Copper, iron and plastic are all common replacement materials for lead pipes. Plastic, particularly polyvinyl chloride or PVC, is an increasingly popular choice. Plastic tends to have an initial price tag that is lower than the others.

However, while most pipe materials have issues over long periods of time, there are potential hidden costs to using plastic pipes in drinking water systems that are raising serious questions and health concerns.

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

Scientific studies have shown that plastic pipes can attract metals and leach out chemicals and micro- and nanoplastics, which are known to exacerbate 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 in drinking water.

Biofilm – the layer of microorganisms that build up on surfaces in contact with water – can also cause problems in pipes. A 2023 study showed how this biofilm can collect heavy metals, such as lead, which can then be slowly released into the water over time. This accumulation is a problem with any pipe. Some studies, however, have reported that the release of organic substances from polymer-based pipes may promote the growth of biofilms, and plastic materials may promote the ability of pathogens to accumulate in pipes. Further studies are needed to evaluate whether biofilm is a more significant concern in plastic pipes.

While PVC and other plastic pipe materials have a long life expectancy, they have had durability problems.

A study conducted in Dutch wastewater systems, where plastic pipes have been extensively used since at least the 1970s, found deformations, leaks and root intrusion. Some cities that installed plastic drinking water pipes in the U.S. have encountered similar problems.

Prescott, Arizona, started using PVC plastic pipes in the mid-1980s and began seeing durability issues in the 1990s. In 2023, citing problems with longevity and leaks, Prescott’s mayor announced a switch from PVC plastic to ductile iron.

Hamilton, Ohio, started seeing premature failures of HDPE service lines and water mains after only 20 years, despite HDPE’s estimated life span of 80 years. The city is now switching to iron and copper.

...continued