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tapwater
England and Wales average 9.0

Tap water in DL4, County DurhamSafe to drink.Moderately soft.

Supplied by Northumbrian Water. 1,757 samples, 20 substances, latest on 9 December 2025. Everything is inside the legal limit, and nothing comes close to it.

See the filter we recommendSee everything that was tested

9.6 / 10

The tank is as full as the score. The specks are the minerals that make water hard.

What to do about it

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Basic chlorine and taste improvement on a budget

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What's in a glass of DL4 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.

Aluminium came closest to a limit, at 18% of it. 18 of 18 substances used under a quarter of theirs.

0%25%50%75%limitLegal limitCadmium: 0.000018 mg/L, <1% of the 0.005 mg/L limitCadmium<1%Boron: 0.0064 mg/L, <1% of the 1 mg/L limitBoron<1%Arsenic: 0.00007 mg/L, <1% of the 0.01 mg/L limitArsenic<1%Nitrite: 0.0061 mg/L, 1% of the 0.5 mg/L limitNitrite1%Chromium: 0.00067 mg/L, 1% of the 0.05 mg/L limitChromium1%Copper: 0.031 mg/L, 2% of the 2 mg/L limitCopper2%Selenium: 0.00083 mg/L, 2% of the 0.04 mg/L limitSelenium2%Lead: 0.00021 mg/L, 2% of the 0.01 mg/L limitLead2%Nitrate: 1.5 mg/L, 3% of the 50 mg/L limitNitrate3%Antimony: 0.00016 mg/L, 3% of the 0.005 mg/L limitAntimony3%Manganese: 0.0017 mg/L, 3% of the 0.05 mg/L limitManganese3%Turbidity: 0.2 NTU, 5% of the 4 NTU limitTurbidity5%Bromate: 0.0005 mg/L, 5% of the 0.01 mg/L limitBromate5%Nickel: 0.0011 mg/L, 6% of the 0.02 mg/L limitNickel6%Colour: 1.2 mg/L Pt/Co, 6% of the 20 mg/L Pt/Co limitColour6%Fluoride: 0.17 mg/L, 11% of the 1.5 mg/L limitFluoride11%Iron: 0.029 mg/L, 14% of the 0.2 mg/L limitIron14%Aluminium: 0.036 mg/L, 18% of the 0.2 mg/L limitAluminium18%
  1. Aluminium18%
  2. Iron14%
  3. Fluoride11%
  4. Colour6%
  5. Nickel6%
  6. Turbidity5%
  7. Bromate5%
  8. Manganese3%
  9. Antimony3%
  10. Nitrate3%
  11. Lead2%
  12. Selenium2%
  13. Copper2%
  14. Chromium1%
  15. Nitrite1%
  16. Arsenic<1%
  17. Boron<1%
  18. Cadmium<1%
  • pH 7.1 pH
  • Conductivity 150 µS/cm
All 20 results as a table
SubstanceResultLegal limitShare of limit
Aluminium0.036 mg/L0.2 mg/L
18%
Colour1.2 mg/L Pt/Co20 mg/L Pt/Co
6%
Manganese0.0017 mg/L0.05 mg/L
3%
pH7.1 pHNo legal limit–
Turbidity0.2 NTU4 NTU
5%
Conductivity150 µS/cmNo legal limit–
Iron0.029 mg/L0.2 mg/L
14%
Boron0.0064 mg/L1 mg/L
<1%
Nitrate1.5 mg/L50 mg/L
3%
Lead0.00021 mg/L0.01 mg/L
2%
Bromate0.0005 mg/L0.01 mg/L
5%
Nickel0.0011 mg/L0.02 mg/L
6%
Nitrite0.0061 mg/L0.5 mg/L
1%
Arsenic0.00007 mg/L0.01 mg/L
<1%
Antimony0.00016 mg/L0.005 mg/L
3%
Cadmium0.000018 mg/L0.005 mg/L
<1%
Copper0.031 mg/L2 mg/L
2%
Fluoride0.17 mg/L1.5 mg/L
11%
Selenium0.00083 mg/L0.04 mg/L
2%
Chromium0.00067 mg/L0.05 mg/L
1%

115mg of limescale minerals in every litre

Soft water. Kind to kettles, boilers and skin

You will not need a softener here, and you will use less soap and detergent than most of England.

Soft400 mg/L
Outside your tap

Your river is the Woodham Burn from Source to Rushyford beck, rated moderate

The Environment Agency rated the Woodham Burn from Source to Rushyford beck as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by insects and other small river life, 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. Its ecological rating has improved since the previous assessment.

None of this is a test of your tap water. Environment Agency record · River health across England

DL4 in short

Tap water in DL4 (County Durham) is supplied by Northumbrian Water in the County Durham Central zone and scores 9.6 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 9 December 2025.

  • 10th cleanest of 22 areas tested in County DurhamSquarely mid-table for County Durham, between DH1 on 9.7 and TS28 on 9.
  • 0.6 points above the national average of 9Cleaner than the typical tested district in the UK. Compare every area
  • Nothing tested came within 40% of its legal limitThe highest was Aluminium at 18% of the 0.2 mg/L maximum. See every reading

Next door

DH79.4 out of 10 · 85 mg/LDH19.7 out of 10 · 68 mg/LDH39.4 out of 10 · 80 mg/LDH99.5 out of 10 · 78 mg/LDL59.7 out of 10 · 115 mg/LDL149.6 out of 10 · 115 mg/LDL169.4 out of 10 · 70 mg/LDH29.4 out of 10 · 80 mg/LDL179.7 out of 10 · 70 mg/LDL139.7 out of 10 · 85 mg/L

Questions about DL4 water

Is DL4 tap water safe to drink?

Based on the latest tests, DL4 (County Durham) water scores 9.6/10, which is safe. 0 of 20 tested contaminants exceeded recommended levels. Water is supplied by Northumbrian Water.

What contaminants are in DL4 water?

We tested 20 contaminants in DL4 water. None exceeded recommended safe levels.

Who supplies water in DL4?

DL4 (County Durham) is supplied by Northumbrian Water. You can view their full profile and compliance data on our supplier page.

Is DL4 water hard or soft?

Water in DL4 (County Durham) has a hardness of 115 mg/L CaCO3, which is classified as moderately soft. This is a moderate hardness level.

Should I use a water filter in DL4?

DL4 water scored 9.6/10 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 DL4 water?

No PFAS (forever chemicals) result is attached to the tap-water tests for DL4, 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 DL4?

The Environment Agency rated the Woodham Burn from Source to Rushyford beck as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by insects and other small river life, 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. Its ecological rating has improved since the previous assessment. This is a rating of the river, not of tap water in DL4, 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 DL4

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
Iron1.3 mg/L0.2 mg/L
pH7.99 pHNone
Temperature16.5 °CNone
Conductivity343 µS/cmNone
Ammonia0.021 mg/L0.5 mg/L
Nitrate0.86 mg/L50 mg/L
Nitrite0.013 mg/L0.5 mg/L
Phosphate0.03 mg/LNone
Dissolved Oxygen9.65 mg/LNone
Aluminium0.0259 mg/L0.2 mg/L

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We'll email you when water quality data changes for DL4.

Source: Northumbrian 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