How Leaching Affects Water Quality

When selecting pipes for drinking water systems, it’s critical to understand and evaluate the effect materials can have on water quality and human health. Clean water can become contaminated as it travels from a distribution facility, through a complex maze of pipes, and finally through a faucet. One lesser-known risk is generating increased concern – substances used to manufacture pipes can leach from the pipe wall and enter water supplies. The process can be triggered by corrosive (low pH) water sources and it can also occur as a result of using low-quality piping products.

What Leaches?

The amount and type of leaching depends on the pipe type. For example, plastic pipe may leach a number of chemicals as the pipe is worn down by the nonstop flow of water (especially hot water). This includes polyethylene (PE)w, cross-linked polyethylene (PEX), high-density polyethylene (HDPE), polypropylene (PP), chlorinated polyvinyl chloride (CPVC), and polyvinyl chloride (PVC).

Comparatively, copper is a natural element and copper piping is 99.9 percent pure copper. If a water source is highly corrosive (around 3 – 5 percent of American water sources), copper particles can enter the water. This is a concern for individuals suffering from Wilson’s Disease, a genetic affliction where the body cannot process copper.

Copper and Plastic Leaching

The chart below shown the seven common piping materials, what they are known to leach, and what effects these substances can have on human health.
Copper Copper Gastrointestinal distress, nausea and vomiting. Copper is commonly used for service lines, the pipes connecting a home and business to the underground piping network. Copper is also a common in-the-building or high-pressure gas piping material because its durability and heat resistance.
Polyethylene (PE) Benzene, trichloroethylene, dibutyl phthalate Cancer PE can be used for water mains, which are large, underground pipes that carry water to area; service lines draw water from mains. PE is also used for sewer systems.
Cross-linked polyethylene (PEX) Benzene, toluene, ethyl-tert-butyl ether (ETBE), trichloroethylene, pyridine, carbon disulfide Cancer, human toxin, reproductive toxin PEX can be used for service lines, reclaimed water systems and chilled water.
High-density polyethylene (HDPE) Bezene, ethylbenzene, naphthalene, toluene, trichloroethylene, carbon disulfide Cancer, human toxin, reproductive toxin HDPE can be used for water mains, sewer mains, and storm water drainage.
Polypropylene (PP) Toluene Human toxin PP can be used for chemical drainage applications.
Chlorinated polyvinyl chloride (CPVC) Ethyl acrylate, formaldehyde, epichlorohydrin, carbon tetrachloride, chloroform, vinyl chloride, carbon black, Di (2-ethylhexyl) phthalate (DEHP), dibutyl phthalate, 1,3-butadine. Cancer, human toxin, reproductive toxin CPVC can be used for water service lines and drainage systems.
Polyvinyl chloride (PVC) Ethyl acrylate, formaldehyde, benzene, ethylbenzene, toluene, epichlorohydrin, ethylene dichloride (1,2 – Dichloroethane), bromoform, carbon tetrachloride, chloroform, bromodichloromethane, dichloromethane, tetrachloroethylene, vinyl chloride, carbon black, Di (2-ethylhexyl) phthalate (DEHP), 1,3-butadiene. Cancer, human toxin, reproductive toxin PVC can be used in some instances of in-the-building use, but it cannot be used in hot water applications, which will cause the pipe to warp and even fail.  PVC may be used for drainage lines from sinks, toilets and bath tubs.

*This was compiled by referencing California’s Safe Drinking Water and Toxic Enforcement Act and a recent study that evaluated what chemical substances leach from plastic piping systems.  

While each type of plastic is different in its own way, all six variants have shown a tendency to leach dangerous chemicals, in some cases only a few months after installation. These substances are registered or suspected toxins with a variety of health effects, from reproductive harm to developmental impacts. Beyond these established hazards, 74 additional chemicals that leach from plastic pipe are unstudied or unregulated, with as-yet-unknown health effects.

Well-informed Piping Decisions

When making piping material decisions, be aware of what effect leached substances can have on water quality and human health. The use of low quality products manufactured with complicated chemical blends can result in the chemical contamination of water supplies. For more information on leaching, visit our blog

Study: Majority of Leached Substances are Carcinogenic, Toxic, or Unregulated.