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tapwater
England and Wales average 9.0

Tap water in PO21, ArunSafe to drink.

Supplied by Southern Water. 2,836 samples, 21 substances, latest on 16 December 2024. Everything is inside the legal limit, and nothing comes close to it.

See the filter we recommendSee everything that was tested

9.0 / 10

The tank is as full as the score.

What to do about it

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What's in a glass of PO21 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 64% of it. 19 of 20 substances used under a quarter of theirs.

0%25%50%75%limitLegal limitSelenium: 0.0008 mg/L, 2% of the 0.04 mg/L limitSelenium2%Nitrite: 0.011 mg/L, 2% of the 0.5 mg/L limitNitrite2%Antimony: 0.0002 mg/L, 4% of the 0.005 mg/L limitAntimony4%Aluminium: 0.0081 mg/L, 4% of the 0.2 mg/L limitAluminium4%Cadmium: 0.00022 mg/L, 4% of the 0.005 mg/L limitCadmium4%Chromium: 0.0023 mg/L, 5% of the 0.05 mg/L limitChromium5%Lead: 0.0005 mg/L, 5% of the 0.01 mg/L limitLead5%Manganese: 0.0025 mg/L, 5% of the 0.05 mg/L limitManganese5%Nickel: 0.0013 mg/L, 7% of the 0.02 mg/L limitNickel7%Fluoride: 0.099 mg/L, 7% of the 1.5 mg/L limitFluoride7%Iron: 0.0138 mg/L, 7% of the 0.2 mg/L limitIron7%Turbidity: 0.28 NTU, 7% of the 4 NTU limitTurbidity7%Copper: 0.172 mg/L, 9% of the 2 mg/L limitCopper9%Bromate: 0.0009 mg/L, 9% of the 0.01 mg/L limitBromate9%Trihalomethanes: 0.00909 mg/L, 9% of the 0.1 mg/L limitTrihalomethanes9%Colour: 1.93 mg/L Pt/Co, 10% of the 20 mg/L Pt/Co limitColour10%Arsenic: 0.001 mg/L, 10% of the 0.01 mg/L limitArsenic10%Boron: 0.14 mg/L, 14% of the 1 mg/L limitBoron14%Mercury: 0.0002 mg/L, 20% of the 0.001 mg/L limitMercury20%Nitrate: 32.1 mg/L, 64% of the 50 mg/L limitNitrate64%
  1. Nitrate64%
  2. Mercury20%
  3. Boron14%
  4. Arsenic10%
  5. Colour10%
  6. Trihalomethanes9%
  7. Bromate9%
  8. Copper9%
  9. Turbidity7%
  10. Iron7%
  11. Fluoride7%
  12. Nickel7%
  13. Lead5%
  14. Manganese5%
  15. Chromium5%
  16. Cadmium4%
  17. Aluminium4%
  18. Antimony4%
  19. Nitrite2%
  20. Selenium2%
  • Conductivity 518 µS/cm
All 21 results as a table
SubstanceResultLegal limitShare of limit
Aluminium0.0081 mg/L0.2 mg/L
4%
Iron0.0138 mg/L0.2 mg/L
7%
Manganese0.0025 mg/L0.05 mg/L
5%
Turbidity0.28 NTU4 NTU
7%
Conductivity518 µS/cmNo legal limit–
Colour1.93 mg/L Pt/Co20 mg/L Pt/Co
10%
Trihalomethanes0.00909 mg/L0.1 mg/L
9%
Nitrite0.011 mg/L0.5 mg/L
2%
Nitrate32.1 mg/L50 mg/L
64%
Fluoride0.099 mg/L1.5 mg/L
7%
Antimony0.0002 mg/L0.005 mg/L
4%
Arsenic0.001 mg/L0.01 mg/L
10%
Selenium0.0008 mg/L0.04 mg/L
2%
Bromate0.0009 mg/L0.01 mg/L
9%
Lead0.0005 mg/L0.01 mg/L
5%
Nickel0.0013 mg/L0.02 mg/L
7%
Copper0.172 mg/L2 mg/L
9%
Mercury0.0002 mg/L0.001 mg/L
20%
Boron0.14 mg/L1 mg/L
14%
Chromium0.0023 mg/L0.05 mg/L
5%
Cadmium0.00022 mg/L0.005 mg/L
4%
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

PO21 in short

Tap water in PO21 (Arun) is supplied by Southern Water in the Arun Central zone and scores 9.0 out of 10, against an England and Wales average of 9.0. None of the 21 tested substances came close to a limit. The latest sample is from 16 December 2024.

  • The lowest score of the 5 areas tested in ArunPO21 scores 9 out of 10. The best in Arun, BN17, scores 9.4.
  • Every one of the 4 neighbouring districts scores higherBN17 next door scores 9.4, against 9 here. Supply zones, not distance, explain the gap. See BN17
  • Nitrate is the reading closest to its limit, at 64% of the 50 mg/L maximumIt passed with room to spare, and everything else tested sat further below its limit. See every reading

Next door

BN179.4 out of 10BN189.4 out of 10BN169.3 out of 10PO229.3 out of 10

Questions about PO21 water

Is PO21 tap water safe to drink?

Based on the latest tests, PO21 (Arun) water scores 9/10, which is safe. 0 of 21 tested contaminants exceeded recommended levels. Water is supplied by Southern Water.

What contaminants are in PO21 water?

We tested 21 contaminants in PO21 water. None exceeded recommended safe levels.

Who supplies water in PO21?

PO21 (Arun) 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 PO21?

PO21 water scored 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 PO21 water?

No PFAS (forever chemicals) result is attached to the tap-water tests for PO21, 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 coastal water near PO21?

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 PO21, which is treated before it reaches homes.

Keep reading

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

River and groundwater readings near PO21

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
pH8.18 pHNone
Temperature13 °CNone
Conductivity834 µS/cmNone
Nitrate17 mg/L50 mg/L
Nitrite0.071 mg/L0.5 mg/L
Phosphate0.45 mg/LNone
Dissolved Oxygen12.4 mg/LNone
Ammonia0.22 mg/L0.5 mg/L
Aluminium0.0194 mg/L0.2 mg/L
Zinc0.00744 mg/LNone
Copper0.0019 mg/L2 mg/L

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We'll email you when water quality data changes for PO21.

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