Tap water in GL12, South GloucestershireToo few tap tests to call it.Very hard.
Supplied by Bristol Water. 8 substances, latest on 5 October 2026. These are river and groundwater samples near GL12, not tests of treated tap water, so treat the score as a rough guide.
8.8 / 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.
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 GL12 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.
Ammonia came closest to a limit, at 34% of it. 2 of 3 substances used under a quarter of theirs.
- Ammonia34%
- Nitrite3%
- Nitrate<1%
- pH 7.94 pH
- Temperature 14.1 °C
- Conductivity 717 µS/cm
- Phosphate 0.12 mg/L
- Dissolved Oxygen 8.06 mg/L
All 8 results as a table
258mg of limescale minerals in every litre, typical for the GL area. GL12 has no reading of its own.
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 GL12
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Your river is the Little Avon R - source to conf Ozleworth Bk, rated poor
The Environment Agency rated the Little Avon R - source to conf Ozleworth Bk 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 water plants and algae and 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.
None of this is a test of your tap water. Environment Agency record · River health across England
4
forever-chemical detections in nearby rivers and groundwater
At 1 site. The highest was PFOS (total) at 0.0014 µg/L, at Game Farm, Latteridge, 9.4 km away, in March 2026. These are river and borehole samples, not tests of your tap water.
Every PFAS sample around Bristol · Which filters remove PFAS · PFAS explained
GL12 in short
Tap water in GL12 (South Gloucestershire) is supplied by Bristol Water in the South Gloucestershire Central zone and scores 8.8 out of 10, against an England and Wales average of 9.0. None of the 8 tested substances came close to a limit. The latest sample is from 5 October 2026.
- The lowest score of the 9 areas tested in South GloucestershireGL12 scores 8.8 out of 10. The best in South Gloucestershire, BS37, scores 9.6.
- Every one of the 8 neighbouring districts scores higherBS37 next door scores 9.6, against 8.8 here. Supply zones, not distance, explain the gap. See BS37
- Very hard water at 258 mg/LThe threshold for very hard is 250 mg/L. Expect visible limescale on taps and in kettles across the GL postcode area. How hardness is measured
Questions about GL12 water
Is GL12 tap water safe to drink?
Based on the latest tests, GL12 (South Gloucestershire) water scores 8.8/10, which is safe. 0 of 8 tested contaminants exceeded recommended levels. Water is supplied by Bristol Water.
What contaminants are in GL12 water?
We tested 8 contaminants in GL12 water. None exceeded recommended safe levels. PFAS (forever chemicals) were also measured in rivers and groundwater within 10 km, though not in the tap-water tests themselves.
Who supplies water in GL12?
GL12 (South Gloucestershire) is supplied by Bristol Water. You can view their full profile and compliance data on our supplier page.
Is GL12 water hard or soft?
No hardness reading has been published for GL12 itself. Across the GL postcode area the typical value is 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 GL12?
GL12 water scored 8.8/10 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 GL12 water?
The tap-water tests we hold for GL12 do not include a PFAS result. Environment Agency monitoring found PFAS in 4 river and groundwater samples from 1 sites within 10 km of GL12, the highest being PFOS (total) at 0.0014 µg/L about 9.4 km away. These are environmental samples, not tests of tap water. The UK currently has no legal limit for PFAS in drinking water; the Drinking Water Inspectorate uses a 0.1 µg/L guideline for individual compounds. Reverse osmosis filters can reduce PFAS levels.
How clean is the river near GL12?
The Environment Agency rated the Little Avon R - source to conf Ozleworth Bk 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 water plants and algae and 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. This is a rating of the river, not of tap water in GL12, which is treated before it reaches homes.
Keep reading
- Best Filter for PFAS RemovalThe filters with independent certification to remove forever chemicals
- PFAS Forever ChemicalsWhat PFAS are and how to reduce your exposure at home
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- 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?
- 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
PFAS explainedBoiling water taps and hard waterHow to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map
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