The best and worst tap water in the UK in 2026

On the most recent tests, the highest-scoring areas are NE48 (Northumberland) at 9.8/10, NE47 (Northumberland) at 9.8/10 and NE41 (Northumberland) at 9.8/10. Nothing in NE48's water came close to a legal limit. Rankings move as new test results come in.

Northumberland currently has the top-scoring district, NE48 (Northumberland), at 9.8/10, supplied by Northumbrian Water. Water quality varies street by street rather than city by city, so two postcodes in the same city can sit at opposite ends of this list. Check your own postcode for the reading that applies to your tap. Across whole companies, Northumbrian Water has the highest average at 9.5/10.

Yes. UK tap water is among the most tested in the world and almost every sample passes the legal limits. A low score here does not mean the water is unsafe. Even DA9 (Dartford), the lowest-scoring area at 7.0/10, is supplied as drinking water that meets the rules. A low score means some readings sat closer to their limits than elsewhere, which is worth knowing if you are pregnant, have a baby or are sensitive to taste.

Because the water starts in different places. Areas fed by upland reservoirs tend to have soft water with few dissolved minerals. Areas drawing on chalk or sandstone aquifers have hard water and, where farmland sits above, more nitrate. Older pipes can add lead, and the disinfection needed to keep water clean leaves traces of chlorine and its by-products. The lowest-scoring areas right now are DA9 (Dartford) at 7.0/10, E2 (Tower Hamlets) at 7.0/10 and IG4 (Redbridge) at 7.0/10.

Every area gets a score out of 10. For each of the 28 substances tested, we measure how close the reading came to its legal limit: a reading at a tenth of the limit scores 9, a reading at the limit scores 0. Substances that matter most for health, such as lead, PFAS and bacteria, count three times as much as ones that mostly affect taste, such as chlorine or hardness. Drinking-water tests make up 80% of the final score and Environment Agency river and groundwater monitoring the other 20%. The full method is on our methodology page. Read the methodology