Tap water in RG27, HartToo few tap tests to call it.Very hard.
Supplied by Southern Water. 8 substances, latest on 7 October 2026. These are river and groundwater samples near RG27, not tests of treated tap water, so treat the score as a rough guide.
9.5 / 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 295 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 RG27 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 12% of it. 3 of 3 substances used under a quarter of theirs.
- Ammonia12%
- Nitrate3%
- Nitrite<1%
- pH 7.6 pH
- Temperature 14 °C
- Conductivity 586 µS/cm
- Phosphate 0.065 mg/L
- Dissolved Oxygen 6.53 mg/L
All 8 results as a table
295mg of limescale minerals in every litre, typical for the RG area. RG27 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 RG27
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Your river is the Whitewater, rated poor
The Environment Agency rated the Whitewater 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, water plants and algae and dissolved oxygen. 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
192
forever-chemical detections in nearby rivers and groundwater
At 4 sites. The highest was 6:2 FtSAB at 0.067 µg/L, at Blackwater at Gauging Station, Swallowfield, 8.0 km away, in January 2026. These are river and borehole samples, not tests of your tap water.
Every PFAS sample around Reading · Which filters remove PFAS · PFAS explained
RG27 in short
Tap water in RG27 (Hart) is supplied by Southern Water in the Hart Central zone and scores 9.5 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 7 October 2026.
- The cleanest tap water of the 6 areas tested in HartRG27 scores 9.5 out of 10, ahead of RG29 in second place on 9.3.
- Very hard water at 295 mg/LThe threshold for very hard is 250 mg/L. Expect visible limescale on taps and in kettles across the RG postcode area. How hardness is measured
- Scores higher than all 5 neighbouring districtsThe nearest rival is RG29 on 9.3, against 9.5 here. Compare with RG29
Questions about RG27 water
Is RG27 tap water safe to drink?
Based on the latest tests, RG27 (Hart) water scores 9.5/10, which is safe. 0 of 8 tested contaminants exceeded recommended levels. Water is supplied by Southern Water.
What contaminants are in RG27 water?
We tested 8 contaminants in RG27 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 RG27?
RG27 (Hart) is supplied by Southern Water. You can view their full profile and compliance data on our supplier page.
Is RG27 water hard or soft?
No hardness reading has been published for RG27 itself. Across the RG postcode area the typical value is 295 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 RG27?
RG27 water scored 9.5/10 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 RG27 water?
The tap-water tests we hold for RG27 do not include a PFAS result. Environment Agency monitoring found PFAS in 192 river and groundwater samples from 4 sites within 10 km of RG27, the highest being 6:2 FtSAB at 0.067 µg/L about 8 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 RG27?
The Environment Agency rated the Whitewater 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, water plants and algae and dissolved oxygen. 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 RG27, 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
- 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?
- 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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