Concerns Over Plastic Pipes as Lead Pipe Replacements in U.S. Water Systems

Flint, Michigan, made headlines in 2015 when tests revealed dangerously high levels of lead in its drinking water. The city had switched its water supply to the Flint River a year earlier, and the corrosive water damaged old lead pipes, exposing thousands of people to lead contamination.

The result was a humanitarian health crisis whose effects are felt to this day. Flint was just the tip of the iceberg.

The Environmental Protection Agency estimates that 9.2 million service lines delivering drinking water to homes and businesses in the United States are made of lead. The federal government considers replacing these lead pipes a top priority and has launched a variety of initiatives to help, including the Infrastructure Act of 2021, which allocated $15 billion over five years to replace lead pipes.

The Environmental Protection Agency now proposes eliminating lead pipes across the United States within ten years. However, the agency has remained silent on what should replace the lead.

We study water policy and water chemistry, with a focus on plastics and emerging pollutants, as well as on equitable access to clean water. We see concerns about a popular alternative material to lead pipe: plastic.

The buried legacy of lead pipes is concentrated in cities with large populations of low-income residents. Seven of the 10 states with the most lead service lines are Great Lakes states, and our research shows that new federal funding would cover less than a fifth of the cost of replacing known lead pipes in that region alone. These cities could unwittingly pose new environmental health risks.

The problem with lead pipes

There is no level of lead exposure considered safe for humans.

In children, lead exposure can affect their organs and brain development, causing reduced intelligence, behavioral disorders, and learning problems. Adults are at risk, too. Even low exposure to lead can cause kidney problems and high blood pressure. A recent study estimates that 170 million adults in the United States were exposed to high levels of lead in early childhood.

In 1986, Congress amended the Safe Drinking Water Act to prohibit the use of lead pipes in the installation or repair of any public water system or home or business that supplies drinking water.

But many communities already have lead pipes that they expect to last decades longer, and replacing them is expensive. The Environmental Protection Agency estimates that replacing each lead service line from the city’s main water supply to a home costs an average of $5,066.

Copper, iron, and plastic are common alternatives to lead pipe. Plastic, especially polyvinyl chloride, or PVC, is an increasingly popular choice. Plastic tends to have a lower initial price than other products.

However, while most piping materials do have problems over long periods of time, there are potential hidden costs to using plastic piping in drinking water systems that raise serious questions and health concerns.

The Hidden Health Costs of Plastic

One type of plastic, PVC, was first used in U.S. water systems in 1955 and became widely used in the 1970s. Other types of plastic pipe include cross-linked polyethylene (PEX), high-density polyethylene (HDPE), and chlorinated polyvinyl chloride (CPVC).

Scientific studies have shown that plastic pipes can attract minerals and leach chemicals, microplastics and nanoplastics, which are known to aggravate kidney disease.

Over the past decade, researchers have documented the degradation of plastics and the release of chemicals from plastic polymers and additives in plastics and microplastics. A 2023 study found that pipe material and age can contribute to the release of microplastics into drinking water.

Biofilms—a layer of microorganisms that builds up on surfaces that come into contact with water—can also cause problems in pipes. A 2023 study showed how these biofilms can collect heavy metals, such as lead, which can then be slowly released into the water over time. This buildup is a problem in any pipe. However, some studies have reported that the release of organic matter from polymer-based pipes may promote biofilm growth, and plastics may enhance the ability of pathogens to accumulate in pipes. More studies are needed to evaluate whether biofilms are a more significant concern in plastic pipes.

Durability concerns

Although PVC and other plastic pipe materials have a long lifespan, they have had problems with durability.

A study of Dutch wastewater systems, where plastic pipes have been widely used since at least the 1970s, found distortions, leaks, and root infiltration. Some cities in the United States that have installed plastic drinking water pipes have experienced similar problems.

The city of Prescott, Arizona, began using PVC pipe in the mid-1980s, and began seeing durability issues in the 1990s. In 2023, the mayor of Prescott announced a switch from PVC to ductile iron due to longevity and leakage issues.

The city of Hamilton, Ohio, began experiencing premature failure of its HDPE service lines and water lines after only 20 years, even though the life span of HDPE is estimated at about 80 years. Now the city is switching to using iron and copper.

Fire can melt plastic, releasing toxic chemicals

Plastic is also susceptible to fires. Studies have found that when PVC pipes are heated to high temperatures, they can melt and release harmful chemicals.

The 2023 fire in Lahaina, Hawaii, damaged plastic water pipes, contributing to low water pressure when Maui firefighters needed it most. In the aftermath, residents were warned that plastic pipes could contaminate water supplies by leaking dangerous chemicals. Loss of pressure can create a type of vacuum that sucks chemicals and bacteria into water systems.

Heating during fires can also release harmful chemicals from plastics. Water tests in California communities affected by wildfires in 2017 and 2018 found water systems contaminated with volatile organic compounds such as benzene, a carcinogen.

Public protection

With billions of dollars in federal funding available, communities are now deciding whether to invest in plastic pipes or other materials as alternatives to lead. This is a historic commitment.

However, we believe more research needs to be done on the potential impacts of plastic to better understand the short- and long-term risks to human health and the environment. All factors must be taken into consideration: health, durability, longevity and fire concerns. The initial price is not always an indicator of hidden costs.

Rajpreet Grewal, Water Policy Specialist, University of Wisconsin-Milwaukee; Laodong Gu, Professor of Aquatic Biochemistry, University of Wisconsin-Milwaukee, and Melissa Scanlan, Professor and Director of the Water Policy Center, College of Freshwater Sciences, University of Wisconsin-Milwaukee

This article is republished from The Conversation under a Creative Commons license. Read the original article.