UK legal limit: 250 mg/L. What chloride is, its health context, and how to check and reduce it in your tap water.
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Chloride is a common, naturally occurring ion found in nearly all water. It comes from geology, road salt run-off and, in coastal areas, seawater influence. Chloride is an indicator parameter rather than a health-based one, with a UK standard of 250 mg/L set mainly for taste and corrosion reasons.
Chloride at the levels found in UK tap water is not a health concern. High chloride can make water taste salty and can be more corrosive to plumbing, which is why the 250 mg/L indicator value exists. It is not a toxicity limit.
If chloride affects the taste of your water, reverse osmosis certified to NSF/ANSI 58 reduces it effectively. Most UK households will not need to.
Chloride is one of the better-reported parameters in our dataset, with 517 supply zones reporting a figure. The highest zonal mean is around 136 mg/L — comfortably below the 250 mg/L indicator value — with most zones far lower. Coastal and salt-influenced areas tend to sit higher. Enter your postcode above to see your zone.
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No. Chloride is an indicator parameter set at 250 mg/L for taste and corrosion, not toxicity. At UK tap water levels it is not a health concern.
The UK indicator value for chloride is 250 mg/L. In our data the highest zonal mean is around 136 mg/L, well within that value.
A salty taste can come from higher chloride, more common in coastal or salt-influenced areas. It is an aesthetic issue rather than a safety one. Check your zone's figure by entering your postcode above.
Reverse osmosis certified to NSF/ANSI 58 reduces chloride effectively if taste is a concern. Standard carbon jug filters have limited effect on it.
No. Chlorine is the disinfectant added to keep water safe; chloride is a dissolved salt ion that occurs naturally. They are different things. See our separate chlorine guide.