If you are concerned that your drinking water may be contaminated with lead, letting it run for a minute or two, as is commonly recommended, is not a reliable way to flush out contaminants, according to a study from Louisiana State University, published in the International Journal of Environmental Research and Public Healthin July 2018.
Researchers did tests in 376 homes in New Orleans and found that in more than half of them, lead levels actually increased after the cold water ran for two minutes. Elevated lead levels didn’t decline significantly until after the water ran for six minutes, and even then reductions were often not substantial.
Lead gets into water via plumbing (old service lines, pipes, solder, and brass faucets) and is especially dangerous for children and pregnant women.
If you are uncertain about your tap water, get it tested, and if high lead levels are found, replace old pipes and plumbing that may be leaching lead, or at least use water filters certified to reduce lead. Your local health department or water company may offer free testing. For more guidance about lead in drinking water, go to the CDC website or EPA website.
This article first appeared in the UC Berkeley Wellness Letter.
Also see Hidden Lead in Your Home.