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tapwater
England and Wales average 9.0

Tap water in DE21, DerbySafe to drink.

Supplied by Severn Trent. 1,480 samples, 20 substances, latest on 19 December 2025. Everything is inside the legal limit, and nothing comes close to it.

See the filter we recommendSee everything that was tested

9.2 / 10

The tank is as full as the score.

What to do about it

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Households concerned about PFAS and heavy metals

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High-volume under-sink filtration without RO complexity

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Basic chlorine and taste improvement on a budget

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What's in a glass of DE21 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.

Trihalomethanes came closest to a limit, at 49% of it. 16 of 17 substances used under a quarter of theirs.

0%25%50%75%limitLegal limitNitrite: 0.003 mg/L, <1% of the 0.5 mg/L limitNitrite<1%Copper: 0.0131 mg/L, <1% of the 2 mg/L limitCopper<1%Chromium: 0.00042 mg/L, <1% of the 0.05 mg/L limitChromium<1%Selenium: 0.00041 mg/L, 1% of the 0.04 mg/L limitSelenium1%Arsenic: 0.00014 mg/L, 1% of the 0.01 mg/L limitArsenic1%Antimony: 0.000084 mg/L, 2% of the 0.005 mg/L limitAntimony2%Manganese: 0.0011 mg/L, 2% of the 0.05 mg/L limitManganese2%Turbidity: 0.12 NTU, 3% of the 4 NTU limitTurbidity3%Lead: 0.00038 mg/L, 4% of the 0.01 mg/L limitLead4%Colour: 0.8 mg/L Pt/Co, 4% of the 20 mg/L Pt/Co limitColour4%Cadmium: 0.0002 mg/L, 4% of the 0.005 mg/L limitCadmium4%Aluminium: 0.021 mg/L, 11% of the 0.2 mg/L limitAluminium11%Nitrate: 5.8 mg/L, 12% of the 50 mg/L limitNitrate12%Fluoride: 0.19 mg/L, 13% of the 1.5 mg/L limitFluoride13%Nickel: 0.0027 mg/L, 14% of the 0.02 mg/L limitNickel14%Iron: 0.0324 mg/L, 16% of the 0.2 mg/L limitIron16%Trihalomethanes: 0.049 mg/L, 49% of the 0.1 mg/L limitTrihalomethanes49%
  1. Trihalomethanes49%
  2. Iron16%
  3. Nickel14%
  4. Fluoride13%
  5. Nitrate12%
  6. Aluminium11%
  7. Colour4%
  8. Cadmium4%
  9. Lead4%
  10. Turbidity3%
  11. Manganese2%
  12. Antimony2%
  13. Arsenic1%
  14. Selenium1%
  15. Chromium<1%
  16. Copper<1%
  17. Nitrite<1%
  • Conductivity 401 µS/cm
  • pH 7.56 pH
  • Phosphate 0.974 mg/L
All 20 results as a table
SubstanceResultLegal limitShare of limit
Conductivity401 µS/cmNo legal limit–
pH7.56 pHNo legal limit–
Colour0.8 mg/L Pt/Co20 mg/L Pt/Co
4%
Turbidity0.12 NTU4 NTU
3%
Aluminium0.021 mg/L0.2 mg/L
11%
Iron0.0324 mg/L0.2 mg/L
16%
Manganese0.0011 mg/L0.05 mg/L
2%
Trihalomethanes0.049 mg/L0.1 mg/L
49%
Nitrate5.8 mg/L50 mg/L
12%
Nitrite0.003 mg/L0.5 mg/L
<1%
Copper0.0131 mg/L2 mg/L
<1%
Fluoride0.19 mg/L1.5 mg/L
13%
Arsenic0.00014 mg/L0.01 mg/L
1%
Cadmium0.0002 mg/L0.005 mg/L
4%
Chromium0.00042 mg/L0.05 mg/L
<1%
Nickel0.0027 mg/L0.02 mg/L
14%
Lead0.00038 mg/L0.01 mg/L
4%
Antimony0.000084 mg/L0.005 mg/L
2%
Selenium0.00041 mg/L0.04 mg/L
1%
Phosphate0.974 mg/LNo legal limit–
Outside your tap

Your river is the Chaddesden Brook Catchment (trib of Derwent), rated moderate

The Environment Agency rated the Chaddesden Brook Catchment (trib of Derwent) as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by 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

Within 10 km

186

forever-chemical detections in nearby rivers and groundwater

At 17 sites. The highest was 6:2 FTSA at 0.061 µg/L, at Spring at Breadsall Manor Groundwater Quality Monitoring D22/15A, 3.1 km away, in March 2026. These are river and borehole samples, not tests of your tap water.

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

DE21 in short

Tap water in DE21 (Derby) is supplied by Severn Trent in the Derby Central zone and scores 9.2 out of 10, against an England and Wales average of 9.0. None of the 20 tested substances came close to a limit. The latest sample is from 19 December 2025.

  • Trihalomethanes is the reading closest to its limit, at 49% of the 0.1 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 DerbySquarely mid-table for Derby, between DE1 on 9.3 and DE3 on 8.6. Every area in Derby
  • PFAS found at 17 monitoring sites within 10 kmThose are river and groundwater samples, not tap water. The highest was 6:2 FTSA about 3.1 km away. What was measured

Next door

DE229.3 out of 10DE19.3 out of 10DE239.2 out of 10DE249.3 out of 10DE38.6 out of 10

Questions about DE21 water

Is DE21 tap water safe to drink?

Based on the latest tests, DE21 (Derby) water scores 9.2/10, which is safe. 0 of 20 tested contaminants exceeded recommended levels. Water is supplied by Severn Trent.

What contaminants are in DE21 water?

We tested 20 contaminants in DE21 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 DE21?

DE21 (Derby) is supplied by Severn Trent. You can view their full profile and compliance data on our supplier page.

Should I use a water filter in DE21?

DE21 water scored 9.2/10 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 DE21 water?

The tap-water tests we hold for DE21 do not include a PFAS result. Environment Agency monitoring found PFAS in 186 river and groundwater samples from 17 sites within 10 km of DE21, the highest being 6:2 FTSA at 0.061 µg/L about 3.1 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 river near DE21?

The Environment Agency rated the Chaddesden Brook Catchment (trib of Derwent) as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by 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 DE21, which is treated before it reaches homes.

Keep reading

PFAS explainedHow to test your waterBest water filtersFilter shower headsWater testing kitsAll of DerbyUK water rankingsWater hardness checkerWater hardness map

River and groundwater readings near DE21

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
Manganese0.066 mg/L0.05 mg/L
Lead0.0055 mg/L0.01 mg/L
pH7.9 pHNone
Temperature16.2 °CNone
Conductivity672 µS/cmNone
Cadmium0.00016 mg/L0.005 mg/L
Hardness (as CaCO3)234 mg/LNone
Zinc0.028 mg/LNone
Nickel0.0022 mg/L0.02 mg/L
Copper0.0012 mg/L2 mg/L
Iron0.051 mg/L0.2 mg/L
Ammonia0.048 mg/L0.5 mg/L
Nitrate2.6 mg/L50 mg/L

Get alerts for your area

We'll email you when water quality data changes for DE21.

Source: Severn Trent 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