Tap water in KT17, Epsom and EwellSafe to drink.Slightly hard.
Supplied by Thames Water. 74 samples, 23 substances, latest on 31 December 2025. Everything is inside the legal limit. One result, nitrite, sits close to the line.
8.8 / 10
The tank is as full as the score. The specks are the minerals that make water hard.
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What's in a glass of KT17 water
Every bubble is a substance the lab measured. The higher it floats, the closer it came to its legal limit, the dashed line at the top.
Nitrite came closest to a limit, at 76% of it. 16 of 19 substances used under a quarter of theirs.
- Nitrite76%
- Trihalomethanes40%
- Nitrate38%
- Lead12%
- Nickel11%
- Bromate10%
- Colour9%
- Fluoride9%
- Cadmium8%
- Mercury7%
- Arsenic7%
- Antimony6%
- Chromium5%
- Iron5%
- Aluminium4%
- Boron3%
- Copper2%
- Manganese1%
- Selenium1%
- Coliform Bacteria none found
- E. coli none found
- Conductivity 363 µS/cm
All 23 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Nitrite | 0.38 mg/L | 0.5 mg/L | 76% |
| Coliform Bacteria | 0 count/100ml | Must be zero | None found |
| E. coli | 0 count/100ml | Must be zero | None found |
| Colour | 1.8 mg/L Pt/Co | 20 mg/L Pt/Co | 9% |
| Conductivity | 363 µS/cm | No legal limit | – |
| Fluoride | 0.13 mg/L | 1.5 mg/L | 9% |
| Nitrate | 18.9 mg/L | 50 mg/L | 38% |
| Hardness (as CaCO3) | 138 mg/L | No legal limit | – |
| Aluminium | 0.0082 mg/L | 0.2 mg/L | 4% |
| Antimony | 0.0003 mg/L | 0.005 mg/L | 6% |
| Arsenic | 0.0007 mg/L | 0.01 mg/L | 7% |
| Boron | 0.03 mg/L | 1 mg/L | 3% |
| Cadmium | 0.0004 mg/L | 0.005 mg/L | 8% |
| Chromium | 0.0025 mg/L | 0.05 mg/L | 5% |
| Copper | 0.03 mg/L | 2 mg/L | 2% |
| Iron | 0.01 mg/L | 0.2 mg/L | 5% |
| Lead | 0.0012 mg/L | 0.01 mg/L | 12% |
| Manganese | 0.0007 mg/L | 0.05 mg/L | 1% |
| Mercury | 0.00007 mg/L | 0.001 mg/L | 7% |
| Nickel | 0.0022 mg/L | 0.02 mg/L | 11% |
| Selenium | 0.0004 mg/L | 0.04 mg/L | 1% |
| Trihalomethanes | 0.04 mg/L | 0.1 mg/L | 40% |
| Bromate | 0.001 mg/L | 0.01 mg/L | 10% |
138mg of limescale minerals in every litre
Middling hardness. Some scale, slowly
Below the point where a softener pays for itself. Descaling the kettle now and then is all most homes need.
Your river is the Hogsmill, rated moderate
The Environment Agency rated the Hogsmill as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by phosphate and insects and other small river life. It fails the chemical test, as every river, estuary and stretch of coast in England does, because of long-lasting pollutants such as mercury, PFOS (a forever chemical) and old flame retardants.
None of this is a test of your tap water. Environment Agency record · River health across England
KT17 in short
Tap water in KT17 (Epsom and Ewell) is supplied by Thames Water in the Epsom and Ewell Central zone and scores 8.8 out of 10, against an England and Wales average of 9.0. 1 of 23 tested substances was close to or over a limit. The latest sample is from 31 December 2025.
- Nitrite is within its legal limit but flagged, at 76% of the 0.5 mg/L maximumAnything over three quarters of a limit is flagged here as worth watching. It has not gone over. See every reading
- The lowest score of the 3 areas tested in Epsom and EwellKT17 scores 8.8 out of 10. The best in Epsom and Ewell, KT19, scores 9.3.
- Moderately hard water at 138 mg/LSome scale over time in KT17, but not enough to justify a softener for most homes. How hardness is measured
Questions about KT17 water
Is KT17 tap water safe to drink?
Based on the latest tests, KT17 (Epsom and Ewell) water scores 8.8/10, which is safe. 1 of 23 tested contaminants exceeded recommended levels. Water is supplied by Thames Water.
What contaminants are in KT17 water?
We tested 23 contaminants in KT17 water. 1 were flagged, including Nitrite.
Who supplies water in KT17?
KT17 (Epsom and Ewell) is supplied by Thames Water. You can view their full profile and compliance data on our supplier page.
Is KT17 water hard or soft?
Water in KT17 (Epsom and Ewell) has a hardness of 138 mg/L CaCO3, which is classified as moderately hard. This is a moderate hardness level.
Should I use a water filter in KT17?
With 1 contaminant above recommended levels in KT17, a water filter could help. A filter jug or under-sink filter can reduce most common contaminants. See our filter recommendations for your area.
Are there PFAS forever chemicals in KT17 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for KT17, and the Environment Agency has no PFAS detections in rivers or groundwater within 10 km of it. That reflects where sampling has happened as much as the water itself.
How clean is the river near KT17?
The Environment Agency rated the Hogsmill as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by phosphate and insects and other small river life. It fails the chemical test, as every river, estuary and stretch of coast in England does, because of long-lasting pollutants such as mercury, PFOS (a forever chemical) and old flame retardants. This is a rating of the river, not of tap water in KT17, which is treated before it reaches homes.
Keep reading
- Best Water Filters UKEvery filter type compared on what it actually removes
- Is UK Tap Water Safe?Everything you need to know about tap water safety in the UK
- How to Test Your Tap WaterFrom DIY strips to professional lab analysis
- Best Water Filter Jug UKBRITA vs ZeroWater vs the rest, tested against real data
Nitrate levelsHow to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map
River and groundwater readings near KT17
Environment Agency samples from rivers, groundwater and reservoirs nearby. Not your tap water. For scale they are shown against drinking water limits; rivers are judged against much stricter environmental standards, and on those every river in England fails for chemicals.
| Substance | Reading | Drinking water limit |
|---|---|---|
| pH | 7.3 pH | None |
| Temperature | 10.8 °C | None |
| Conductivity | 1486 µS/cm | None |
| Phosphate | 0.074 mg/L | None |
| Dissolved Oxygen | 8.42 mg/L | None |
| Ammonia | 0.08 mg/L | 0.5 mg/L |
| Nitrate | 6.1 mg/L | 50 mg/L |
| Nitrite | 0.11 mg/L | 0.5 mg/L |
| Lead | 0.00031 mg/L | 0.01 mg/L |
| Nickel | 0.0023 mg/L | 0.02 mg/L |
| Cadmium | 0.000012 mg/L | 0.005 mg/L |
| Hardness (as CaCO3) | 503 mg/L | None |
| Zinc | 0.018 mg/L | None |
| Copper | 0.00006 mg/L | 2 mg/L |
Get alerts for your area
We'll email you when water quality data changes for KT17.