EPA legal limit
1.3 ppm
Maximum Contaminant Level
EWG health guideline
No guideline
Science-based, stricter target
Health effects
Short-term exposure above 1.3 ppm can cause nausea, vomiting, and diarrhea. Long-term high-level exposure may cause liver and kidney damage. Children are more sensitive to copper toxicity than adults.
Where it comes from
Leaching from copper pipes and copper-containing fittings, particularly in newer homes where copper pipes have not yet developed a protective mineral coating. Soft, acidic water accelerates copper leaching.
How it's regulated
Regulated alongside lead under the Lead and Copper Rule. Action level is 1.3 ppm at the 90th percentile of tap samples. Utilities must take action if >10% of samples exceed this level.
How to filter copper
Not all filters address copper. Look for independently certified filters — NSF International certification means the removal claim has been independently verified.
Frequently asked questions
What is copper?
A naturally occurring metal that leaches into drinking water primarily from copper household plumbing. At low levels it is an essential nutrient; at high levels it causes gastrointestinal effects.
What are the health effects of copper?
Short-term exposure above 1.3 ppm can cause nausea, vomiting, and diarrhea. Long-term high-level exposure may cause liver and kidney damage. Children are more sensitive to copper toxicity than adults.
Is copper regulated in drinking water?
Regulated alongside lead under the Lead and Copper Rule. Action level is 1.3 ppm at the 90th percentile of tap samples. Utilities must take action if >10% of samples exceed this level.
Where does copper come from?
Leaching from copper pipes and copper-containing fittings, particularly in newer homes where copper pipes have not yet developed a protective mineral coating. Soft, acidic water accelerates copper leaching.
How do I remove copper from tap water?
The most effective methods for removing copper are: Reverse osmosis (RO), NSF 58 certified RO system. Look for NSF-certified systems — independent certification confirms removal claims have been verified.
Is copper in your water?
Enter your ZIP code to see the measured level in your specific utility.