Lead in Well Water: Testing Your Pipes, Pump and Fixtures

On this page

1. Where lead in well water comes from
2. Corrosive water drives it
3. Reference levels
4. When to test for lead
5. How to sample
6. Reducing exposure
7. Sources

Where lead in well water comes from

For most wells, the source isn’t the groundwater. It’s the plumbing. Penn State Extension lists:

• Lead pipes and leaded solder
• Brass faucets and fixtures, including chrome-plated brass, which can leach lead even in homes with plastic pipes
• Brass fittings on certain submersible well pumps

Penn State notes that copper plumbing installed before January 1991 likely used lead solder, and homes with fixtures installed after 2014 have a lower risk.

Corrosive water drives it

Acidic water (pH below 7) that’s low in calcium carbonate tends to be more corrosive and dissolves more lead. Soft water and warm water also tend to be more corrosive (Penn State). CDC makes the same point: pH that’s too low or high can damage pipes and let metals like lead leach into water. That’s one reason pH is part of the annual baseline test.

In a 2006–2007 survey of Pennsylvania private water supplies, 12% had lead above 15 µg/L. The researchers found that high levels could “nearly always” be traced to corrosion of plumbing components (Penn State).

Reference levels

• Health goal: zero. EPA treats lead as having no safe level (EPA).
• Action level: 0.015 mg/L (15 µg/L) under the current rule for public water systems. EPA’s 2024 Lead and Copper Rule Improvements lower that to 0.010 mg/L (10 µg/L) for public systems starting November 1, 2027 (Federal Register, EPA FAQ).

An action level is the point where a utility must take corrective steps. It is not a “safe” line for your household.

When to test for lead

EPA recommends testing for pH, lead and copper if your plumbing or service lines may contain lead, or if you see signs of corrosion (EPA). Signs include blue-green stains, pinhole leaks, and treatment equipment that wears out quickly.

How to sample

Penn State describes two sample types:

• First-draw: cold water that sat in the pipes overnight, collected first thing in the morning. It shows how much lead builds up while water sits in your plumbing.
• Running (flushed): collected after the water has run. It helps show whether lead is coming from fixtures and pipes or from elsewhere in the system.

Follow your lab’s instructions; some ask for both. Find a certified lab through EPA’s directory, or use a mail-in metals test that uses a state-certified laboratory (for example, Tap Score: Essential well water test →—confirm certification with your state).

Reducing exposure

From Penn State Extension:

1. Use a filter certified to reduce lead for all drinking and cooking water. Penn State calls this “the most reliable way to prevent exposure.” Look for NSF/ANSI 53 (filters) or NSF/ANSI 58 (RO) with a lead reduction claim on the package, and confirm it in NSF’s listings.
2. Flush before use. Running the cold tap (or briefly running the dishwasher or a load of laundry to flush the plumbing) can lower lead levels after water has sat in the pipes, but Penn State notes that flushing alone isn’t reliable.
3. Replace leaded components. This is the permanent fix. Use pipe marked NSF-61 or NSF-pw for replacements.
4. Have the pump checked. If metal parts on a submersible pump are corroding, they could be adding lead.
5. Address corrosive water with a water treatment professional, guided by your pH and other test results.

Certified-filter options. Check each model’s NSF lead claim before buying: Aquasana: under-sink filters → · iSpring: RO systems → · Shop NSF 53 lead filter pitcher on Amazon →

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