Tap water in KT20, Reigate and BansteadSafe to drink.Very 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.
8.6 / 10
The tank is as full as the score. The specks are the minerals that make water hard.
What to do about it
Hard water: compare softener quotes
At 225 mg/L a softener is the only thing that stops limescale. Filters do not soften water.
It pays for itself in most homes at this hardness, through a boiler that stays efficient and appliances that last.
Waterdrop G3P600 Reverse Osmosis
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Waterdrop 10UA Under Sink
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High-volume under-sink filtration without RO complexity
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What's in a glass of KT20 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 98% of it. 17 of 19 substances used under a quarter of theirs.
- Nitrite98%
- Nitrate49%
- Lead23%
- Trihalomethanes20%
- Copper12%
- Bromate10%
- Fluoride9%
- Colour9%
- Cadmium8%
- Mercury7%
- Arsenic7%
- Antimony6%
- Nickel5%
- Chromium5%
- Aluminium4%
- Boron4%
- Iron4%
- Selenium3%
- Manganese2%
- Coliform Bacteria none found
- E. coli none found
- Conductivity 514 µS/cm
All 23 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Nitrite | 0.49 mg/L | 0.5 mg/L | 98% |
| 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 | 514 µS/cm | No legal limit | – |
| Fluoride | 0.14 mg/L | 1.5 mg/L | 9% |
| Nitrate | 24.7 mg/L | 50 mg/L | 49% |
| Hardness (as CaCO3) | 225 mg/L | No legal limit | – |
| Aluminium | 0.0083 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 | 0.04 mg/L | 1 mg/L | 4% |
| Cadmium | 0.0004 mg/L | 0.005 mg/L | 8% |
| Chromium | 0.0025 mg/L | 0.05 mg/L | 5% |
| Copper | 0.23 mg/L | 2 mg/L | 12% |
| Iron | 0.008 mg/L | 0.2 mg/L | 4% |
| Lead | 0.0023 mg/L | 0.01 mg/L | 23% |
| Manganese | 0.0012 mg/L | 0.05 mg/L | 2% |
| Mercury | 0.00007 mg/L | 0.001 mg/L | 7% |
| Nickel | 0.001 mg/L | 0.02 mg/L | 5% |
| Selenium | 0.001 mg/L | 0.04 mg/L | 3% |
| Trihalomethanes | 0.02 mg/L | 0.1 mg/L | 20% |
| Bromate | 0.001 mg/L | 0.01 mg/L | 10% |
225mg of limescale minerals in every litre
This is the water that furs up kettles
Very hard on the UK scale. It is fine to drink. It is hard on boilers, showers, skin and anything that heats water, and a jug or tap filter will not change that.
Softener quotes for KT20
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Your river is the Wandle (Croydon to Wandsworth) and the Graveney, rated moderate
The Environment Agency rated the Wandle (Croydon to Wandsworth) and the Graveney 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 fish. 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
KT20 in short
Tap water in KT20 (Reigate and Banstead) is supplied by Thames Water in the Reigate and Banstead Central zone and scores 8.6 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 98% 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
- 4th cleanest of 5 areas tested in Reigate and Banstead1 area in Reigate and Banstead scored lower. The best is RH6 on 9.3.
- Hard water at 225 mg/LHard starts at 180 mg/L, the point where a softener begins to pay for itself. Limescale will build up in KT20. How hardness is measured
Questions about KT20 water
Is KT20 tap water safe to drink?
Based on the latest tests, KT20 (Reigate and Banstead) water scores 8.6/10, which is safe. 1 of 23 tested contaminants exceeded recommended levels. Water is supplied by Thames Water.
What contaminants are in KT20 water?
We tested 23 contaminants in KT20 water. 1 were flagged, including Nitrite.
Who supplies water in KT20?
KT20 (Reigate and Banstead) is supplied by Thames Water. You can view their full profile and compliance data on our supplier page.
Is KT20 water hard or soft?
Water in KT20 (Reigate and Banstead) has a hardness of 225 mg/L CaCO3, which is classified as hard. Hard water can cause limescale buildup. A water softener or filter jug may help.
Should I use a water filter in KT20?
With 1 contaminant above recommended levels in KT20, 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 KT20 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for KT20, 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 KT20?
The Environment Agency rated the Wandle (Croydon to Wandsworth) and the Graveney 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 fish. 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 KT20, which is treated before it reaches homes.
Keep reading
- Best Water Softener UKHarvey, Kinetico, BWT, Monarch and Water2Buy compared, with real costs
- Do I Need a Water Softener?The hardness bands, the symptoms, and a postcode check
- UK Water Hardness MapIs your water hard or soft, and does it matter?
- Best Water Filters UKEvery filter type compared on what it actually removes
- Do I need a water softener?The hardness bands, the symptoms, and when the answer is no
- Best water softener UKHarvey, Kinetico, BWT, Monarch and Water2Buy compared
- Water softener costUnit, fitting and salt, and how long the payback takes
- Installation explainedWhere it goes, the bypass tap, the drain, DIY or plumber
- Harvey vs KineticoThe two premium twin-cylinder brands, side by side
- Softener salt guideTablet, block or granular, and how much you get through
- Salt-free softenersConditioners and electronic descalers, honestly assessed
Nitrate levelsHow to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map
River and groundwater readings near KT20
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 |
|---|---|---|
| Turbidity | 4.7 NTU | 4 NTU |
| pH | 7.78 pH | None |
| Temperature | 18.9 °C | None |
| Conductivity | 876 µS/cm | None |
| Nitrate | 13 mg/L | 50 mg/L |
| Nitrite | 0.029 mg/L | 0.5 mg/L |
| Phosphate | 4.4 mg/L | None |
| Dissolved Oxygen | 7.52 mg/L | None |
| Ammonia | 0.059 mg/L | 0.5 mg/L |
| Lead | 0.00014 mg/L | 0.01 mg/L |
| Cadmium | 0.000014 mg/L | 0.005 mg/L |
| Hardness (as CaCO3) | 245 mg/L | None |
| Fluoride | 0.14 mg/L | 1.5 mg/L |
| Zinc | 0.022 mg/L | None |
| Nickel | 0.0011 mg/L | 0.02 mg/L |
| Manganese | 0.0011 mg/L | 0.05 mg/L |
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