPA's recommended pH range is also noted. Adapted from J. Allen and J. Macomber, Healthy Buildings: How Indoor Spaces Drive Performance and Productivity (Cambridge, MA: Harvard University Press, 2020).