Where copper comes from
- corrosion of copper pipes and plumbing fixtures accelerated by acidic or low-alkalinity water
- naturally acidic (low pH) private well water attacking copper household plumbing
- soft (low mineral) water with low buffering capacity
- mining drainage and industrial discharge (less common in private wells)
Health considerations
- acute gastrointestinal distress — Nausea, vomiting, and diarrhea at concentrations above the action level (1,300 μg/L). EPA MCL-equivalent Action Level set at 1,300 μg/L under the Lead and Copper Rule.
- liver and kidney damage (chronic exposure) — Wilson’s disease patients and infants with genetic cholestatic liver disease are at higher risk from chronic elevated copper intake. Healthy adults tolerate typical tap water concentrations well below the action level.
EPA Action Level of 1,300 μg/L (1.3 mg/L) under the Lead and Copper Rule — not a traditional MCL. The action level triggers corrosion control requirements for public systems when >10% of first-draw samples exceed it. MCLG = 1,300 μg/L. For private wells with acidic water, corrosion control (pH adjustment) is more effective than filtration.
Who is most at risk
- infants (copper formula water concern if pH < 6.5)
- people with Wilson’s disease or Indian childhood cirrhosis
- households with new copper plumbing (most leaching in first 5 years)
- well owners with acidic water (pH < 7.0)
Testing
ICP-MS (EPA Method 200.8) or ICP-OES (EPA 200.7); first-draw sample from tap after 6+ hours of standing required to capture plumbing leaching; not typically an aquifer-source analyte in WQP groundwater data
Find a certified lab and learn how to collect a sample
Treatment
- pH correction (calcite upflow neutralizer, soda ash injection) — raises pH above 7.0 to reduce corrosivity
- reverse osmosis (point-of-use, removes copper at tap)
- activated carbon block filter (certified NSF/ANSI 53 for copper reduction)
- orthophosphate corrosion inhibitor (municipal scale — coats pipes)