Tap water in CB11, UttlesfordToo few tap tests to call it.Very hard.
Supplied by Anglian Water. 10 substances, latest on 1 September 2026. These are river and groundwater samples near CB11, not tests of treated tap water, so treat the score as a rough guide.
6.6 / 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 333 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.
Osmio PRO-III Ultimate Whole House
£499typical price
Removes turbidity, the result that stood out in CB11.
BWT E1 Single Lever
£250typical price
Removes turbidity, the result that stood out in CB11.
We earn a commission if you buy through these links, at no extra cost to you. It never changes which product we put first. How we make money
What's in a glass of CB11 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.
Iron came closest to a limit, at 100% of it. 2 of 5 substances used under a quarter of theirs.
- Iron100%
- Turbidity88%
- Nitrate26%
- Ammonia11%
- Nitrite7%
- pH 7.81 pH
- Temperature 16.3 °C
- Conductivity 959 µS/cm
- Phosphate 0.93 mg/L
- Dissolved Oxygen 7.68 mg/L
All 10 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Iron | 0.2 mg/L | 0.2 mg/L | 100% |
| Turbidity | 3.5 NTU | 4 NTU | 88% |
| pH | 7.81 pH | No legal limit | – |
| Temperature | 16.3 °C | No legal limit | – |
| Conductivity | 959 µS/cm | No legal limit | – |
| Nitrate | 13 mg/L | 50 mg/L | 26% |
| Nitrite | 0.034 mg/L | 0.5 mg/L | 7% |
| Phosphate | 0.93 mg/L | No legal limit | – |
| Dissolved Oxygen | 7.68 mg/L | No legal limit | – |
| Ammonia | 0.056 mg/L | 0.5 mg/L | 11% |
333mg 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.
Softener quotes for CB11
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Your river is the Cam (Newport to Audley End), rated moderate
The Environment Agency rated the Cam (Newport to Audley End) 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 and dissolved oxygen. 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
CB11 in short
Tap water in CB11 (Uttlesford) is supplied by Anglian Water in the Uttlesford Central zone and scores 6.6 out of 10, against an England and Wales average of 9.0. 2 of 10 tested substances were close to or over a limit. The latest sample is from 1 September 2026.
- Iron is within its legal limit but flagged, at 100% of the 0.2 mg/L maximumAnything over three quarters of a limit is flagged here as worth watching. It has not gone over. See every reading
- The lowest score of the 5 areas tested in UttlesfordCB11 scores 6.6 out of 10. The best in Uttlesford, CB10, scores 9.7.
- Among the hardest water in the country at 333 mg/LVery hard starts at 250 mg/L. At this level kettles scale up within weeks and a softener is a normal purchase in CB11. How hardness is measured
Questions about CB11 water
Is CB11 tap water safe to drink?
Based on the latest tests, CB11 (Uttlesford) water scores 6.6/10, which is mostly safe but has some issues. 2 of 10 tested contaminants exceeded recommended levels. Water is supplied by Anglian Water.
What contaminants are in CB11 water?
We tested 10 contaminants in CB11 water. 2 were flagged, including Iron, Turbidity.
Who supplies water in CB11?
CB11 (Uttlesford) is supplied by Anglian Water. You can view their full profile and compliance data on our supplier page.
Is CB11 water hard or soft?
Water in CB11 (Uttlesford) has a hardness of 333 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 CB11?
With 2 contaminants above recommended levels in CB11, 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 CB11 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for CB11, 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 CB11?
The Environment Agency rated the Cam (Newport to Audley End) 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 and dissolved oxygen. 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 CB11, which is treated before it reaches homes.
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