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tapwater
England and Wales average 9.0

Tap water in CT21, Folkestone and HytheSafe to drink.

Supplied by Southern Water. 440 samples, 24 substances, latest on 16 December 2025. Everything is inside the legal limit, and nothing comes close to it.

See the filter we recommendSee everything that was tested

9.4 / 10

The tank is as full as the score.

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What's in a glass of CT21 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 52% of it. 20 of 21 substances used under a quarter of theirs.

0%25%50%75%limitLegal limitAntimony: 0.000027 mg/L, <1% of the 0.005 mg/L limitAntimony<1%Manganese: 0.000435 mg/L, <1% of the 0.05 mg/L limitManganese<1%Chromium: 0.000438 mg/L, <1% of the 0.05 mg/L limitChromium<1%Selenium: 0.000352 mg/L, <1% of the 0.04 mg/L limitSelenium<1%Aluminium: 0.00199 mg/L, <1% of the 0.2 mg/L limitAluminium<1%Cadmium: 0.000054 mg/L, 1% of the 0.005 mg/L limitCadmium1%Copper: 0.032 mg/L, 2% of the 2 mg/L limitCopper2%Arsenic: 0.000191 mg/L, 2% of the 0.01 mg/L limitArsenic2%Nitrite: 0.01 mg/L, 2% of the 0.5 mg/L limitNitrite2%Mercury: 0.000023 mg/L, 2% of the 0.001 mg/L limitMercury2%Turbidity: 0.1 NTU, 3% of the 4 NTU limitTurbidity3%Nickel: 0.000611 mg/L, 3% of the 0.02 mg/L limitNickel3%Iron: 0.00897 mg/L, 4% of the 0.2 mg/L limitIron4%Boron: 0.046 mg/L, 5% of the 1 mg/L limitBoron5%Fluoride: 0.085 mg/L, 6% of the 1.5 mg/L limitFluoride6%Trihalomethanes: 0.00649 mg/L, 6% of the 0.1 mg/L limitTrihalomethanes6%Lead: 0.000673 mg/L, 7% of the 0.01 mg/L limitLead7%Colour: 2 mg/L Pt/Co, 10% of the 20 mg/L Pt/Co limitColour10%Ammonia: 0.06 mg/L, 12% of the 0.5 mg/L limitAmmonia12%Bromate: 0.00147 mg/L, 15% of the 0.01 mg/L limitBromate15%Nitrate: 25.8 mg/L, 52% of the 50 mg/L limitNitrate52%
  1. Nitrate52%
  2. Bromate15%
  3. Ammonia12%
  4. Colour10%
  5. Lead7%
  6. Trihalomethanes6%
  7. Fluoride6%
  8. Boron5%
  9. Iron4%
  10. Nickel3%
  11. Turbidity3%
  12. Mercury2%
  13. Nitrite2%
  14. Arsenic2%
  15. Copper2%
  16. Cadmium1%
  17. Aluminium<1%
  18. Selenium<1%
  19. Chromium<1%
  20. Manganese<1%
  21. Antimony<1%
  • Coliform Bacteria none found
  • E. coli none found
  • Conductivity 526 µS/cm
All 24 results as a table
SubstanceResultLegal limitShare of limit
Coliform Bacteria0 count/100mlMust be zeroNone found
Aluminium0.00199 mg/L0.2 mg/L
<1%
Copper0.032 mg/L2 mg/L
2%
E. coli0 count/100mlMust be zeroNone found
Conductivity526 µS/cmNo legal limit–
Nitrite0.01 mg/L0.5 mg/L
2%
Nitrate25.8 mg/L50 mg/L
52%
Selenium0.000352 mg/L0.04 mg/L
<1%
Trihalomethanes0.00649 mg/L0.1 mg/L
6%
Lead0.000673 mg/L0.01 mg/L
7%
Ammonia0.06 mg/L0.5 mg/L
12%
Colour2 mg/L Pt/Co20 mg/L Pt/Co
10%
Antimony0.000027 mg/L0.005 mg/L
<1%
Turbidity0.1 NTU4 NTU
3%
Nickel0.000611 mg/L0.02 mg/L
3%
Bromate0.00147 mg/L0.01 mg/L
15%
Cadmium0.000054 mg/L0.005 mg/L
1%
Arsenic0.000191 mg/L0.01 mg/L
2%
Boron0.046 mg/L1 mg/L
5%
Iron0.00897 mg/L0.2 mg/L
4%
Chromium0.000438 mg/L0.05 mg/L
<1%
Fluoride0.085 mg/L1.5 mg/L
6%
Mercury0.000023 mg/L0.001 mg/L
2%
Manganese0.000435 mg/L0.05 mg/L
<1%
Outside your tap

Your coastal water is the Kent South, rated moderate

The Environment Agency rated the Kent South 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

CT21 in short

Tap water in CT21 (Folkestone and Hythe) is supplied by Southern Water in the Folkestone and Hythe Central zone and scores 9.4 out of 10, against an England and Wales average of 9.0. None of the 24 tested substances came close to a limit. The latest sample is from 16 December 2025.

  • Nitrate is the reading closest to its limit, at 52% of the 50 mg/L maximumIt passed with room to spare, and everything else tested sat further below its limit. See every reading
  • 4th cleanest of 6 areas tested in Folkestone and HytheSquarely mid-table for Folkestone and Hythe, between CT18 on 9.5 and TN29 on 9.1.
  • Scores higher than 2 of 5 neighbouring districtsWater here is typical for the immediate area, which usually means the same treatment works and the same supply zone.

Next door

CT189.5 out of 10CT199.4 out of 10CT209.4 out of 10TN289.2 out of 10 · 150 mg/LTN299.1 out of 10 · 150 mg/L

Questions about CT21 water

Is CT21 tap water safe to drink?

Based on the latest tests, CT21 (Folkestone and Hythe) water scores 9.4/10, which is safe. 0 of 24 tested contaminants exceeded recommended levels. Water is supplied by Southern Water.

What contaminants are in CT21 water?

We tested 24 contaminants in CT21 water. None exceeded recommended safe levels.

Who supplies water in CT21?

CT21 (Folkestone and Hythe) 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 CT21?

CT21 water scored 9.4/10 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 CT21 water?

No PFAS (forever chemicals) result is attached to the tap-water tests for CT21, 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 CT21?

The Environment Agency rated the Kent South 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 CT21, 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 CT21

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
pH8.27 pHNone
Temperature15.3 °CNone
Conductivity682 µS/cmNone
Nitrate1.5 mg/L50 mg/L
Nitrite0.0042 mg/L0.5 mg/L
Phosphate0.086 mg/LNone
Dissolved Oxygen9.87 mg/LNone
Ammonia0.043 mg/L0.5 mg/L
Zinc0.0089 mg/LNone
Copper0.003 mg/L2 mg/L

Get alerts for your area

We'll email you when water quality data changes for CT21.

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