Tap water in DN4, DoncasterSafe to drink.Very hard.
Supplied by Yorkshire Water. 1,625 samples, 25 substances, latest on 10 September 2026. Everything is inside the legal limit. One result, nitrite, sits close to the line.
8.8 / 10
The tank is as full as the score. The specks are the minerals that make water hard.
What to do about it
Hard water: compare softener quotes
At 258 mg/L a softener is the only thing that stops limescale. Filters do not soften water.
It pays for itself in most homes at this hardness, through a boiler that stays efficient and appliances that last.
Waterdrop G3P600 Reverse Osmosis
£550typical price
Maximum contaminant removal including PFAS and fluoride
Waterdrop 10UA Under Sink
£70typical price
High-volume under-sink filtration without RO complexity
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What's in a glass of DN4 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.
Nitrite came closest to a limit, at 100% of it. 18 of 20 substances used under a quarter of theirs.
- Nitrite100%
- Nitrate50%
- Bromate24%
- Arsenic16%
- Colour15%
- Aluminium6%
- Trihalomethanes6%
- Fluoride5%
- Mercury4%
- Iron3%
- Turbidity3%
- Boron3%
- Manganese2%
- Antimony1%
- Lead1%
- Selenium1%
- Nickel<1%
- Cadmium<1%
- Chromium<1%
- Copper<1%
- E. coli none found
- Coliform Bacteria none found
- Conductivity 494 µS/cm
- Phosphate 0.959 mg/L
All 25 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Nitrite | 0.5 mg/L | 0.5 mg/L | 100% |
| E. coli | 0 count/100ml | Must be zero | None found |
| Coliform Bacteria | 0 count/100ml | Must be zero | None found |
| Nitrate | 25 mg/L | 50 mg/L | 50% |
| Aluminium | 0.0111 mg/L | 0.2 mg/L | 6% |
| Conductivity | 494 µS/cm | No legal limit | – |
| Turbidity | 0.11 NTU | 4 NTU | 3% |
| Colour | 3 mg/L Pt/Co | 20 mg/L Pt/Co | 15% |
| Iron | 0.00629 mg/L | 0.2 mg/L | 3% |
| Manganese | 0.00101 mg/L | 0.05 mg/L | 2% |
| Phosphate | 0.959 mg/L | No legal limit | – |
| Bromate | 0.0024 mg/L | 0.01 mg/L | 24% |
| Trihalomethanes | 0.00554 mg/L | 0.1 mg/L | 6% |
| Mercury | 0.00004 mg/L | 0.001 mg/L | 4% |
| Copper | 0.00337 mg/L | 2 mg/L | <1% |
| Arsenic | 0.00162 mg/L | 0.01 mg/L | 16% |
| Antimony | 0.000064 mg/L | 0.005 mg/L | 1% |
| Selenium | 0.00043 mg/L | 0.04 mg/L | 1% |
| Boron | 0.0251 mg/L | 1 mg/L | 3% |
| Cadmium | 0.000031 mg/L | 0.005 mg/L | <1% |
| Nickel | 0.00017 mg/L | 0.02 mg/L | <1% |
| Chromium | 0.00019 mg/L | 0.05 mg/L | <1% |
| Lead | 0.00011 mg/L | 0.01 mg/L | 1% |
| Fluoride | 0.08 mg/L | 1.5 mg/L | 5% |
| Hardness (as CaCO3) | 255 mg/L | No legal limit | – |
258mg of limescale minerals in every litre
This is the water that furs up kettles
Very hard on the UK scale. It is fine to drink. It is hard on boilers, showers, skin and anything that heats water, and a jug or tap filter will not change that.
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Your river is the Mother Drain from Source to Torne, rated moderate
The Environment Agency rated the Mother Drain from Source to Torne as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by ammonia, dissolved oxygen 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.
None of this is a test of your tap water. Environment Agency record · River health across England
DN4 in short
Tap water in DN4 (Doncaster) is supplied by Yorkshire Water in the Doncaster Central zone and scores 8.8 out of 10, against an England and Wales average of 9.0. 1 of 25 tested substances was close to or over a limit. The latest sample is from 10 September 2026.
- Nitrite is within its legal limit but flagged, at 100% of the 0.5 mg/L maximumAnything over three quarters of a limit is flagged here as worth watching. It has not gone over. See every reading
- 9th cleanest of 10 areas tested in Doncaster1 area in Doncaster scored lower. The best is DN6 on 9.3.
- Very hard water at 258 mg/LThe threshold for very hard is 250 mg/L. Expect visible limescale on taps and in kettles in DN4. How hardness is measured
Questions about DN4 water
Is DN4 tap water safe to drink?
Based on the latest tests, DN4 (Doncaster) water scores 8.8/10, which is safe. 1 of 25 tested contaminants exceeded recommended levels. Water is supplied by Yorkshire Water.
What contaminants are in DN4 water?
We tested 25 contaminants in DN4 water. 1 were flagged, including Nitrite.
Who supplies water in DN4?
DN4 (Doncaster) is supplied by Yorkshire Water. You can view their full profile and compliance data on our supplier page.
Is DN4 water hard or soft?
Water in DN4 (Doncaster) has a hardness of 258 mg/L CaCO3, which is classified as very hard. Hard water can cause limescale buildup. A water softener or filter jug may help.
Should I use a water filter in DN4?
With 1 contaminant above recommended levels in DN4, a water filter could help. A filter jug or under-sink filter can reduce most common contaminants. See our filter recommendations for your area.
Are there PFAS forever chemicals in DN4 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for DN4, 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 DN4?
The Environment Agency rated the Mother Drain from Source to Torne as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by ammonia, dissolved oxygen 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. This is a rating of the river, not of tap water in DN4, which is treated before it reaches homes.
Keep reading
- Best Water Softener UKHarvey, Kinetico, BWT, Monarch and Water2Buy compared, with real costs
- Do I Need a Water Softener?The hardness bands, the symptoms, and a postcode check
- UK Water Hardness MapIs your water hard or soft, and does it matter?
- Best Water Filters UKEvery filter type compared on what it actually removes
- Do I need a water softener?The hardness bands, the symptoms, and when the answer is no
- Best water softener UKHarvey, Kinetico, BWT, Monarch and Water2Buy compared
- Water softener costUnit, fitting and salt, and how long the payback takes
- Installation explainedWhere it goes, the bypass tap, the drain, DIY or plumber
- Harvey vs KineticoThe two premium twin-cylinder brands, side by side
- Softener salt guideTablet, block or granular, and how much you get through
- Salt-free softenersConditioners and electronic descalers, honestly assessed
Nitrate levelsHow to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map
River and groundwater readings near DN4
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.
Get alerts for your area
We'll email you when water quality data changes for DN4.