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tapwater
England and Wales average 9.0

Tap water in BN10, LewesSafe to drink.

Supplied by Southern Water. 3,352 samples, 22 substances, latest on 2 April 2026. Everything is inside the legal limit, and nothing comes close to it.

See the filter we recommendSee everything that was tested

9.3 / 10

The tank is as full as the score.

What to do about it

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What's in a glass of BN10 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 67% of it. 17 of 18 substances used under a quarter of theirs.

0%25%50%75%limitLegal limitCopper: 0.0146 mg/L, <1% of the 2 mg/L limitCopper<1%Nitrite: 0.004 mg/L, <1% of the 0.5 mg/L limitNitrite<1%Selenium: 0.00032 mg/L, <1% of the 0.04 mg/L limitSelenium<1%Bromate: 0.00013 mg/L, 1% of the 0.01 mg/L limitBromate1%Arsenic: 0.00015 mg/L, 1% of the 0.01 mg/L limitArsenic1%Chromium: 0.001 mg/L, 2% of the 0.05 mg/L limitChromium2%Cadmium: 0.00012 mg/L, 2% of the 0.005 mg/L limitCadmium2%Turbidity: 0.13 NTU, 3% of the 4 NTU limitTurbidity3%Manganese: 0.00178 mg/L, 4% of the 0.05 mg/L limitManganese4%Lead: 0.0004 mg/L, 4% of the 0.01 mg/L limitLead4%Antimony: 0.0002 mg/L, 4% of the 0.005 mg/L limitAntimony4%Iron: 0.00928 mg/L, 5% of the 0.2 mg/L limitIron5%Ammonia: 0.025 mg/L, 5% of the 0.5 mg/L limitAmmonia5%Aluminium: 0.0113 mg/L, 6% of the 0.2 mg/L limitAluminium6%Nickel: 0.00168 mg/L, 8% of the 0.02 mg/L limitNickel8%Colour: 3 mg/L Pt/Co, 15% of the 20 mg/L Pt/Co limitColour15%Trihalomethanes: 0.0152 mg/L, 15% of the 0.1 mg/L limitTrihalomethanes15%Nitrate: 33.7 mg/L, 67% of the 50 mg/L limitNitrate67%
  1. Nitrate67%
  2. Trihalomethanes15%
  3. Colour15%
  4. Nickel8%
  5. Aluminium6%
  6. Ammonia5%
  7. Iron5%
  8. Lead4%
  9. Antimony4%
  10. Manganese4%
  11. Turbidity3%
  12. Cadmium2%
  13. Chromium2%
  14. Arsenic1%
  15. Bromate1%
  16. Nitrite<1%
  17. Selenium<1%
  18. Copper<1%
  • Coliform Bacteria none found
  • E. coli none found
  • pH 7.7 pH
  • Conductivity 487 µS/cm
All 22 results as a table
SubstanceResultLegal limitShare of limit
Aluminium0.0113 mg/L0.2 mg/L
6%
Iron0.00928 mg/L0.2 mg/L
5%
Manganese0.00178 mg/L0.05 mg/L
4%
Coliform Bacteria0 count/100mlMust be zeroNone found
E. coli0 count/100mlMust be zeroNone found
Colour3 mg/L Pt/Co20 mg/L Pt/Co
15%
Turbidity0.13 NTU4 NTU
3%
pH7.7 pHNo legal limit–
Nitrate33.7 mg/L50 mg/L
67%
Nitrite0.004 mg/L0.5 mg/L
<1%
Lead0.0004 mg/L0.01 mg/L
4%
Trihalomethanes0.0152 mg/L0.1 mg/L
15%
Conductivity487 µS/cmNo legal limit–
Bromate0.00013 mg/L0.01 mg/L
1%
Ammonia0.025 mg/L0.5 mg/L
5%
Copper0.0146 mg/L2 mg/L
<1%
Arsenic0.00015 mg/L0.01 mg/L
1%
Cadmium0.00012 mg/L0.005 mg/L
2%
Chromium0.001 mg/L0.05 mg/L
2%
Nickel0.00168 mg/L0.02 mg/L
8%
Antimony0.0002 mg/L0.005 mg/L
4%
Selenium0.00032 mg/L0.04 mg/L
<1%
Outside your tap

Your coastal water is the Sussex, rated moderate

The Environment Agency rated the Sussex as moderate for ecological health in its 2025 assessment, meaning the coastal water is noticeably changed by pollution or engineering. 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

Within 10 km

7

forever-chemical detections in nearby rivers and groundwater

At 1 site. The highest was PFBA at 0.0037 µg/L, at Brighton College, Ground Source Heat Pump, 9.1 km away, in October 2025. These are river and borehole samples, not tests of your tap water.

Every PFAS sample around Brighton · Which filters remove PFAS · PFAS explained

BN10 in short

Tap water in BN10 (Lewes) is supplied by Southern Water in the Lewes 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 2 April 2026.

  • The cleanest tap water of the 5 areas tested in LewesBN10 scores 9.3 out of 10, ahead of BN7 in second place on 9.3.
  • Nitrate is the reading closest to its limit, at 67% of the 50 mg/L maximumIt passed with room to spare, and everything else tested sat further below its limit. See every reading
  • PFAS found at 1 monitoring site within 10 kmThose are river and groundwater samples, not tap water. The highest was PFBA about 9.1 km away. What was measured

Next door

BN89.2 out of 10BN259.0 out of 10BN99.3 out of 10BN79.3 out of 10

Questions about BN10 water

Is BN10 tap water safe to drink?

Based on the latest tests, BN10 (Lewes) 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 BN10 water?

We tested 22 contaminants in BN10 water. None exceeded recommended safe levels. PFAS (forever chemicals) were also measured in rivers and groundwater within 10 km, though not in the tap-water tests themselves.

Who supplies water in BN10?

BN10 (Lewes) 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 BN10?

BN10 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 BN10 water?

The tap-water tests we hold for BN10 do not include a PFAS result. Environment Agency monitoring found PFAS in 7 river and groundwater samples from 1 sites within 10 km of BN10, the highest being PFBA at 0.0037 µg/L about 9.1 km away. These are environmental samples, not tests of tap water. The UK currently has no legal limit for PFAS in drinking water; the Drinking Water Inspectorate uses a 0.1 µg/L guideline for individual compounds. Reverse osmosis filters can reduce PFAS levels.

How clean is the coastal water near BN10?

The Environment Agency rated the Sussex as moderate for ecological health in its 2025 assessment, meaning the coastal water is noticeably changed by pollution or engineering. 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 coastal water, not of tap water in BN10, which is treated before it reaches homes.

Keep reading

PFAS explainedHow to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map

River and groundwater readings near BN10

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.

SubstanceReadingDrinking water limit
pH7.53 pHNone
Temperature16.3 °CNone
Conductivity676 µS/cmNone
Nitrate10 mg/L50 mg/L
Phosphate0.079 mg/LNone
Dissolved Oxygen8.93 mg/LNone
Ammonia0.095 mg/L0.5 mg/L
Nitrite0.085 mg/L0.5 mg/L
Copper0.000801 mg/L2 mg/L
Zinc0.00223 mg/LNone

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We'll email you when water quality data changes for BN10.

Source: Southern Water test results, published through the Stream Water Data Portal; rivers and PFAS from the Environment Agency. Page updated . How we score · Where the data comes from