Tap water in HP6, BuckinghamshireToo few tap tests to call it.Very hard.
Supplied by Thames Water. 11 substances, latest on 4 September 2026. These are river and groundwater samples near HP6, not tests of treated tap water, so treat the score as a rough guide.
8.4 / 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 299 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 HP6 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.
Iron came closest to a limit, at 100% of it. 4 of 5 substances used under a quarter of theirs.
- Iron100%
- Nitrate10%
- Ammonia7%
- Nitrite5%
- Copper<1%
- pH 7.86 pH
- Temperature 17.6 °C
- Conductivity 611 µS/cm
- Phosphate 0.027 mg/L
- Dissolved Oxygen 9.06 mg/L
- Zinc 0.00804 mg/L
All 11 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Iron | 0.2 mg/L | 0.2 mg/L | 100% |
| pH | 7.86 pH | No legal limit | – |
| Temperature | 17.6 °C | No legal limit | – |
| Conductivity | 611 µS/cm | No legal limit | – |
| Ammonia | 0.036 mg/L | 0.5 mg/L | 7% |
| Nitrate | 4.9 mg/L | 50 mg/L | 10% |
| Nitrite | 0.024 mg/L | 0.5 mg/L | 5% |
| Phosphate | 0.027 mg/L | No legal limit | – |
| Dissolved Oxygen | 9.06 mg/L | No legal limit | – |
| Copper | 0.00161 mg/L | 2 mg/L | <1% |
| Zinc | 0.00804 mg/L | No legal limit | – |
299mg of limescale minerals in every litre, typical for the HP area. HP6 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 HP6
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Your river is the Colne (Confluence with Chess to River Thames), rated moderate
The Environment Agency rated the Colne (Confluence with Chess to River Thames) 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, 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
HP6 in short
Tap water in HP6 (Buckinghamshire) is supplied by Thames Water in the Buckinghamshire Central zone and scores 8.4 out of 10, against an England and Wales average of 9.0. 1 of 11 tested substances was close to or over a limit. The latest sample is from 4 September 2026.
- Iron is within its legal limit but flagged, at 100% of the 0.2 mg/L maximumAnything over three quarters of a limit is flagged here as worth watching. It has not gone over. See every reading
- Very hard water at 299 mg/LThe threshold for very hard is 250 mg/L. Expect visible limescale on taps and in kettles across the HP postcode area. How hardness is measured
- 20th cleanest of 26 areas tested in Buckinghamshire6 areas in Buckinghamshire scored lower. The best is HP19 on 9.3.
Questions about HP6 water
Is HP6 tap water safe to drink?
Based on the latest tests, HP6 (Buckinghamshire) water scores 8.4/10, which is safe. 1 of 11 tested contaminants exceeded recommended levels. Water is supplied by Thames Water.
What contaminants are in HP6 water?
We tested 11 contaminants in HP6 water. 1 were flagged, including Iron.
Who supplies water in HP6?
HP6 (Buckinghamshire) is supplied by Thames Water. You can view their full profile and compliance data on our supplier page.
Is HP6 water hard or soft?
No hardness reading has been published for HP6 itself. Across the HP postcode area the typical value is 299 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 HP6?
With 1 contaminant above recommended levels in HP6, 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 HP6 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for HP6, 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 HP6?
The Environment Agency rated the Colne (Confluence with Chess to River Thames) 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, 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 HP6, which is treated before it reaches homes.
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