Contaminant
Nickel
Chiefly a plumbing contaminant. Nickel leaches from chrome-plated taps and fittings, and concentrations are highest in the first water drawn after a period of standing.
Key facts
- Contaminant group
- Metal
- World Health Organization — guideline
- 70 µg/l
- European Union — legal limit
- 20 µg/l
- United Kingdom — legal limit
- 20 µg/l
Where it comes from
- Chrome-plated brass taps and fittings, the dominant source in drinking water
- Stainless steel in contact with acidic water
- Nickel plating, battery manufacture and metal finishing discharge
- Natural occurrence in ultramafic geology
How it behaves in water
Leaches from fittings into standing water, so first-draw concentrations can be several times higher than flushed ones. More soluble in soft, acidic water.
How it is measured
Micrograms per litre. As with lead, whether the tap was flushed before sampling substantially changes the result.
Regulatory position
| Jurisdiction | Value | Status | Notes |
|---|---|---|---|
| World Health Organization | 70 µg/l | guideline | — |
| European Union | 20 µg/l | legal limit | — |
| United Kingdom | 20 µg/l | legal limit | — |
Table sources
- World Health Organization — Guidelines for Drinking-water Quality. Public but restricted · CC BY-NC-SA 3.0 IGO
- European Commission — Drinking Water Directive (EU) 2020/2184 and reporting. Open — attribution required · European Commission reuse policy (Decision 2011/833/EU)
- Drinking Water Inspectorate — Drinking water quality in England and Wales. Open — attribution required · Open Government Licence v3.0
- United States Environmental Protection Agency — Safe Drinking Water Information System. Open · US Government work — public domain
Health context
Nickel is a common contact allergen, and a minority of nickel-sensitised people report symptoms from oral exposure. Systemic toxicity from drinking water at regulated concentrations is not established.
What removes it
| Row | Effective | Not reliably effective |
|---|---|---|
| 1 | Flushing the tap before drawing water for drinking | Boiling, which concentrates it |
| 2 | Replacing high-leaching fittings | Activated carbon alone |
| 3 | Reverse osmosis | — |
| 4 | Ion exchange | — |
Relationships
Related intelligence
Sources
- World Health Organization — Guidelines for Drinking-water Quality. Public but restricted · CC BY-NC-SA 3.0 IGO
- Peer-reviewed scientific literature — Open-access hydrology, water chemistry and water use research. Public but restricted · Publisher terms — public access, reuse not clearly granted