Tap water in OX12, Vale of White HorseSafe to drink.Very hard.
Supplied by Thames Water. 76 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 258 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
£70typical price
High-volume under-sink filtration without RO complexity
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What's in a glass of OX12 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 86% of it. 16 of 19 substances used under a quarter of theirs.
- Nitrite86%
- Nitrate43%
- Nickel30%
- Trihalomethanes15%
- Lead13%
- Bromate10%
- Colour9%
- Fluoride8%
- Cadmium8%
- Mercury7%
- Arsenic7%
- Aluminium6%
- Antimony6%
- Chromium5%
- Iron5%
- Boron4%
- Manganese1%
- Copper1%
- Selenium1%
- Coliform Bacteria none found
- E. coli none found
- Conductivity 545 µS/cm
All 23 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Nitrite | 0.43 mg/L | 0.5 mg/L | 86% |
| 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 | 545 µS/cm | No legal limit | – |
| Fluoride | 0.12 mg/L | 1.5 mg/L | 8% |
| Nitrate | 21.4 mg/L | 50 mg/L | 43% |
| Hardness (as CaCO3) | 258 mg/L | No legal limit | – |
| Aluminium | 0.0127 mg/L | 0.2 mg/L | 6% |
| 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 | 0.02 mg/L | 2 mg/L | 1% |
| Iron | 0.01 mg/L | 0.2 mg/L | 5% |
| Lead | 0.0013 mg/L | 0.01 mg/L | 13% |
| Manganese | 0.0006 mg/L | 0.05 mg/L | 1% |
| Mercury | 0.00007 mg/L | 0.001 mg/L | 7% |
| Nickel | 0.006 mg/L | 0.02 mg/L | 30% |
| Selenium | 0.0004 mg/L | 0.04 mg/L | 1% |
| Trihalomethanes | 0.015 mg/L | 0.1 mg/L | 15% |
| Bromate | 0.001 mg/L | 0.01 mg/L | 10% |
258mg 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 OX12
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Your river is the Letcombe Brook, rated poor
The Environment Agency rated the Letcombe Brook as poor for ecological health in its 2025 assessment, meaning the river is badly affected, with much of the expected wildlife missing. It is held back by fish and water plants and algae. 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
OX12 in short
Tap water in OX12 (Vale of White Horse) is supplied by Thames Water in the Vale of White Horse 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 86% 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 cleanest tap water of the 3 areas tested in Vale of White HorseOX12 scores 8.6 out of 10, ahead of OX13 in second place on 8.6.
- Very hard water at 258 mg/LThe threshold for very hard is 250 mg/L. Expect visible limescale on taps and in kettles in OX12. How hardness is measured
Questions about OX12 water
Is OX12 tap water safe to drink?
Based on the latest tests, OX12 (Vale of White Horse) 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 OX12 water?
We tested 23 contaminants in OX12 water. 1 were flagged, including Nitrite.
Who supplies water in OX12?
OX12 (Vale of White Horse) is supplied by Thames Water. You can view their full profile and compliance data on our supplier page.
Is OX12 water hard or soft?
Water in OX12 (Vale of White Horse) has a hardness of 258 mg/L CaCO3, which is classified as very hard. Hard water can cause limescale buildup. A water softener or filter jug may help.
Should I use a water filter in OX12?
With 1 contaminant above recommended levels in OX12, 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 OX12 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for OX12, 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 OX12?
The Environment Agency rated the Letcombe Brook as poor for ecological health in its 2025 assessment, meaning the river is badly affected, with much of the expected wildlife missing. It is held back by fish and water plants and algae. 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 OX12, 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
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- 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
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- 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 OX12
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.
Get alerts for your area
We'll email you when water quality data changes for OX12.