PEX Tubing Passes California Environmental Review

Cross-linked polyethylene tubing, known as PEX, has become a common choice for water-supply piping in buildings, holding 40% of the nationwide market, according to one manufacturer. It has not been allowed statewide in California, however, due in part to various environmental concerns. Following the completion of an environmental impact report, the California Building Standards Commission has approved PEX for the California Plumbing Code, effective August 2009. The report focuses on the concern that the breakdown of a catalyst used in some polyethylene cross-linking processes could allow harmful substances, including MTBE, a chemical whose use as a fuel additive has raised health concerns, to leach into drinking water (see EBN Apr. 2007).

Testing by NSF International found that new PEX piping does leach MTBE, but at concentrations well below 100 micrograms per liter the chemical does not pose a health risk, according to NSF. The testing found that MTBE levels in drinking water declined significantly within 90 days, further reducing any risks. The report is available at http://www.bsc.ca.gov/pex.htm.