Nickel
Cities measured
87
Detected in
87 / 87
EU limit
20 μg/L
Highest
12.4 μg/L — Karachi
Overview
Nickel enters drinking water primarily from metal taps and fittings, particularly in first-draw water after prolonged stagnation. Utility monitoring typically measures 'running water' — so tap-fitting contamination is largely invisible to official reporting.
Health Relevance
Nickel is a probable human carcinogen (IARC Group 2B) via ingestion and a Group 1 carcinogen via inhalation. It is also the most common cause of contact dermatitis in Europe. Chronic gastrointestinal effects occur at higher concentrations.
Regulatory Limits
Drinking Water Directive 2020/2184
20 μg/L.
Controversy & Contested Science
A 2019 study of 1,000+ UK homes found first-flush nickel concentrations exceeding EU limits in 15% of homes — almost all from tap and fitting corrosion, not utility supply. Utilities monitor only network water (running samples), so tap-fitting contamination is invisible to official statistics. Consumer advocacy groups have called for monitoring protocols capturing first-draw tap water (after standing), which better represents actual human exposure. EU tap-fitting regulations (EN 15664-1) set nickel release standards for new fittings, but millions of older fittings remain installed with no replacement timeline.