Tap water in GL9, CotswoldSafe to drink.Very hard.
Supplied by Severn Trent. 42 samples, 20 substances, latest on 10 November 2025. Everything is inside the legal limit, and nothing comes close to it.
9.6 / 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 241 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.
ZeroWater 12-Cup Ready-Pour
£40typical price
Households concerned about PFAS and heavy metals
Waterdrop 10UA Under Sink
£70typical price
High-volume under-sink filtration without RO complexity
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What's in a glass of GL9 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.
Nitrate came closest to a limit, at 18% of it. 17 of 17 substances used under a quarter of theirs.
- Nitrate18%
- Fluoride12%
- Nickel5%
- Aluminium5%
- Colour4%
- Trihalomethanes4%
- Turbidity3%
- Nitrite3%
- Iron2%
- Manganese2%
- Arsenic1%
- Lead1%
- Copper1%
- Antimony1%
- Chromium<1%
- Selenium<1%
- Cadmium<1%
- pH 7.46 pH
- Conductivity 564 µS/cm
- Phosphate 0.791 mg/L
All 20 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Nitrate | 9.1 mg/L | 50 mg/L | 18% |
| Nitrite | 0.013 mg/L | 0.5 mg/L | 3% |
| Aluminium | 0.0094 mg/L | 0.2 mg/L | 5% |
| Iron | 0.0037 mg/L | 0.2 mg/L | 2% |
| Manganese | 0.00076 mg/L | 0.05 mg/L | 2% |
| Copper | 0.0249 mg/L | 2 mg/L | 1% |
| Fluoride | 0.18 mg/L | 1.5 mg/L | 12% |
| Arsenic | 0.00014 mg/L | 0.01 mg/L | 1% |
| Cadmium | 0.00002 mg/L | 0.005 mg/L | <1% |
| Chromium | 0.00042 mg/L | 0.05 mg/L | <1% |
| Nickel | 0.001 mg/L | 0.02 mg/L | 5% |
| Lead | 0.00014 mg/L | 0.01 mg/L | 1% |
| Antimony | 0.000059 mg/L | 0.005 mg/L | 1% |
| Selenium | 0.00018 mg/L | 0.04 mg/L | <1% |
| Trihalomethanes | 0.00391 mg/L | 0.1 mg/L | 4% |
| Colour | 0.8 mg/L Pt/Co | 20 mg/L Pt/Co | 4% |
| Turbidity | 0.12 NTU | 4 NTU | 3% |
| pH | 7.46 pH | No legal limit | – |
| Conductivity | 564 µS/cm | No legal limit | – |
| Phosphate | 0.791 mg/L | No legal limit | – |
241mg 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 GL9
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Your river is the Luckington Bk, rated moderate
The Environment Agency rated the Luckington Bk 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. 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. Its ecological rating has dropped since the previous assessment.
None of this is a test of your tap water. Environment Agency record · River health across England
GL9 in short
Tap water in GL9 (Cotswold) is supplied by Severn Trent in the Cotswold Central zone and scores 9.6 out of 10, against an England and Wales average of 9.0. None of the 20 tested substances came close to a limit. The latest sample is from 10 November 2025.
- Hard water at 241 mg/LHard starts at 180 mg/L, the point where a softener begins to pay for itself. Limescale will build up in GL9. How hardness is measured
- 2nd cleanest of 5 areas tested in CotswoldOnly 1 area in Cotswold scored higher. The best is GL56 on 9.6.
- 0.6 points above the national average of 9Cleaner than the typical tested district in the UK. Compare every area
Questions about GL9 water
Is GL9 tap water safe to drink?
Based on the latest tests, GL9 (Cotswold) water scores 9.6/10, which is safe. 0 of 20 tested contaminants exceeded recommended levels. Water is supplied by Severn Trent.
What contaminants are in GL9 water?
We tested 20 contaminants in GL9 water. None exceeded recommended safe levels.
Who supplies water in GL9?
GL9 (Cotswold) is supplied by Severn Trent. You can view their full profile and compliance data on our supplier page.
Is GL9 water hard or soft?
Water in GL9 (Cotswold) has a hardness of 241 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 GL9?
GL9 water scored 9.6/10 with no contaminants above recommended levels. A filter is optional but can improve taste, especially if you notice a chlorine flavour. See our filter recommendations for your area.
Are there PFAS forever chemicals in GL9 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for GL9, 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 GL9?
The Environment Agency rated the Luckington Bk 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. 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. Its ecological rating has dropped since the previous assessment. This is a rating of the river, not of tap water in GL9, 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?
- Is UK Tap Water Safe?Everything you need to know about tap water safety in the UK
- 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
How to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map
River and groundwater readings near GL9
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 GL9.