UK legal limit: 1 µg/L. What mercury is, its health context, and how to check and reduce it in your tap water.
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Mercury is a heavy metal that can enter the environment from industrial activity and natural sources. It is one of the most tightly regulated substances in drinking water, with a UK legal limit (PCV) of just 1 µg/L — among the strictest of any parameter.
Mercury, particularly as methylmercury, is a neurotoxin, and human exposure is dominated by certain types of fish rather than drinking water. In UK tap water, mercury is typically at or near the detection limit — far below the 1 µg/L standard.
Reverse osmosis certified to NSF/ANSI 58 and some certified carbon-block filters reduce mercury. At UK tap water concentrations, treatment is rarely necessary.
Mercury is reported by 90 supply zones in our dataset. The highest recorded mean is 0.05 µg/L — one-twentieth of the already strict 1 µg/L limit — with most zones at or near the detection floor. Enter your postcode above to see your zone.
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Mercury in UK tap water is typically at or near the detection limit. In our data, 90 zones report it with a highest mean of 0.05 µg/L, far below the 1 µg/L legal limit.
The UK Prescribed Concentration Value for mercury is 1 µg/L — one of the strictest drinking-water standards.
Mercury is a neurotoxin, but human exposure comes mainly from certain fish, not tap water. UK tap water sits far below the strict 1 µg/L limit.
Reverse osmosis certified to NSF/ANSI 58 and some certified carbon-block filters reduce mercury. At UK tap water levels this is rarely needed.
For mains supplies this is not usually necessary — water companies test routinely and levels are very low. Enter your postcode above to see whether your zone reports mercury.