Project focuses on reducing pathogen threat in low-flow water systems

Low-flow building water systems pose potential health hazards because they may cause an increase in disease-causing organisms and harmful chemicals. A new project led by Purdue University and joined by MSU researchers strives to help solve the problem.

Jade Mitchell

EAST LANSING, Mich. – Low-flow building water systems designed to conserve water pose potential health hazards because they may cause an increase in disease-causing organisms and harmful chemicals.

A new Environmental Protection Agency (EPA)-funded project led by a Purdue University scientist, and joined by several Michigan State University researchers, strives to help solve the problem.

“The increasing occurrence of low flows in water distribution systems and building plumbing presents an emerging health concern. Opportunistic pathogens more easily multiply under low-flow conditions,” said Andrew Whelton, an assistant professor in Purdue’s Division of Environmental and Ecological Engineering and Lyles School of Civil Engineering. “Building designers, managers, and health officials need better information and models to predict health risks in plumbing systems found in all sorts of buildings, from schools, to homes, to healthcare facilities.” 

The organisms include the bacterium Legionella pneumophila, which causes Legionnaires disease; the brain-eating amoeba Naegleria fowleri; Pseudomonas aeruginosa, an antibiotic-resistant pathogen associated with serious illnesses; and Mycobacterium avium, which causes respiratory illness, especially in immunocompromised people.

“These opportunistic pathogens continue to cause waterborne disease outbreaks across the country,” said Whelton, the project lead. “In fact, Legionella remains the most identifiable cause of waterborne disease in the United States.”

In addition to Whelton, the team includes co-principle investigators:  Jade Mitchell, an assistant professor in MSU’s Department of Biosystems and Agricultural Engineering;  Joan Rose, the Homer Nowlin Chair in Water Research at MSU and the 2016 Stockholm Water Prize Laureate; Janice Beecher, director of the Institute of Public Utilities Policy Research & Education at MSU; A. Pouyan Nejadhashemi, an associate professor at MSU’s Department of Biosystems and Agricultural Engineering; and  Juneseok Lee, an associate professor and California Water Service Co. Chair Professor in San Jose State’s Department of Civil and Environmental Engineering. Other MSU collaborators include Erin Dreelin and Matt Syal, and MSU post doc Mohammad Abouali.

“The research announced yesterday will guide decision makers as they design, renovate, or manage plumbing systems to provide safe and clean drinking water,” said Thomas Burkey, agency science adviser and deputy assistant administrator of EPA’s Office of Research and Development.

“Lower usage and lower flows in water systems are raising engineering, economic, and public health issues, so an interdisciplinary approach is needed,” Beecher said. “This research is especially timely in terms of the urgency of optimal infrastructure investment with a focus on ensuring safe drinking water."

The researchers will work to better understand and predict water quality and health risks posed by declining water usage and low flows. The group is funded with a $2 million grant from the EPA. The three-year project, which begins this month, also will be funded with $1.1 million from non-federal sources including Whirlpool Corp., Citizens Energy Group, and the Avon Community School Corporation, among others.

“Our research will be used to guide risk-based decisions in engineering design and public policy in order to prevent waterborne disease outbreaks,” said Mitchell. “Our collaborative multidisciplinary team will evaluate the drivers of water conservation practices and trends, collect water samples for chemical and microbial analysis from several residential and commercial buildings and ultimately generate models that predict water quality impacts and human health risk.”

Building plumbing in the United States has been trending toward low-flow rates to conserve water, going from 4 gallons per minute (gpm) in 1994 to 0.5 gpm in today’s systems. However, while the flow rates have been reduced, the diameter of the plumbing pipes has not, causing water to age in the pipes.

“In low-flow systems, we have discovered that the water that reaches your faucet is going to be much older by the time it gets to you,” said Whelton, who described the problem during a recent conference, Dawn or Doom ’16, at Purdue. A video of the talk is available at

The researchers will develop models designed to predict water quality in plumbing systems for residential and commercial buildings, identify the most significant factors that determine the quality of tap water in these systems and water system design and operational conditions that pose increased human health risks. This information will be incorporated into a web-based “decision support system.”

“Our project goal is to better understand and predict health risks posed by declining water usage and low-flows in building plumbing,” Whelton said. “Health risks in residential and commercial buildings caused by pathogen proliferation must be minimized through water infrastructure design, operation and maintenance decisions, and codes.

The team will test hypotheses using various systems, including those in a residential home converted by experts from Purdue and Whirlpool Corp. into the most efficient domicile possible - a "net-zero" structure called the ReNEWW house; the National Conservancy’s Efroymson Conservation Center in Indianapolis, considered the most sustainable office building in the state; Avon Middle School North in Avon, Ind., and two office buildings in Michigan.

“My colleagues and I designed the project to investigate drinking water quality where people live, where they work and where they send their kids to school. This was spurred by input we received from various stakeholders, including homeowners, parents, and government officials who have contacted us in the past for assistance,” Whelton said.

Data from the research will be used to produce “predictive water quality premise plumbing models.”

The Purdue-Michigan State University-San Jose State grant application included numerous letters from people who have benefited from the advice of researchers. Letters of participation and support were submitted by the American Society of Plumbing Engineers, the United States Green Building Council, Indiana Rural Water Association, water utilities, architectural and engineering firms, as well as from researchers in Canada, Denmark, Israel, and the United States. Support also was expressed by the American Water Works Association, Healthy Building Network, National Institute for Standards and Technology, National Environmental Health Association, among others.

“We designed our project based on drinking water safety concerns from the public, industry, and government agencies. Our approach harnesses world-class expertise from industry and other academics,” Whelton said. “We have an amazing team and are eager to start working more closely with our project collaborators and supporters.”

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