Recent media reports about lead in drinking water are prompting more people to learn if their water supply contains lead and what they can do to reduce exposure if lead is present.
According to the US Centers for Disease Control and Prevention (CDC), no safe blood level of lead has been identified for young children. Because of this, CDC recommends that all sources of lead exposure for children be controlled or eliminated.
Most lead exposure is thought to occur from chipping or peeling lead-based paint or lead-tainted dust found in homes built prior to 1978. Lead from plumbing or water distribution systems is another potential source. Lead concentrations in drinking water should be below the EPA action level of 15 parts per billion.
Over the past ten years, samples from private well water supplies submitted through UW-Extension water testing efforts revealed that five percent of “first-draw” water samples had levels of lead above the EPA lead action level. First-draw samples are designed to understand the worst case scenario; in other words, what is the highest level of lead we would expect to see after water sits in the plumbing for an extended period of time (such as overnight).
Portions of the state where groundwater is slightly more corrosive (for example, low pH, low hardness, low alkalinity) generally have a higher percentage of water samples containing lead.
Municipal water systems in Wisconsin distribute water that is typically hard water (less corrosive than soft water) or they use anti-corrosion measures that can help keep lead levels low. Under these conditions, excessively high lead levels are not expected. However low levels of lead, even sometimes above 15 parts per billion, can be possible if lead components are found in the household water system or supply lines.
Older homes are more likely to have lead containing components in the plumbing system. Prior to the 1940s, it is possible that lead piping was used as interior plumbing or for service lines. And up until 1984, lead solder may have been used to join together copper piping. The likelihood of finding significant amounts of lead in household water systems is much less in plumbing systems installed after 1984.
Reducing exposure to lead is an important health consideration, especially for households with young children or those who may be considering starting a family.
Simple measures can help
Whether your water comes from a private well or a municipal water supply, households can take some simple measures to both understand if there is lead in their drinking water and reduce exposure to lead if present.
Testing is the best way to determine if there is lead in your drinking water. When testing, consider conducting two tests—one on your “first-draw” water sample and another after flushing the water supply lines. These two tests can confirm if lead is present and whether flushing your water supply lines for two to three minutes is an effective way to reduce exposure. It is recommended that you use a certified laboratory to perform the water test.
Fortunately, when household plumbing is the source of lead, the solution can be relatively simple. Follow-up testing of households with lead in drinking water generally confirms that flushing the water from plumbing lines can be an efficient method of minimizing exposure to lead from drinking water. As an added precaution, do not use the hot-water tap for cooking or drinking water (especially for making baby formula).
Although lead may be receiving increased attention, the information and recommendations associated with lead in drinking water are not new. To address this ongoing issue, the DNR regularly updates the informational brochure Lead in Drinking Waterwhich contains additional information that may be helpful. Local health departments are another source of information should people have additional questions regarding lead.
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