Lead in well water: what your result means
Lead in well water almost always comes from plumbing, not the aquifer. There is no known safe level. If any is detected, run the tap before drinking, use cold water for cooking, and look for the source.
- US (EPA)
- Action level 0.015 mg/L (15 ppb), lowering to 0.010 mg/L on November 1, 2027. The health goal is zero.
- Ontario
- 0.010 mg/L. Health Canada's guideline is 0.005 mg/L, as low as reasonably achievable.
What it is
Lead dissolves from old pipes, lead solder and brass fittings, more when water is acidic (low pH) or has been sitting in the pipes. Children and pregnant people are most at risk.
What your number means
- Within limitsNot detected
No lead found in this sample.
- Worth a lookAny amount detected
Lower it with flushing and cold water, and find the source in your plumbing.
- Act nowAbove the limit
Use another source or a certified filter for drinking and cooking, and plan to replace the source.
What to do
- Run the cold tap for a minute or two before drinking if water has been sitting for hours.
- Use only cold water for drinking, cooking and formula.
- Use a filter certified to reduce lead for drinking water.
- Check your pH. Acidic water pulls lead from plumbing; a neutralizing filter can help.
- Look for the source: lead service pipe, old solder or brass parts.
How often to test
Every few years, and after plumbing work or if your pH is low.
Common questions
How can my well have lead if the aquifer doesn't?
The lead is usually picked up inside your own plumbing, between the well and the tap.
Does boiling remove lead?
No. Boiling can concentrate it.
Should my kids be tested?
If lead was found, ask your doctor about a blood lead test, especially for young children.
Sources: EPA drinking water standards; Ontario Drinking Water Quality Standards, O. Reg. 169/03; Health Canada drinking water guidelines. Limits checked October 2026.