Zinc
Cities measured
87
Detected in
87 / 87
Highest
18.5 μg/L — Karachi
Overview
Zinc enters water from corrosion of galvanised steel pipes — widely installed in European buildings from the 1920s–60s. Zinc is an essential trace element required for 300+ enzymatic reactions and immune function.
Health Relevance
Zinc deficiency affects an estimated 2 billion people globally. At drinking water concentrations, zinc is not a health concern. Acute high doses (> 4 mg/L) cause nausea. Long-term very high zinc inhibits copper absorption.
Regulatory Limits
Drinking Water Directive 2020/2184
No EU regulatory limit. WHO guideline: 3 mg/L (taste threshold).
Controversy & Contested Science
Historic zinc coatings on galvanised pipes contained cadmium and lead as impurities. Galvanised building plumbing may thus release zinc, lead, and cadmium simultaneously in first-draw water. Regulatory attention has focused almost entirely on lead service lines (street to building) while internal building plumbing remains largely unregulated and unmonitored. An estimated 30–40% of older apartment buildings in Stockholm's inner city have at least partial galvanised internal plumbing.