Tap water in TN11, Tonbridge and MallingToo few tap tests to call it.Slightly hard.
Supplied by Southern Water. 10 substances, latest on 27 August 2026. These are river and groundwater samples near TN11, not tests of treated tap water, so treat the score as a rough guide.
6.9 / 10
The tank is as full as the score. The specks are the minerals that make water hard.
What to do about it
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BRITA Marella XL + MAXTRA PRO
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Basic chlorine and taste improvement on a budget
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What's in a glass of TN11 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 55% of it. 2 of 5 substances used under a quarter of theirs.
- Iron55%
- Ammonia42%
- Turbidity40%
- Nitrite22%
- Nitrate13%
- pH 8.36 pH
- Temperature 23.6 °C
- Conductivity 583 µS/cm
- Phosphate 0.27 mg/L
- Dissolved Oxygen 6.52 mg/L
All 10 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| pH | 8.36 pH | No legal limit | – |
| Temperature | 23.6 °C | No legal limit | – |
| Conductivity | 583 µS/cm | No legal limit | – |
| Ammonia | 0.21 mg/L | 0.5 mg/L | 42% |
| Nitrate | 6.4 mg/L | 50 mg/L | 13% |
| Nitrite | 0.11 mg/L | 0.5 mg/L | 22% |
| Phosphate | 0.27 mg/L | No legal limit | – |
| Turbidity | 1.6 NTU | 4 NTU | 40% |
| Dissolved Oxygen | 6.52 mg/L | No legal limit | – |
| Iron | 0.11 mg/L | 0.2 mg/L | 55% |
150mg of limescale minerals in every litre, typical for the TN area. TN11 has no reading of its own.
Middling hardness. Some scale, slowly
Below the point where a softener pays for itself. Descaling the kettle now and then is all most homes need.
Your river is the Hilden Brook, rated moderate
The Environment Agency rated the Hilden 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 dissolved oxygen, water plants and algae and ammonia. 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
TN11 in short
Tap water in TN11 (Tonbridge and Malling) is supplied by Southern Water in the Tonbridge and Malling Central zone and scores 6.9 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 27 August 2026.
- 6th cleanest of 7 areas tested in Tonbridge and Malling1 area in Tonbridge and Malling scored lower. The best is TN15 on 9.5.
- Iron is the reading closest to its limit, at 55% of the 0.2 mg/L maximumIt passed with room to spare, and everything else tested sat further below its limit. See every reading
- 2.1 points below the national average of 9Below the typical tested district in the UK, which is worth knowing before you choose a filter. Compare every area
Questions about TN11 water
Is TN11 tap water safe to drink?
Based on the latest tests, TN11 (Tonbridge and Malling) water scores 6.9/10, which is mostly safe but has some issues. 0 of 10 tested contaminants exceeded recommended levels. Water is supplied by Southern Water.
What contaminants are in TN11 water?
We tested 10 contaminants in TN11 water. None exceeded recommended safe levels.
Who supplies water in TN11?
TN11 (Tonbridge and Malling) is supplied by Southern Water. You can view their full profile and compliance data on our supplier page.
Is TN11 water hard or soft?
No hardness reading has been published for TN11 itself. Across the TN postcode area the typical value is 150 mg/L CaCO3, which is classified as moderately hard. This is a moderate hardness level.
Should I use a water filter in TN11?
TN11 water scored 6.9/10 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 TN11 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for TN11, 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 TN11?
The Environment Agency rated the Hilden 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 dissolved oxygen, water plants and algae and ammonia. 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 TN11, which is treated before it reaches homes.
Keep reading
- Is UK Tap Water Safe?Everything you need to know about tap water safety in the UK
- Best Water Filters UKEvery filter type compared on what it actually removes
- How to Test Your Tap WaterFrom DIY strips to professional lab analysis
- Best Water Filter Jug UKBRITA vs ZeroWater vs the rest, tested against real data
How to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map
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