Tap water in RG21, Basingstoke and DeaneAmmonia is over the limit.Very hard.
Supplied by Southern Water. 9 substances, latest on 16 September 2026. Ammonia came in above the legal limit. Everything else passed.
7.0 / 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.
Waterdrop G3P600 Reverse Osmosis
£550typical price
Maximum contaminant removal including PFAS and fluoride
Waterdrop 10UA Under Sink
£70typical price
High-volume under-sink filtration without RO complexity
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What's in a glass of RG21 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 is over its legal limit, at 152% of it.
- Ammonia152%
- Nitrite17%
- Nitrate1%
- Cadmium<1%
- pH 8.01 pH
- Temperature 15 °C
- Conductivity 695 µS/cm
- Phosphate 0.092 mg/L
- Dissolved Oxygen 8.94 mg/L
All 9 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Ammonia | 0.76 mg/L | 0.5 mg/L | 152% |
| pH | 8.01 pH | No legal limit | – |
| Temperature | 15 °C | No legal limit | – |
| Conductivity | 695 µS/cm | No legal limit | – |
| Nitrate | 0.6 mg/L | 50 mg/L | 1% |
| Phosphate | 0.092 mg/L | No legal limit | – |
| Dissolved Oxygen | 8.94 mg/L | No legal limit | – |
| Nitrite | 0.083 mg/L | 0.5 mg/L | 17% |
| Cadmium | 0.000025 mg/L | 0.005 mg/L | <1% |
295mg of limescale minerals in every litre, typical for the RG area. RG21 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 RG21
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Your river is the Loddon (Basingstoke to River Lyde confluence at Hartley Wespall), rated poor
The Environment Agency rated the Loddon (Basingstoke to River Lyde confluence at Hartley Wespall) 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
RG21 in short
Tap water in RG21 (Basingstoke and Deane) is supplied by Southern Water in the Basingstoke and Deane Central zone and scores 7.0 out of 10, against an England and Wales average of 9.0. 1 of 9 tested substances was close to or over a limit. The latest sample is from 16 September 2026.
- Ammonia was measured at 0.76 mg/L, 52% over the UK limitIt is the only one of 9 tested substances to go over its limit. See the full results
- The lowest score of the 7 areas tested in Basingstoke and DeaneRG21 scores 7 out of 10. The best in Basingstoke and Deane, RG23, scores 9.4.
- Every one of the 6 neighbouring districts scores higherRG25 next door scores 9.4, against 7 here. Supply zones, not distance, explain the gap. See RG25
Questions about RG21 water
Is RG21 tap water safe to drink?
Based on the latest tests, RG21 (Basingstoke and Deane) water scores 7/10, which is safe. 1 of 9 tested contaminants exceeded recommended levels. Water is supplied by Southern Water.
What contaminants are in RG21 water?
We tested 9 contaminants in RG21 water. 1 were flagged, including Ammonia.
Who supplies water in RG21?
RG21 (Basingstoke and Deane) is supplied by Southern Water. You can view their full profile and compliance data on our supplier page.
Is RG21 water hard or soft?
No hardness reading has been published for RG21 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 RG21?
With 1 contaminant above recommended levels in RG21, 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 RG21 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for RG21, 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 RG21?
The Environment Agency rated the Loddon (Basingstoke to River Lyde confluence at Hartley Wespall) 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 RG21, which is treated before it reaches homes.
Keep reading
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- Softener salt guideTablet, block or granular, and how much you get through
- Salt-free softenersConditioners and electronic descalers, honestly assessed
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