Tap water in TN14, SevenoaksToo few tap tests to call it.Very hard.
Supplied by South East Water. 10 substances, latest on 21 September 2026. These are river and groundwater samples near TN14, not tests of treated tap water, so treat the score as a rough guide.
9.7 / 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 301 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 TN14 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 6% of it. 4 of 4 substances used under a quarter of theirs.
- Ammonia6%
- Nitrite3%
- Nitrate2%
- Copper<1%
- Temperature 17.7 °C
- Phosphate 0.019 mg/L
- pH 7.92 pH
- Conductivity 522 µS/cm
- Dissolved Oxygen 9.8 mg/L
- Zinc 0.00513 mg/L
All 10 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Temperature | 17.7 °C | No legal limit | – |
| Ammonia | 0.03 mg/L | 0.5 mg/L | 6% |
| Nitrate | 0.98 mg/L | 50 mg/L | 2% |
| Nitrite | 0.014 mg/L | 0.5 mg/L | 3% |
| Phosphate | 0.019 mg/L | No legal limit | – |
| pH | 7.92 pH | No legal limit | – |
| Conductivity | 522 µS/cm | No legal limit | – |
| Dissolved Oxygen | 9.8 mg/L | No legal limit | – |
| Zinc | 0.00513 mg/L | No legal limit | – |
| Copper | 0.00212 mg/L | 2 mg/L | <1% |
301mg 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 TN14
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Your river is the Upper Darent, rated moderate
The Environment Agency rated the Upper Darent as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. 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
TN14 in short
Tap water in TN14 (Sevenoaks) is supplied by South East Water in the Sevenoaks Central zone and scores 9.7 out of 10, against an England and Wales average of 9.0. None of the 10 tested substances came close to a limit. The latest sample is from 21 September 2026.
- Among the hardest water in the country at 301 mg/LVery hard starts at 250 mg/L. At this level kettles scale up within weeks and a softener is a normal purchase in TN14. How hardness is measured
- 2nd cleanest of 7 areas tested in SevenoaksOnly 1 area in Sevenoaks scored higher. The best is TN16 on 9.8.
- 0.7 points above the national average of 9Cleaner than the typical tested district in the UK. Compare every area
Questions about TN14 water
Is TN14 tap water safe to drink?
Based on the latest tests, TN14 (Sevenoaks) water scores 9.7/10, which is safe. 0 of 10 tested contaminants exceeded recommended levels. Water is supplied by South East Water.
What contaminants are in TN14 water?
We tested 10 contaminants in TN14 water. None exceeded recommended safe levels.
Who supplies water in TN14?
TN14 (Sevenoaks) is supplied by South East Water. You can view their full profile and compliance data on our supplier page.
Is TN14 water hard or soft?
Water in TN14 (Sevenoaks) has a hardness of 301 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 TN14?
TN14 water scored 9.7/10 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 TN14 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for TN14, 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 TN14?
The Environment Agency rated the Upper Darent as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. 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 TN14, which is treated before it reaches homes.
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