UK legal limit: 10 µg/L. Find out what lead is, its health effects, and how to check and reduce it in your tap water.
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Lead is a metal with no natural place in drinking water. Unlike almost every other parameter the water industry monitors, lead rarely originates at the treatment works or in the water main — it is picked up on the final leg of the journey, from older lead pipework and plumbing in or just outside a property. That is why lead is handled differently from other substances: the water leaving the treatment works can sit comfortably within standards while the reading at one particular kitchen tap is higher, depending entirely on that property's own pipes.
The UK legal limit (prescribed concentration value) for lead in drinking water is 10 µg/L — micrograms per litre — measured at the consumer's tap. Water companies manage lead at the network level chiefly through water chemistry, dosing orthophosphate to form a protective lining inside pipes that limits how much lead dissolves into the water. Across the 22 UK water companies and 1,614 supply zones we track, network water is managed to keep lead low; for an individual home, though, the single biggest factor is whether that property still has a lead supply pipe.
The main source is the lead communication and supply pipe — the run that connects the water main in the street to the property. Lead was the standard material for these connections in homes built before 1970. Lead solder used to join copper pipes was common until it was banned for drinking-water use in 1987, and some older brass fittings and taps contribute small amounts. The likelihood of lead therefore tracks closely with the age of the building: homes built before 1970 are the most likely to retain some original lead pipework, while properties built from the mid-1980s onward are very unlikely to.
Because lead depends on your specific plumbing rather than your water company, the most useful step is to estimate how likely it is that your property has a lead pipe. Our lead pipe risk model does exactly that — it scores lead-pipe likelihood at postcode level from property age and housing data across millions of UK homes, so you can see how likely a lead supply pipe is in your area before deciding whether to test or replace. Enter your postcode above to see your zone's reported lead figure, then open the lead risk checker for a property-age-based likelihood estimate.
Lead is a cumulative substance — it builds up in the body over time rather than being cleared quickly. The World Health Organization and the Drinking Water Inspectorate both take the view that lead intake should be kept as low as reasonably practicable, with the closest attention given to infants, young children and pregnant women, for whom lead exposure matters most. This is why the regulatory limit is set low and enforced at the tap, and why reducing any avoidable lead exposure is worthwhile even when a reading sits within the legal limit.
Several practical steps help. Run the tap for a minute or two first thing in the morning before using water for drinking or cooking — water that has stood in pipes overnight tends to give the highest reading, and flushing draws fresh water through from the main. Use only the cold tap for drinking and cooking, as hot water dissolves lead more readily. For treatment at the tap, reverse osmosis systems and carbon-block filters certified to NSF/ANSI 53 for lead reduction are effective; a standard jug filter is not certified for lead. The permanent fix is to replace any lead supply pipe — your water company is responsible for the section up to the property boundary and runs lead pipe replacement schemes in many areas. See our lead pipe risk guide and how to tell if your house has lead pipes for the practical next steps.
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Water leaving UK treatment works is managed to keep lead low, and companies dose orthophosphate to limit how much lead dissolves from pipes. Any lead measured at your tap almost always comes from an older lead supply pipe or plumbing in the property, not from the water supply itself. The legal limit is 10 µg/L at the tap.
Lead pipes are most likely in homes built before 1970. Our lead pipe risk model estimates the likelihood at postcode level from property age. You can also check the pipe where it enters your home: lead pipe is dull grey, soft enough to mark with a coin, and gives a dull note when tapped. A qualified plumber or your water company can confirm it.
10 µg/L (micrograms per litre), measured at the consumer's tap and set by the Drinking Water Inspectorate. It is enforced at the tap because lead is usually picked up from a property's own pipework rather than the water main.
Reverse osmosis systems and carbon-block filters certified to NSF/ANSI 53 for lead reduction remove lead effectively. Standard activated-carbon jug filters are not certified for lead. Look for the NSF/ANSI 53 lead claim on the product certificate.
Properties built before 1970 are most likely to retain an original lead supply pipe; lead solder was used to join copper pipes until it was banned for drinking water in 1987. Homes built from the late 1980s onward are very unlikely to have lead pipework. Check your postcode likelihood with our lead risk model.
Yes. Water that has stood in pipes overnight gives the highest reading. Running the cold tap for a minute or two draws fresh water through from the main and lowers the level. Always use the cold tap for drinking and cooking, as hot water dissolves lead more readily.