Protecting Public Health and the Environment.

Lead in Drinking Water

Lead is a toxic metal that was commonly used in consumer products such as gasoline and paint before it was discovered that it is harmful to human health. We now know that, if inhaled or swallowed, lead can build up in the body over time and cause serious damage to the brain, kidneys, nervous system, and red blood cells.

The problem of airborne lead exposure has been largely resolved in most of the United States as a result of the phase-out of leaded gasoline. Nowadays, lead exposure is more likely to come from soil and dust (indoors and outdoors), food contaminated in the air or in food containers, and water (from the corrosion of plumbing).

Impacts of Exposure to Lead

Exposure to lead is most dangerous for young children (six and under) and infants because their bodies are growing quickly. A dose of lead that would have little effect on an adult could have a big effect on a small body. Research suggests that the primary sources of lead exposure for most children are deteriorating lead-based paint, lead-contaminated dust, and lead-contaminated residential soil. On average, however, it is estimated that lead in drinking water contributes between 10% and 20% of total lead exposure in young children. Lead exposure in drinking water may be as high as 60% in infants whose diet consists mostly of liquids made with lead-contaminated water.

Lead and Drinking Water

The limited source of lead exposure from your home's water is mostly likely pipe or solder in your home's own plumbing. The most common cause is corrosion, a reaction between water and lead pipes or solder. Lead levels are likely to be highest if your home has faucets or fittings of brass that contain some lead, or your home or water system has lead pipes or copper pipes with solder that contains lead.

Lead can be present in school drinking water as well where water often remains stagnant in plumbing—overnight, over a weekend, or during a vacation. The amount of lead depends on the materials from which the system was constructed and the corrosivity of the water. The age of the building does not seem to matter when addressing lead concerns and even new plumbing fixtures can leach lead into the drinking water.

In 1986, the federal Safe Drinking Water Act was amended to require the use of lead-free pipe, solder, and flux in the installation or repair of any public water system or any plumbing in a residential or nonresidential facility connected to a public water system. Although very small amounts of lead may still be used, permissible lead content was dramatically reduced.

How to Reduce Exposure to Lead in Drinking Water

Flush pipes before drinking.

The longer the water stands idle in the pipes, the more lead it can absorb. Do not drink or cook with water that has been in your plumbing for more than 6 hours—overnight, for example, or while you're at work. Flush your pipes by letting the cold water faucet run until you feel the water get colder, at least 30 to 60 seconds. (To prevent wasting this water, use it for watering plants or washing dishes.) Boiling water does not remove lead.

Consume cold water only.

Hot water is likely to contain higher levels of lead. If you need hot water for cooking or drinking, use cold water and heat it. Important: Do not use hot water for making baby formula!

Have water tested.

Because you cannot see, taste, or smell lead dissolved in water, the only way to ensure your household water does not contain harmful quantities of lead is to have it tested by a laboratory. As it is possible to inadvertently bias lead results through the sample collection process, care should be taken to closely adhere to sampling requirements outlined by the laboratory. Contact your local drinking water system or health department for information and assistance.

Some treatment devices can reduce the amount of lead in drinking water. Check the product literature to ensure it has been certified by the National Sanitation Foundation for lead removal.

Lead and Copper Site Selection

The Lead and Copper Rule (LCR) requires all community and nontransient, noncommunity water systems to sample at locations that may be particularly susceptible to high lead or copper concentrations in accordance with IDAPA The LCR establishes a tiering system for prioritizing sampling sites. A materials evaluation is required to help classify sampling sites into tiers. Most existing water systems conducted this survey in 1992 but will benefit from conducting the survey again as materials may have changed. New water system owners and operators must perform a materials evaluation prior to lead and copper tap monitoring. The Lead and Copper Sample Site Selection Form (link at right) defines the monitoring requirements and tiering system for prioritizing sampling sites and includes a site selection certification form for submittal to DEQ.