Water efficiency: What is the impact of success?
There is no time to relax for a codes and standards person — 2018 kicked off with my attendance at the ASHRAE Committee meeting held in Chicago, followed by attending the American Society of Mechanical Engineers (ASME) A.112 Plumbing and Materials Equipment Committee meeting in San Diego. I participated in many discussions related to building and plumbing issues during the meetings and I noted a common thread – water efficiency.
There is a debate going on involving those who want to further decrease mandated requirements for flow rates and flush volumes for plumbing fixtures and those who want to wait while we gain additional information through sound research on the impacts of further decreasing water flows.
Today, there exists federal regulations which mandate maximum flow rates and flush volumes for plumbing fixtures. In addition, the EPA offers a voluntary testing/listing program, WaterSense, that validates and lists plumbing fixtures and appliances that meet voluntary criteria about 20% lower than the federal mandates. What is currently being pushed by some is to update model plumbing codes and product standards to require WaterSense levels. If the updates occur, the voluntary lower levels would become requirements through local adoption of the model codes and standards.
The good news
The good news is we are becoming a more water-efficient country. The U.S. Department of the Interior U.S. Geological Survey report Public Supply and Domestic Water Use in the United States, 2015 confirms urban water efficiency across the US. public withdrawals in 2015 were 7% lower than in 2010. A significant contributor to the increased water conservation is due to the plumbing product industry’s commitment to produce and sell water-efficient products that have been tested and listed under the WaterSense voluntary program. According to WaterSense, “WaterSense-labeled, high-efficiency showerheads can save at least 20% compared to standard fixtures, resulting in a potential savings of more than 2,300 gallons per household per year.” safeplumbing.org/water-efficiency/watersense
Congratulations to the plumbing industry for having such a large impact on water conservation. However, the question being asked now is, “How much is too much?” Building water delivery and removal systems are designed based on water flow rates much higher than the lower flow rates being achieved today, and we do not fully understand the impacts of the lower flow rates on the potential quality of the water in the system, the safety of the water being delivered at the outlet and the ability to properly remove the wastewater generated.
The California Association of Sanitation Agencies (CASA) published a white paper1 that sites the following potential impacts on infrastructures due to reductions in indoor water use:
- Drinking water has a longer residence in pipes leading to water-quality issues and potential compromising of public health; and
- Declining wastewater flows may increase pollutant and solids concentrations leading to blockage,
odor and corrosion in pipes.
The unanswered questions
There is research that has been completed and that is underway to try and address some of the unanswered questions and address the unintended issues surrounding lower water flows in premise plumbing systems:
- The Plumbing Efficiency Research Coalition (PERC) completed a study in 2012 and a Phase 2 study in 2016 plumbingefficiencyresearchcoalition.org/wp-content/uploads/2016/04/PERC-2-0_2-1-FINAL.pdf that evaluated the impact on lower flow devices on drain flow. It was noted in the 2012 report that, “1.28 gallon (4.8 L) and 1.6 gallon (6.0 L) test runs resulted in an orderly and predictable movement in the Test Apparatus. As a result, the PERC TC anticipates no problems with use of 1.28 gpf (4.8 Lpf) toilets (HETs) in new commercial construction. In retrofit applications, it is suggested that drainlines first be inspected for defects, root intrusions, sagging or other physical conditions that could result in clogging with lower flush volumes.” The 2016 report “does not recommend the use of 3.8 Lpf / 1.0 gpf toilets (or less) in commercial applications that have long horizontal drains and that do not provide additional long duration flows from other sources to assist with the drainline transport of solid waste.”
- Research sponsored by the International Association of Plumbing and Mechanical Engineers, the American Society of Plumbing Engineers and the Water Quality Association – Research Foundation resulted in the development of a new alternative to Hunter’s Curve when estimating water supply demand for residential buildings. This work resulted in a new “Water Demand Calculator” that better estimates pipe sizing based on current residential use patterns.
- In 2017 Drexel University was awarded a $2.5 million grant from the EPA to lead a group of researchers in a three-year project to bring together existing and experimental data on building plumbing into a risk assessment tool that can guide new water use and safety regulations.
- The discussions held at the recent ASHRAE meetings included the potential of conducting research on the impact of lower flows and changing temperature requirements on premise water systems.
- Discussions during the ASME meetings led to the formation of a task group to evaluate the unanticipated impacts on premise water systems due to lower volumes and flows.
- There is proposed legislation (HR-301) referred to as the NIST Plumbing Research Act of 2018, sponsored by Rep Matt Cartwright (D-PA). A companion Senate bill is being prepared for introduction by Senator Tammy Duckworth (D-IL). The companion bills support funding for applied research by NIST for demand-side water research leading to informed drinking water infrastructure policy.
Supporting sound infrastructure
There are other significant ways we can impact and increase water-use efficiencies that do not involve additional demands on premise water delivery systems. The American Society of Civil Engineers states in its 2017 Infrastructure Report Card that there are “an estimated 240,000 water main breaks per year in the United States, wasting more than two trillion gallons of treated drinking water.” Supporting sound infrastructure improvement funding in our water delivery systems to the premise can have a significant impact on water savings and reduced costs.
Plumbing product manufacturers and distributors are providing the marketplace a choice – plumbing
fixtures that meet federal-mandated flow and flush volumes as well as participating in the voluntary WaterSense listing program and providing plumbing fixtures that have flow and flush volumes 20% below the federal mandated levels. And through this market choice, a significant increase in water-use efficiency has been achieved. However, now is not the time to move from a volunteer system to a mandated system for fixtures delivering lower volumes or to consider even lower flow rates or flush volumes below the EPA WaterSense program. Let’s take the time to complete the needed research, carefully evaluate the results and then make sound decisions that lead to increased efficiencies while protecting the quality and safety of the water within the premise plumbing systems. And in the interim, focus on improving our existing infrastructure.