Copper
Cities measured
87
Detected in
87 / 87
EU limit
2000 μg/L
Highest
285 μg/L — Beirut
Overview
Copper is an essential trace element and natural antimicrobial. In drinking water it enters primarily from copper pipes — ubiquitous in Northern European building plumbing since the 1940s–70s. Stockholm's soft, low-alkalinity water is more corrosive to copper pipes than hard-water systems.
Health Relevance
Copper is essential for enzyme function and iron metabolism. Acute ingestion of > 3 mg/L causes nausea and vomiting. Chronic high-level exposure (> 1–2 mg/L over years) can cause liver damage — particularly in people with Wilson's disease.
Regulatory Limits
Drinking Water Directive 2020/2184
2 mg/L.
Controversy & Contested Science
Copper's antimicrobial properties are well-documented — hospital studies show copper-alloy surfaces reduce MRSA and Clostridioides difficile. Yet copper is simultaneously toxic at elevated concentrations in drinking water. After the Flint crisis highlighted lead pipe corrosion, attention shifted to copper: a 2021 study found copper levels at UK taps significantly higher in first-draw water than in utility monitoring samples — suggesting standard protocols underestimate exposure. Orthophosphate (used to inhibit lead leaching) can increase copper release under some conditions — an unintended interaction.