Tap water in RH7, TandridgeSafe 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.
8.6 / 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 225 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 RH7 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 98% of it. 17 of 19 substances used under a quarter of theirs.
- Nitrite98%
- Nitrate49%
- Lead23%
- Trihalomethanes20%
- Copper12%
- Bromate10%
- Fluoride9%
- Colour9%
- Cadmium8%
- Mercury7%
- Arsenic7%
- Antimony6%
- Nickel5%
- Chromium5%
- Aluminium4%
- Boron4%
- Iron4%
- Selenium3%
- Manganese2%
- Coliform Bacteria none found
- E. coli none found
- Conductivity 514 µS/cm
All 23 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Nitrite | 0.49 mg/L | 0.5 mg/L | 98% |
| 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 | 514 µS/cm | No legal limit | – |
| Fluoride | 0.14 mg/L | 1.5 mg/L | 9% |
| Nitrate | 24.7 mg/L | 50 mg/L | 49% |
| Hardness (as CaCO3) | 225 mg/L | No legal limit | – |
| Aluminium | 0.0083 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 | 0.04 mg/L | 1 mg/L | 4% |
| Cadmium | 0.0004 mg/L | 0.005 mg/L | 8% |
| Chromium | 0.0025 mg/L | 0.05 mg/L | 5% |
| Copper | 0.23 mg/L | 2 mg/L | 12% |
| Iron | 0.008 mg/L | 0.2 mg/L | 4% |
| Lead | 0.0023 mg/L | 0.01 mg/L | 23% |
| Manganese | 0.0012 mg/L | 0.05 mg/L | 2% |
| Mercury | 0.00007 mg/L | 0.001 mg/L | 7% |
| Nickel | 0.001 mg/L | 0.02 mg/L | 5% |
| Selenium | 0.001 mg/L | 0.04 mg/L | 3% |
| Trihalomethanes | 0.02 mg/L | 0.1 mg/L | 20% |
| Bromate | 0.001 mg/L | 0.01 mg/L | 10% |
225mg 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 RH7
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Your river is the Eden Brook, rated moderate
The Environment Agency rated the Eden Brook 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 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. 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
RH7 in short
Tap water in RH7 (Tandridge) is supplied by Thames Water in the Tandridge Central zone and scores 8.6 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 98% 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 225 mg/LHard starts at 180 mg/L, the point where a softener begins to pay for itself. Limescale will build up in RH7. How hardness is measured
- 3rd cleanest of 5 areas tested in TandridgeSquarely mid-table for Tandridge, between RH9 on 8.8 and RH8 on 7.8.
Questions about RH7 water
Is RH7 tap water safe to drink?
Based on the latest tests, RH7 (Tandridge) water scores 8.6/10, which is safe. 1 of 23 tested contaminants exceeded recommended levels. Water is supplied by Thames Water.
What contaminants are in RH7 water?
We tested 23 contaminants in RH7 water. 1 were flagged, including Nitrite.
Who supplies water in RH7?
RH7 (Tandridge) is supplied by Thames Water. You can view their full profile and compliance data on our supplier page.
Is RH7 water hard or soft?
Water in RH7 (Tandridge) has a hardness of 225 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 RH7?
With 1 contaminant above recommended levels in RH7, 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 RH7 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for RH7, 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 RH7?
The Environment Agency rated the Eden Brook 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 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. Its ecological rating has improved since the previous assessment. This is a rating of the river, not of tap water in RH7, which is treated before it reaches homes.
Keep reading
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- UK Water Hardness MapIs your water hard or soft, and does it matter?
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- 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 RH7
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.
Get alerts for your area
We'll email you when water quality data changes for RH7.