A Vote to Reduce Plumbing Flow Levels Could Come With Health Risks

Washington State is considering a bill that would require water flow rates in plumbing fixtures below what’s required by federal WaterSense levels. That could endanger public health, cautions Kerry Stackpole of Plumbing Manufacturers International.

Written by Kerry Stackpole Published on Read time Approx. 2 minutes
A low-flow faucet at Pitzer College in California.Irfan Khan/Los Angeles Times via Getty Images

Washington State legislators want to do whatever they can to save water.

As a result, the Washington State House of Representatives has passed ESHB 2327, a bill that would reduce plumbing flow rates below federal WaterSense levels. The state’s Senate is now considering the bill, with a vote expected soon.

“Not so fast!” say manufacturers whose job it is to assure the safety of the water-efficient faucets, showerheads, toilets and urinals that the bill addresses. Don’t go further than WaterSense levels, they say.

These manufacturers are expressing their concerns to state senators because lowering flow rates below WaterSense levels may increase the chance of unintended consequences that could endanger public health, according to scientists who study waterborne pathogens.

These scientists – including Marc Edwards, a Virginia Tech professor who was among the first to recognize the lead-tainted water crisis in Flint, Michigan – have hypothesized that there may be a link between low flow rates and outbreaks of waterborne disease, including the most common one, Legionnaires’ disease. Washington State saw 72 cases of it in 2016, resulting in 10 deaths, according to a report in the Seattle Times.

Plumbing standards, such as maximum allowable flow rates, can make the eyes glaze over, but it’s worth paying attention to them now because water safety may be at stake.

Plumbing products meeting WaterSense criteria are certified to be at least 20 percent more water-efficient than those meeting federal and current Washington State standards. WaterSense products also meet high performance and safety standards. But going below WaterSense levels, as proposed by ESHB 2327, may cause product performance issues, as well as public health risks. Keeping water in pipes longer and increasing water age can dissipate disinfection agents and foster the growth of biofilms that amplify the growth of opportunistic waterborne pathogens in plumbing systems, according to an Environmental Protection Agency study.

The only state with flow rates below WaterSense levels is California, which reduced them in response to severe drought. The reduced indoor water usage caused by these lowered rates may have an adverse impact on water infrastructure, water system operation and maintenance costs, and on public health, according to a white paper published in November 2017 by organizations including WaterReuse California, the Water Research Foundation and the Association of California Water Agencies.

In addition, the EPA is funding two studies measuring the potential impact between low flow rates and waterborne disease outbreaks and other water quality problems. The first, with Drexel University, is entitled “Water Conservation and Water Quality: Understanding the Impacts of New Technologies and New Operational Strategies.” The second, with Purdue, Michigan State and San Jose State, is “Right Sizing Tomorrow’s Water Systems for Efficiency, Sustainability and Public Health.”

A recent EPA webinar indicated that both projects hypothesize that low flow rates have contributed to outbreaks of waterborne diseases and other water quality problems in building plumbing systems.

All of these reasons are why Plumbing Manufacturers International – the association representing these plumbing product manufacturers – urges the Senate to consider going to WaterSense levels rather than going below them, at least until the impact of reducing flow rates even further can be studied.

Washington’s flow rates are now in line with federal regulations. Reducing them to WaterSense levels would be a significant reduction – and a safer one – than going below WaterSense levels.

The views expressed in this article belong to the author and do not necessarily reflect the editorial policy of Water Deeply.

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