Tap water in NN11, West NorthamptonshireSafe to drink.Hard.
Supplied by Anglian Water. 1,044 samples, 19 substances, latest on 23 December 2024. Everything is inside the legal limit, and nothing comes close to it.
9.4 / 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 186 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.
ZeroWater 12-Cup Ready-Pour
£40typical price
Households concerned about PFAS and heavy metals
Waterdrop 10UA Under Sink
£70typical price
High-volume under-sink filtration without RO complexity
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What's in a glass of NN11 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 27% of it. 15 of 16 substances used under a quarter of theirs.
- Nitrate27%
- Fluoride19%
- Trihalomethanes15%
- Iron11%
- Nitrite8%
- Nickel8%
- Aluminium6%
- Manganese6%
- Turbidity5%
- Lead5%
- Antimony4%
- Arsenic3%
- Selenium2%
- Chromium2%
- Copper2%
- Cadmium<1%
- Conductivity 458 µS/cm
- Coliform Bacteria none found
- E. coli none found
All 19 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Conductivity | 458 µS/cm | No legal limit | – |
| Turbidity | 0.21 NTU | 4 NTU | 5% |
| Nitrate | 13.4 mg/L | 50 mg/L | 27% |
| Nitrite | 0.04 mg/L | 0.5 mg/L | 8% |
| Aluminium | 0.012 mg/L | 0.2 mg/L | 6% |
| Iron | 0.021 mg/L | 0.2 mg/L | 11% |
| Manganese | 0.003 mg/L | 0.05 mg/L | 6% |
| Coliform Bacteria | 0 count/100ml | Must be zero | None found |
| E. coli | 0 count/100ml | Must be zero | None found |
| Trihalomethanes | 0.0153 mg/L | 0.1 mg/L | 15% |
| Copper | 0.03 mg/L | 2 mg/L | 2% |
| Fluoride | 0.29 mg/L | 1.5 mg/L | 19% |
| Arsenic | 0.00028 mg/L | 0.01 mg/L | 3% |
| Cadmium | 0.00002 mg/L | 0.005 mg/L | <1% |
| Chromium | 0.00076 mg/L | 0.05 mg/L | 2% |
| Nickel | 0.00151 mg/L | 0.02 mg/L | 8% |
| Lead | 0.00051 mg/L | 0.01 mg/L | 5% |
| Antimony | 0.00021 mg/L | 0.005 mg/L | 4% |
| Selenium | 0.00072 mg/L | 0.04 mg/L | 2% |
186mg of limescale minerals in every litre
This is the water that furs up kettles
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.
Softener quotes for NN11
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Your river is the Nene - headwaters to conf Whilton Branch, rated poor
The Environment Agency rated the Nene - headwaters to conf Whilton Branch as poor for ecological health in its 2025 assessment, meaning the river is badly affected, with much of the expected wildlife missing. It is held back by water plants and algae. 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
59
forever-chemical detections in nearby rivers and groundwater
At 3 sites. The highest was 6:2 FTSA at 0.019 µg/L, at Whilton Branch of Nene Weedon A45 Rd.br., 7.2 km away, in August 2025. These are river and borehole samples, not tests of your tap water.
Every PFAS sample around Northampton · Which filters remove PFAS · PFAS explained
NN11 in short
Tap water in NN11 (West Northamptonshire) is supplied by Anglian Water in the West Northamptonshire Central zone and scores 9.4 out of 10, against an England and Wales average of 9.0. None of the 19 tested substances came close to a limit. The latest sample is from 23 December 2024.
- The cleanest tap water of the 12 areas tested in NorthamptonNN11 scores 9.4 out of 10, ahead of NN2 in second place on 9.4. Every area in Northampton
- Hard water at 186 mg/LHard starts at 180 mg/L, the point where a softener begins to pay for itself. Limescale will build up in NN11. How hardness is measured
- PFAS found at 3 monitoring sites within 10 kmThose are river and groundwater samples, not tap water. The highest was 6:2 FTSA about 7.2 km away. What was measured
Questions about NN11 water
Is NN11 tap water safe to drink?
Based on the latest tests, NN11 (West Northamptonshire) water scores 9.4/10, which is safe. 0 of 19 tested contaminants exceeded recommended levels. Water is supplied by Anglian Water.
What contaminants are in NN11 water?
We tested 19 contaminants in NN11 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 NN11?
NN11 (West Northamptonshire) is supplied by Anglian Water. You can view their full profile and compliance data on our supplier page.
Is NN11 water hard or soft?
Water in NN11 (West Northamptonshire) has a hardness of 186 mg/L CaCO3, which is classified as hard. Hard water can cause limescale buildup. A water softener or filter jug may help.
Should I use a water filter in NN11?
NN11 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 NN11 water?
The tap-water tests we hold for NN11 do not include a PFAS result. Environment Agency monitoring found PFAS in 59 river and groundwater samples from 3 sites within 10 km of NN11, the highest being 6:2 FTSA at 0.019 µg/L about 7.2 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 NN11?
The Environment Agency rated the Nene - headwaters to conf Whilton Branch as poor for ecological health in its 2025 assessment, meaning the river is badly affected, with much of the expected wildlife missing. It is held back by water plants and algae. 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 NN11, which is treated before it reaches homes.
Keep reading
- Best Filter for PFAS RemovalThe filters with independent certification to remove forever chemicals
- PFAS Forever ChemicalsWhat PFAS are and how to reduce your exposure at home
- 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?
- 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
PFAS explainedHow to test your waterBest water filtersFilter shower headsWater testing kitsAll of NorthamptonUK water rankingsWater hardness checkerWater hardness map
River and groundwater readings near NN11
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 NN11.