Tap water in TN16, SevenoaksToo few tap tests to call it.Very hard.
Supplied by South East Water. 14 substances, latest on 21 September 2026. These are river and groundwater samples near TN16, not tests of treated tap water, so treat the score as a rough guide.
9.8 / 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 330 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 TN16 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.
Manganese came closest to a limit, at 8% of it. 8 of 8 substances used under a quarter of theirs.
- Manganese8%
- Ammonia6%
- Nitrite3%
- Chromium2%
- Nitrate2%
- Nickel<1%
- Lead<1%
- Copper<1%
- Temperature 17.7 °C
- Phosphate 0.019 mg/L
- pH 7.74 pH
- Conductivity 378 µS/cm
- Dissolved Oxygen 8.96 mg/L
- Zinc 0.00021 mg/L
All 14 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 | 7.74 pH | No legal limit | – |
| Conductivity | 378 µS/cm | No legal limit | – |
| Dissolved Oxygen | 8.96 mg/L | No legal limit | – |
| Lead | 0.00005 mg/L | 0.01 mg/L | <1% |
| Chromium | 0.0011 mg/L | 0.05 mg/L | 2% |
| Nickel | 0.00012 mg/L | 0.02 mg/L | <1% |
| Manganese | 0.0041 mg/L | 0.05 mg/L | 8% |
| Copper | 0.00009 mg/L | 2 mg/L | <1% |
| Zinc | 0.00021 mg/L | No legal limit | – |
330mg 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 TN16
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Your river is the Ravensbourne (Keston to Catford), rated moderate
The Environment Agency rated the Ravensbourne (Keston to Catford) 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 insects and other small river life. 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
TN16 in short
Tap water in TN16 (Sevenoaks) is supplied by South East Water in the Sevenoaks Central zone and scores 9.8 out of 10, against an England and Wales average of 9.0. None of the 14 tested substances came close to a limit. The latest sample is from 21 September 2026.
- The cleanest tap water of the 7 areas tested in SevenoaksTN16 scores 9.8 out of 10, ahead of TN14 in second place on 9.7.
- Among the hardest water in the country at 330 mg/LVery hard starts at 250 mg/L. At this level kettles scale up within weeks and a softener is a normal purchase in TN16. How hardness is measured
- Scores higher than all 7 neighbouring districtsThe nearest rival is TN14 on 9.7, against 9.8 here. Compare with TN14
Questions about TN16 water
Is TN16 tap water safe to drink?
Based on the latest tests, TN16 (Sevenoaks) water scores 9.8/10, which is safe. 0 of 14 tested contaminants exceeded recommended levels. Water is supplied by South East Water.
What contaminants are in TN16 water?
We tested 14 contaminants in TN16 water. None exceeded recommended safe levels.
Who supplies water in TN16?
TN16 (Sevenoaks) is supplied by South East Water. You can view their full profile and compliance data on our supplier page.
Is TN16 water hard or soft?
Water in TN16 (Sevenoaks) has a hardness of 330 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 TN16?
TN16 water scored 9.8/10 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 TN16 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for TN16, 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 TN16?
The Environment Agency rated the Ravensbourne (Keston to Catford) 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 insects and other small river life. 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 TN16, which is treated before it reaches homes.
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