Tap water in GU9, WaverleySafe to drink.Very hard.
Supplied by Thames Water. 74 samples, 23 substances, latest on 31 December 2025. Everything is inside the legal limit. One result, nitrite, sits close to the line.
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 204 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 GU9 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.
Nitrite came closest to a limit, at 90% of it. 17 of 19 substances used under a quarter of theirs.
- Nitrite90%
- Nitrate45%
- Trihalomethanes24%
- Copper10%
- Lead10%
- Bromate10%
- Colour9%
- Fluoride8%
- Cadmium8%
- Mercury7%
- Arsenic7%
- Antimony6%
- Nickel6%
- Chromium5%
- Aluminium4%
- Iron4%
- Boron3%
- Selenium2%
- Manganese1%
- Coliform Bacteria none found
- E. coli none found
- Conductivity 434 µS/cm
All 23 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Nitrite | 0.45 mg/L | 0.5 mg/L | 90% |
| Coliform Bacteria | 0 count/100ml | Must be zero | None found |
| E. coli | 0 count/100ml | Must be zero | None found |
| Colour | 1.8 mg/L Pt/Co | 20 mg/L Pt/Co | 9% |
| Conductivity | 434 µS/cm | No legal limit | – |
| Fluoride | 0.12 mg/L | 1.5 mg/L | 8% |
| Nitrate | 22.5 mg/L | 50 mg/L | 45% |
| Hardness (as CaCO3) | 204 mg/L | No legal limit | – |
| Aluminium | 0.0082 mg/L | 0.2 mg/L | 4% |
| Antimony | 0.0003 mg/L | 0.005 mg/L | 6% |
| Arsenic | 0.0007 mg/L | 0.01 mg/L | 7% |
| Boron | 0.03 mg/L | 1 mg/L | 3% |
| Cadmium | 0.0004 mg/L | 0.005 mg/L | 8% |
| Chromium | 0.0025 mg/L | 0.05 mg/L | 5% |
| Copper | 0.2 mg/L | 2 mg/L | 10% |
| Iron | 0.008 mg/L | 0.2 mg/L | 4% |
| Lead | 0.001 mg/L | 0.01 mg/L | 10% |
| Manganese | 0.0006 mg/L | 0.05 mg/L | 1% |
| Mercury | 0.00007 mg/L | 0.001 mg/L | 7% |
| Nickel | 0.0011 mg/L | 0.02 mg/L | 6% |
| Selenium | 0.0007 mg/L | 0.04 mg/L | 2% |
| Trihalomethanes | 0.024 mg/L | 0.1 mg/L | 24% |
| Bromate | 0.001 mg/L | 0.01 mg/L | 10% |
204mg 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 GU9
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Your river is the North Wey (Alton to Tilford), rated moderate
The Environment Agency rated the North Wey (Alton to Tilford) 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 and fish. 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 improved since the previous assessment.
None of this is a test of your tap water. Environment Agency record · River health across England
GU9 in short
Tap water in GU9 (Waverley) is supplied by Thames Water in the Waverley Central zone and scores 8.8 out of 10, against an England and Wales average of 9.0. 1 of 23 tested substances was close to or over a limit. The latest sample is from 31 December 2025.
- Nitrite is within its legal limit but flagged, at 90% of the 0.5 mg/L maximumAnything over three quarters of a limit is flagged here as worth watching. It has not gone over. See every reading
- Hard water at 204 mg/LHard starts at 180 mg/L, the point where a softener begins to pay for itself. Limescale will build up in GU9. How hardness is measured
- 4th cleanest of 7 areas tested in WaverleySquarely mid-table for Waverley, between GU5 on 9.3 and GU7 on 7.8.
Questions about GU9 water
Is GU9 tap water safe to drink?
Based on the latest tests, GU9 (Waverley) water scores 8.8/10, which is safe. 1 of 23 tested contaminants exceeded recommended levels. Water is supplied by Thames Water.
What contaminants are in GU9 water?
We tested 23 contaminants in GU9 water. 1 were flagged, including Nitrite.
Who supplies water in GU9?
GU9 (Waverley) is supplied by Thames Water. You can view their full profile and compliance data on our supplier page.
Is GU9 water hard or soft?
Water in GU9 (Waverley) has a hardness of 204 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 GU9?
With 1 contaminant above recommended levels in GU9, 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 GU9 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for GU9, 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 GU9?
The Environment Agency rated the North Wey (Alton to Tilford) 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 and fish. 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 improved since the previous assessment. This is a rating of the river, not of tap water in GU9, 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?
- Best Water Filters UKEvery filter type compared on what it actually removes
- 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
Nitrate levelsHow to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map
River and groundwater readings near GU9
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.
| Substance | Reading | Drinking water limit |
|---|---|---|
| pH | 7.63 pH | None |
| Temperature | 19 °C | None |
| Conductivity | 565 µS/cm | None |
| Ammonia | 0.071 mg/L | 0.5 mg/L |
| Nitrate | 1.2 mg/L | 50 mg/L |
| Nitrite | 0.023 mg/L | 0.5 mg/L |
| Phosphate | 0.14 mg/L | None |
| Dissolved Oxygen | 5.22 mg/L | None |
| Lead | 0.000436 mg/L | 0.01 mg/L |
| Zinc | 0.0256 mg/L | None |
| Chromium | 0.000941 mg/L | 0.05 mg/L |
| Copper | 0.00625 mg/L | 2 mg/L |
| Manganese | 0.0175 mg/L | 0.05 mg/L |
| Iron | 0.0533 mg/L | 0.2 mg/L |
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