Recent tests show that Washington water is safe from lead contamination (May 5, 2005)

Recent testing of the City of Washington water system show that city water is safe from lead and copper contamination.

Lead and copper can enter drinking water by leaching from plumbing systems inside water customers’ homes. At greatest risk are homes equipped with copper pipes and lead fittings commonly used in buildings constructed up to 1986.

Every three years the City of Washington tests for lead and copper content in drinking water. The city has gone to great length to identify homes throughout the water system with the highest likelihood of having this type of plumbing in order to obtain a “worse case” glimpse of lead and copper levels in the entire system.

The most recent tests, conducted in October 2004, showed lead levels in all samples well below 15 parts per billion – the level at which the federal government requires public education efforts to reduce the risk of lead poisoning and alterations in treatment methods to reduce lead levels. Of the 30 samples tested, 29 showed only the lowest detectable level of lead at less than 3 parts per billion. The level of lead in the 30th sample was only 3 parts per billion.

While the city conducts this sampling in accordance with a state approved sampling plan, resources are not currently available to sample sites less likely to contain contamination. Customers who desire to have their homes or businesses tested individually should contact an independent water testing company.

Even though the source of lead contamination in drinking water most likely originates in the home and not the public treatment and distribution system, water systems can take measures to reduce the likelihood of metals leaching from plumbing systems into the water. One preventative measure that the City of Washington takes is maintaining a water supply that is not completely “soft.” Completely soft water has a hardness content of 0 milligrams per liter (mg/l) of CaCo3 (calcium carbonate) or hardness. Soft water is corrosive and can cause pipes to break down and cause increased levels of lead and copper in the water at people’s homes. In contrast, the city maintains a medium hardness level of 60-70 mg/l in the water system. Water with this level of hardness is less corrosive to pipes and fixtures.

Another precaution the city takes to prevent lead and copper from leaching into the water is adding a corrosion inhibitor to the water as part of the treatment process. The inhibitor actually coats the pipe and creates a barrier between the water and the pipe.

There also are steps that water customers can take in their homes to reduce the potential for lead contamination in their drinking water.

• Lead levels will be highest in water that has been sitting still in pipes for a while before flowing. Allow water that has been sitting still in pipes for extended periods, such as overnight or several hours during the day, to flow freely for 1 or 2 minutes before using any for drinking, bathing or cooking to flushes out any accumulated lead and copper.
• Lead and copper leach more easily into hot water than into cold water. Use water from the cold water tap only for cooking and making beverages.
• As an extra precaution, periodically remove and clean screens that are inside sink faucets. Screens may capture bits of lead solder that have broken loose from the pipes and expose your drinking water to lead contamination every time you turn on the faucet.