Northwest NEWS

May 29, 2000

Local News

Health risks of lead in drinking water

by Bronwyn Wilson, staff reporter

   One home out of 15 tested in the Woodinville area may have an unsafe level of lead in the water, according to information supplied by the Woodinville Water District.

   A safe level is not to exceed 15 parts per billion (ppb). Although most homes have very low levels of lead in their drinking water, some homes in the community may have lead levels above the United States Environmental Protection Agency (USEPA) action level of 15 ppb.

   Lead is a toxic metal and can be harmful if ingested or inhaled. Lead and copper can leach into drinking water from plumbing systems containing copper plumbing, lead-based solder, brass fixtures, or some types of zinc coatings used on galvanized pipes and fittings. Metals leach into the plumbing when water has not been used and sits stagnant in the pipes for six hours or longer.

   Lead-contaminated drinking water is most often a problem in houses that are either very old or very new. Homes built prior to the King County lead solder bans could be at risk for lead if lead-based solder was used in building plumbing systems. Brass fixtures, regardless of age, generally contain some lead.

   Up through the early 1900s, it was common practice, in some areas of the country, to use lead pipes for interior plumbing. Plumbing installed before 1930 is most likely to contain lead. Also, scientific data indicates that newer homes have a risk of lead contamination with levels decreasing as a building ages. This is because, as time passes, mineral deposits form a coating on the inside of the pipes (if the water is not corrosive). The coating insulates the water from the solder. It usually takes five years for the coating to form; before then, the water is in direct contact with the lead.

   The Water District is evaluating methods to minimize lead in drinking water. The District will replace each lead service line that it controls if the line contributes lead concentrations of more than 15ppb after completing the comprehensive treatment program. Under Federal law, the Woodinville Water District is required to have a program in place to minimize lead in drinking water. This program includes corrosion control treatment, source water treatment, and public education.

   Regarding public education, Deborah Rannfeldt, Public Information Coordinator for the Woodinville Water District explained, "We provide information about lead and copper in our Water Quality Report, which is mailed to homes the first week of May, National Drinking Water Week. On our website and in December, we send out a detailed brochure on copper and lead in our (billing) statements to meet the public education requirement."

   Suggested steps to reduce exposure to lead in drinking water include allowing the tap water to run from the tap before using it for drinking or cooking. The longer water resides in the home's plumbing, the more lead it may contain. Flushing the tap means running the cold water faucet until the water gets noticeably colder, usually about 15-30 seconds. If possible, use the flushed water for watering plants or washing dishes. Never start with hot tap water for cooking, drinking, or making baby formula, because hot water dissolves metals faster. Start with cold water, then heat it up.

   Customers with questions or who want to have their water tested (for a fee) may call the District's Water Quality Officer, Tim Cantwell, for a list of independent testing laboratories in the area. His number is 483-9104, ext. 325. For further information, visit