Copper
Also known as: Cu
A plumbing-corrosion contaminant regulated alongside lead — usually a sign of corrosive water chemistry.
Action level 1.3 mg/L. Regulated together with lead under the Lead and Copper Rule.
Short-term exposure to high copper causes gastrointestinal distress; long-term exposure can damage the liver and kidneys, and is dangerous for people with Wilson's disease.
Corrosion of copper household plumbing, especially in newer homes with copper pipes and acidic or poorly buffered water.
Corrosion-control treatment at the system level; at home, flush taps and the same point-of-use filters that address lead help.
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1
Copper enters drinking water the same way lead does: by corroding household plumbing. Acidic or poorly buffered water dissolves copper from pipes, particularly in newer homes.
Because it shares the Lead and Copper Rule, copper is managed through corrosion control — adjusting water chemistry so it stops dissolving metals out of the pipes.
States with the most copper violations
Community water systems with a related health-based violation since 2016.
| # | State | Systems |
|---|---|---|
| 1 | New York | 2 |
Common questions
What is the EPA limit for copper in drinking water?
Action level 1.3 mg/L. Regulated together with lead under the Lead and Copper Rule.
Is copper in drinking water dangerous?
Short-term exposure to high copper causes gastrointestinal distress; long-term exposure can damage the liver and kidneys, and is dangerous for people with Wilson's disease.
Where does copper in water come from?
Corrosion of copper household plumbing, especially in newer homes with copper pipes and acidic or poorly buffered water.
How do I remove copper from my water?
Corrosion-control treatment at the system level; at home, flush taps and the same point-of-use filters that address lead help.
Which states have the most copper violations?
Across U.S. community water systems, 2 have had a related health-based violation since 2016, led by New York with 2.