Tap water in BN5, HorshamSafe to drink.
Supplied by Southern Water. 8,186 samples, 22 substances, latest on 30 April 2026. Everything is inside the legal limit, and nothing comes close to it.
9.3 / 10
The tank is as full as the score.
What to do about it
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
BRITA Marella XL + MAXTRA PRO
£25typical price
Basic chlorine and taste improvement on a budget
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What's in a glass of BN5 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.
Nitrate came closest to a limit, at 61% of it. 17 of 18 substances used under a quarter of theirs.
- Nitrate61%
- Trihalomethanes16%
- Colour15%
- Arsenic10%
- Bromate8%
- Aluminium6%
- Ammonia5%
- Nickel5%
- Iron5%
- Manganese4%
- Turbidity3%
- Cadmium2%
- Chromium2%
- Antimony2%
- Selenium2%
- Copper2%
- Lead<1%
- Nitrite<1%
- pH 7.6 pH
- Conductivity 498 µS/cm
- E. coli none found
- Coliform Bacteria none found
All 22 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| pH | 7.6 pH | No legal limit | – |
| Nitrate | 30.3 mg/L | 50 mg/L | 61% |
| Aluminium | 0.0113 mg/L | 0.2 mg/L | 6% |
| Iron | 0.00928 mg/L | 0.2 mg/L | 5% |
| Manganese | 0.00178 mg/L | 0.05 mg/L | 4% |
| Lead | 0.00009 mg/L | 0.01 mg/L | <1% |
| Conductivity | 498 µS/cm | No legal limit | – |
| E. coli | 0 count/100ml | Must be zero | None found |
| Coliform Bacteria | 0 count/100ml | Must be zero | None found |
| Colour | 3 mg/L Pt/Co | 20 mg/L Pt/Co | 15% |
| Turbidity | 0.13 NTU | 4 NTU | 3% |
| Ammonia | 0.025 mg/L | 0.5 mg/L | 5% |
| Nitrite | 0.004 mg/L | 0.5 mg/L | <1% |
| Copper | 0.0317 mg/L | 2 mg/L | 2% |
| Arsenic | 0.001 mg/L | 0.01 mg/L | 10% |
| Cadmium | 0.00012 mg/L | 0.005 mg/L | 2% |
| Chromium | 0.001 mg/L | 0.05 mg/L | 2% |
| Nickel | 0.001 mg/L | 0.02 mg/L | 5% |
| Antimony | 0.0001 mg/L | 0.005 mg/L | 2% |
| Selenium | 0.0008 mg/L | 0.04 mg/L | 2% |
| Trihalomethanes | 0.0157 mg/L | 0.1 mg/L | 16% |
| Bromate | 0.0008 mg/L | 0.01 mg/L | 8% |
Your river is the Chess Stream, rated moderate
The Environment Agency rated the Chess Stream as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by water plants and algae and phosphate. 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
BN5 in short
Tap water in BN5 (Horsham) is supplied by Southern Water in the Horsham Central zone and scores 9.3 out of 10, against an England and Wales average of 9.0. None of the 22 tested substances came close to a limit. The latest sample is from 30 April 2026.
- Nitrate is the reading closest to its limit, at 61% of the 50 mg/L maximumIt passed with room to spare, and everything else tested sat further below its limit. See every reading
- 2nd cleanest of 5 areas tested in HorshamOnly 1 area in Horsham scored higher. The best is BN44 on 9.4.
- Scores higher than 0 of 4 neighbouring districtsWater here is typical for the immediate area, which usually means the same treatment works and the same supply zone.
Questions about BN5 water
Is BN5 tap water safe to drink?
Based on the latest tests, BN5 (Horsham) water scores 9.3/10, which is safe. 0 of 22 tested contaminants exceeded recommended levels. Water is supplied by Southern Water.
What contaminants are in BN5 water?
We tested 22 contaminants in BN5 water. None exceeded recommended safe levels.
Who supplies water in BN5?
BN5 (Horsham) is supplied by Southern Water. You can view their full profile and compliance data on our supplier page.
Should I use a water filter in BN5?
BN5 water scored 9.3/10 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 BN5 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for BN5, 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 BN5?
The Environment Agency rated the Chess Stream as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by water plants and algae and phosphate. 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 BN5, 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
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- 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
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River and groundwater readings near BN5
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 BN5.