Lead in well water

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What you need to know about lead

These counties see the most lead in their wells

Ranked by the share of tested wells with a result over the limit. We only list counties with at least 25 tested wells, so a few bad results can't skew the ranking.

See the full rankings and download the data

Lead gets into well water from your plumbing

Lead is rarely in the groundwater itself. In a national USGS study, fewer than 1% of wells in drinking-water aquifers had lead over 15 µg/L. The lead people find at the tap comes from the well system and the house.

Penn State Extension lists the usual sources: lead solder on copper pipes, brass faucets and fittings (including chrome-plated brass), and brass fittings on some submersible well pumps made through the mid-1990s. Brass fixtures can leach lead even in a house with plastic pipes.

The water's chemistry decides how much dissolves. Acidic water (pH below 7) and soft water are more corrosive, and warm water more than cold. Lead is highest in the first water out of the tap after it sits in the pipes.

Older homes carry more risk. The EPA says lead pipes are more likely in homes built before 1986. In 1986 "lead-free" meant under 8% lead in pipes and fixtures and 0.2% in solder. Since 2014 it has meant 0.25% on surfaces that touch drinking water.

It's common in some places. A Penn State survey of private wells in Pennsylvania found 12% over 15 µg/L, almost always from plumbing corrosion.

Children and pregnant women face the most risk

The EPA and CDC agree there's no known safe level of lead in a child's blood. The EPA says even low levels in children can cause behavior and learning problems, lower IQ and hyperactivity, slowed growth, hearing problems and anemia.

In pregnancy, lead stored in the mother's bones can be released and reach the baby. The EPA lists reduced growth of the fetus and premature birth among the effects. Adults can develop kidney problems and high blood pressure.

The EPA estimates drinking water can be 20% or more of a person's lead exposure. For babies on mostly formula mixed with tap water, it can be 40% to 60%.

The EPA says bathing and showering are fine, even above the action level, because skin doesn't absorb lead from water.

Take a first-draw sample from the kitchen tap

Lead has no taste, smell or color. Penn State recommends 2 samples from the kitchen tap:

• First draw: cold water that sat in the pipes overnight, collected first thing in the morning.
• Running: cold water after it runs for at least 1 minute.

Comparing them shows where the lead comes from. If lead stays above 15 µg/L after 1 to 2 minutes of running, Penn State says it's probably in the water before it enters the household plumbing, such as from the pump or well fittings.

Ask for "total lead," which counts tiny particles that break loose from pipes. Penn State puts the cost at $15 to $100.

Some states test well water for free or at low cost. Check yours before you pay.

Use a certified filter for drinking water, and fix corrosive water

Start with habits the EPA recommends. Use only cold water for drinking, cooking and baby formula. Run the tap or do a load of laundry or dishes before drinking water that sat for hours. Penn State notes that flushing alone isn't a reliable fix.

Costs are from Penn State Extension.

Skip the water softener for lead. Penn State says softeners remove lead poorly, and softened water is usually more corrosive.

Questions people ask about lead