A free report for your postcode, built from real drinking-water tests.
2,245 postcode districts with tap-water tests, 29 contaminants checked against legal limits, September 2026 most recent test in the data. Right now the gap runs from DA9 (Dartford) at 7.0/10 to NE47 (Northumberland) at 9.8/10. Your report shows where your postcode sits, and which readings put it there.
Every tank is a real district, filled to its score out of 10. Tap one to see what is in the water.
The lowest scores in recent tap-water tests. A low score is a reason to look closer, not a sign the water is unsafe.
The highest scores in the country right now.
Hard water is safe to drink and rough on kettles, boilers and showers. Each dot is a postcode district, coloured by how much limescale mineral is in the water.
Solid dots are districts with their own hardness reading. Faint dots take the median of their postcode area. Grey land has no hardness in the open data we use yet. Hover a dot for the value, click it for the full report.
Water hardness checkerThe full hardness mapDo I need a water softener?
Of everything we link to, these three are what readers click most: a jug for drinking water, a shower filter for chlorine, and a reverse osmosis unit that needs no plumbing. They are starting points, not a prescription. Check your postcode above and the report tells you what your own water needs.
The jug for cleaner drinking water
ZeroWater 12-Cup Ready-Pour
Jug Filter · NSF/ANSI 53, NSF/ANSI 401
Typical price
£40approx.
Affiliate link: we may earn a commission at no extra cost to you.
For dry skin and hair after a shower
Jolie Filtered Showerhead
Shower Filter
Typical price
£85approx.
Affiliate link: we may earn a commission at no extra cost to you.
Reverse osmosis without a plumber
Osmio Zero 2.0 Countertop RO
Reverse Osmosis
Typical price
£495approx.
Affiliate link: we may earn a commission at no extra cost to you.
Affiliate link: we may earn a commission at no extra cost to you. How recommendations are funded
LondonManchesterBirminghamLeedsGlasgowEdinburgh
LondonSouth East EnglandSouth West EnglandEast of EnglandWest MidlandsEast MidlandsYorkshire and the HumberNorth West EnglandNorth East EnglandWalesScotland
Thames WaterSevern TrentUnited UtilitiesYorkshire WaterAnglian WaterSouthern WaterAll water companies
WF10 WakefieldS63 BarnsleyWF12 KirkleesS9 SheffieldHX2 CalderdaleS73 BarnsleyHU6 Kingston upon Hull, City ofHX6 CalderdaleYO24 YorkS36 BarnsleyWF14 KirkleesLS9 LeedsDL9 North YorkshireDL10 North YorkshireBD3 BradfordS13 SheffieldHD5 KirkleesLS7 LeedsS35 SheffieldYO15 East Riding of YorkshireWF2 WakefieldHU17 East Riding of YorkshireHD7 KirkleesHD9 Kirklees
Type your postcode above to find out. Your free report scores your area out of 10 using the latest tests from your water company and the Environment Agency, lists every substance checked and shows which ones came close to, or over, the legal limit. Reports are available for 2,245 postcode districts across the UK.
Almost always, yes. UK tap water is among the most tested in the world and nearly every sample passes the legal limits. A low score on this site does not mean the water is unsafe. It means some readings sat closer to the limit than in other areas. Your report names those readings, so you can decide whether a filter is worth having.
Enter the first part of your postcode, such as SW1A or M1, in the search box. You get a report straight away: a score out of 10, the water company that supplies you, how hard your water is, and results for 29 contaminants including lead, PFAS and nitrate. It is free and there is no sign-up.
Mostly water. The rest is small amounts of minerals such as calcium and magnesium, which make water hard or soft, a trace of chlorine that keeps it clean on the way to your tap, and very low levels of substances picked up from pipes and the environment, such as lead, nitrate or PFAS. Each has a legal limit set well below the level thought to affect health, and your postcode report shows how your area's readings compare.
Data from UK water companies, the Environment Agency and the Drinking Water Inspectorate. About TapWater.uk · How we score · Where the data comes from