Tap water in CO12, Tendring4 results are over the limit.Very hard.
Supplied by Anglian Water. 14 substances, latest on 17 July 2026. Ammonia, Fluoride and Iron came in above the legal limit. Everything else passed.
4.4 / 10
The tank is as full as the score. The specks are the minerals that make water hard.
What to do about it
Waterdrop G3P600 Reverse Osmosis
£550typical price
Removes fluoride, the result that stood out in CO12.
Stop the limescale
At 312 mg/L a softener is the only thing that stops limescale. Filters do not soften water.
ZeroWater 12-Cup Ready-Pour
£40typical price
Removes fluoride, the result that stood out in CO12.
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What's in a glass of CO12 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 is over its legal limit, at 2950% of it.
- Iron2950%
- Ammonia400%
- Boron180%
- Fluoride153%
- Manganese74%
- Nickel13%
- Lead<1%
- Copper<1%
- pH 7.95 pH
- Temperature 15.3 °C
- Conductivity 5627 µS/cm
- Zinc 0.0093 mg/L
- Dissolved Oxygen 3.87 mg/L
All 14 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Ammonia | 2 mg/L | 0.5 mg/L | 400% |
| Fluoride | 2.3 mg/L | 1.5 mg/L | 153% |
| Iron | 5.9 mg/L | 0.2 mg/L | 2950% |
| Boron | 1.8 mg/L | 1 mg/L | 180% |
| pH | 7.95 pH | No legal limit | – |
| Temperature | 15.3 °C | No legal limit | – |
| Conductivity | 5627 µS/cm | No legal limit | – |
| Hardness (as CaCO3) | 397 mg/L | No legal limit | – |
| Lead | 0.00005 mg/L | 0.01 mg/L | <1% |
| Zinc | 0.0093 mg/L | No legal limit | – |
| Nickel | 0.0026 mg/L | 0.02 mg/L | 13% |
| Manganese | 0.037 mg/L | 0.05 mg/L | 74% |
| Copper | 0.00002 mg/L | 2 mg/L | <1% |
| Dissolved Oxygen | 3.87 mg/L | No legal limit | – |
312mg 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 Ramsey River, rated moderate
The Environment Agency rated the Ramsey River as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by dissolved oxygen, phosphate and insects and other small river life. 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
19
forever-chemical detections in nearby rivers and groundwater
At 2 sites. The highest was PFBS at 0.011 µg/L, at Long Wood Spring, Pinmill, Chelmondiston, 7.9 km away, in October 2024. These are river and borehole samples, not tests of your tap water.
Every PFAS sample around Ipswich · Which filters remove PFAS · PFAS explained
CO12 in short
Tap water in CO12 (Tendring) is supplied by Anglian Water in the Tendring Central zone and scores 4.4 out of 10, against an England and Wales average of 9.0. 4 of 14 tested substances were close to or over a limit. The latest sample is from 17 July 2026.
- Iron was measured at 5.9 mg/L, 30 times the UK limitIt is the furthest over its limit of the 4 substances flagged here. See the full results
- Among the hardest water in the country at 312 mg/LVery hard starts at 250 mg/L. At this level kettles scale up within weeks and a softener is a normal purchase in CO12. How hardness is measured
- 4.6 points below the national average of 9Below the typical tested district in the UK, which is worth knowing before you choose a filter. Compare every area
Questions about CO12 water
Is CO12 tap water safe to drink?
Based on the latest tests, CO12 (Tendring) water scores 4.4/10, which is mostly safe but has some issues. 4 of 14 tested contaminants exceeded recommended levels. Water is supplied by Anglian Water.
What contaminants are in CO12 water?
We tested 14 contaminants in CO12 water. 4 were flagged, including Ammonia, Fluoride, Iron. 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 CO12?
CO12 (Tendring) is supplied by Anglian Water. You can view their full profile and compliance data on our supplier page.
Is CO12 water hard or soft?
Water in CO12 (Tendring) has a hardness of 312 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 CO12?
With 4 contaminants above recommended levels in CO12, a water filter could help. A reverse osmosis or activated carbon filter is recommended for PFAS removal. See our filter recommendations for your area.
Are there PFAS forever chemicals in CO12 water?
The tap-water tests we hold for CO12 do not include a PFAS result. Environment Agency monitoring found PFAS in 19 river and groundwater samples from 2 sites within 10 km of CO12, the highest being PFBS at 0.011 µg/L about 7.9 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 CO12?
The Environment Agency rated the Ramsey River as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by dissolved oxygen, phosphate and insects and other small river life. 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 CO12, 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
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- 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
PFAS explainedHow to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map
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