In 2015, Flint, Michigan drew attention when tests showed extremely high lead levels in its drinking water. This issue stemmed from the city switching its water source to the Flint River in the previous year, which led to corrosive water damaging aging lead pipes, thereby exposing many residents to lead contamination. This situation created a human health crisis that still affects Flint residents today. However, Flint’s scenario is not isolated.
According to the Environmental Protection Agency (EPA), approximately 9.2 million service lines supplying drinking water to homes and businesses in the U.S. are made of lead. The federal government has prioritized replacing these lead pipes and initiated several efforts, including the 2021 Infrastructure Law, which allocated $15 billion over five years for this purpose. Additionally, the EPA is proposing a mandate for the removal of lead pipes throughout the U.S. within a decade.
However, the agency has not addressed what should replace lead. Our research focuses on water policy and chemistry, particularly concerning plastics, new contaminants, and ensuring equitable access to clean water. We are concerned about the widespread use of plastic as a substitute for lead pipes. The issue of lead pipes is especially prevalent in cities with large low-income populations. Seven out of the ten U.S. states with the most lead service lines are located in the Great Lakes region. Our findings indicate that the new federal funds will cover less than 20% of the cost needed to replace known lead pipes in that area alone.
These cities might inadvertently introduce new environmental health hazards. There is no safe level of lead exposure for humans. In children, lead exposure can harm organs and brain development, leading to reduced intelligence, behavioral issues, and learning difficulties. Adults are also affected, as even minimal lead exposure can result in kidney issues and high blood pressure. A recent study suggested that 170 million U.S. adults encountered high levels of lead as young children. In 1986, Congress amended the Safe Drinking Water Act to ban the use of lead pipes in the installation or repair of any public water system, home, or business that provides drinking water.
However, many communities already had lead pipes that were expected to last for many more years, and replacing them is costly. The EPA estimates that replacing each lead service line from a municipal water main to a residence costs an average of $5,066. Copper, iron, and plastic are common alternatives for lead pipes, with plastic, specifically polyvinyl chloride (PVC), gaining popularity due to its lower initial cost. Nevertheless, all pipe materials can present issues over time, and plastic pipes pose potential hidden costs in drinking water systems, raising serious health concerns. PVC pipes first appeared in U.S. water systems in 1955 and became common in the 1970s, with other plastic types like cross-linked polyethylene (PEX), high-density polyethylene (HDPE), and chlorinated polyvinyl chloride (CPVC) also used.
Studies have shown that plastic pipes can attract metals and leach chemicals, including micro- and nanoplastics, which can exacerbate kidney disease. Researchers have documented the degradation of plastics and the release of chemicals from plastic polymers and additives over the last decade. A 2023 study found that both the material and age of pipes can contribute to releasing microplastics into drinking water. Biofilm, which consists of microorganisms accumulating on surfaces in contact with water, can also cause pipe problems by collecting heavy metals like lead, which then gradually enter the water supply. This buildup is problematic in any pipe, but evidence suggests that organic substances from polymer-based pipes might encourage biofilm growth, and plastic materials might facilitate pathogen concentration in pipes.
More research is needed to determine if biofilm is a greater concern in plastic pipes. While PVC and other plastic pipes are expected to last a long time, they have demonstrated durability issues. A study in the Netherlands’ waste water systems, which have extensively used plastic pipes since the 1970s, found issues like deformations, leaks, and root intrusion. U.S. cities that installed plastic water pipes have seen similar problems. Prescott, Arizona, started using PVC pipes in the 1980s and began noticing durability issues in the 1990s. In 2023, Prescott’s mayor announced a shift from PVC to ductile iron due to concerns about longevity and leaks. Hamilton, Ohio, reported early failures of HDPE service lines and water mains after just 20 years, despite HDPE’s expected 80-year lifespan, prompting a switch to iron and copper pipes.
Plastic is also susceptible to fire damage, melting and releasing harmful chemicals when exposed to high heat. In 2023, a fire in Lahaina, Hawaii, damaged plastic water pipes, lowering water pressure when Maui firefighters needed it most. This led to warnings that plastic pipes might contaminate the water supply by leaching dangerous chemicals. Loss of pressure can create a vacuum that draws chemicals and bacteria into the water system. Fires can also cause plastics to emit harmful chemicals. In California, water testing after wildfires in 2017 and 2018 revealed that water systems were contaminated with volatile organic compounds, such as benzene, a carcinogen. With billions in federal funding available, communities are currently deciding whether to invest in plastic pipes or alternatives for lead replacements. This is a significant undertaking.