Tap water in GL18, Forest of DeanSafe to drink.Very hard.
Supplied by Severn Trent. 533 samples, 20 substances, latest on 20 December 2025. Everything is inside the legal limit. One result, nitrate, sits close to the line.
9.0 / 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
Removes nitrate, the result that stood out in GL18.
Osmio PRO-III Ultimate Whole House
£499typical price
Removes nitrate, the result that stood out in GL18.
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 GL18 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 82% of it. 16 of 17 substances used under a quarter of theirs.
- Nitrate82%
- Aluminium11%
- Lead10%
- Copper9%
- Fluoride8%
- Arsenic8%
- Selenium6%
- Nickel6%
- Trihalomethanes5%
- Colour4%
- Iron3%
- Turbidity3%
- Manganese1%
- Antimony1%
- Chromium<1%
- Nitrite<1%
- Cadmium<1%
- pH 7.31 pH
- Conductivity 624 µS/cm
- Phosphate 0.643 mg/L
All 20 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Nitrate | 41.2 mg/L | 50 mg/L | 82% |
| pH | 7.31 pH | No legal limit | – |
| Nitrite | 0.003 mg/L | 0.5 mg/L | <1% |
| Aluminium | 0.021 mg/L | 0.2 mg/L | 11% |
| Iron | 0.007 mg/L | 0.2 mg/L | 3% |
| Manganese | 0.00073 mg/L | 0.05 mg/L | 1% |
| Copper | 0.173 mg/L | 2 mg/L | 9% |
| Fluoride | 0.12 mg/L | 1.5 mg/L | 8% |
| Arsenic | 0.00079 mg/L | 0.01 mg/L | 8% |
| Cadmium | 0.00002 mg/L | 0.005 mg/L | <1% |
| Chromium | 0.00042 mg/L | 0.05 mg/L | <1% |
| Nickel | 0.0012 mg/L | 0.02 mg/L | 6% |
| Lead | 0.00096 mg/L | 0.01 mg/L | 10% |
| Antimony | 0.000059 mg/L | 0.005 mg/L | 1% |
| Selenium | 0.00241 mg/L | 0.04 mg/L | 6% |
| Conductivity | 624 µS/cm | No legal limit | – |
| Trihalomethanes | 0.0049 mg/L | 0.1 mg/L | 5% |
| Colour | 0.8 mg/L Pt/Co | 20 mg/L Pt/Co | 4% |
| Turbidity | 0.12 NTU | 4 NTU | 3% |
| Phosphate | 0.643 mg/L | No legal limit | – |
258mg of limescale minerals in every litre, typical for the GL area. GL18 has no reading of its own.
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 GL18
Leave your details and we will email you when we can match you with installers who cover GL18. No obligation.
Request a free assessment and we'll come back to you with local installer options for your area.
100%
free, no obligation
shared only with your consent
Your river is the Ell Bk - source to conf R Leadon, rated moderate
The Environment Agency rated the Ell Bk - source to conf R Leadon 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. 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
GL18 in short
Tap water in GL18 (Forest of Dean) is supplied by Severn Trent in the Forest of Dean Central zone and scores 9.0 out of 10, against an England and Wales average of 9.0. 1 of 20 tested substances was close to or over a limit. The latest sample is from 20 December 2025.
- Nitrate is within its legal limit but flagged, at 82% of the 50 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 6 areas tested in Forest of DeanGL18 scores 9 out of 10. The best in Forest of Dean, GL14, scores 9.6.
- Every one of the 5 neighbouring districts scores higherGL14 next door scores 9.6, against 9 here. Supply zones, not distance, explain the gap. See GL14
Questions about GL18 water
Is GL18 tap water safe to drink?
Based on the latest tests, GL18 (Forest of Dean) water scores 9/10, which is safe. 1 of 20 tested contaminants exceeded recommended levels. Water is supplied by Severn Trent.
What contaminants are in GL18 water?
We tested 20 contaminants in GL18 water. 1 were flagged, including Nitrate.
Who supplies water in GL18?
GL18 (Forest of Dean) is supplied by Severn Trent. You can view their full profile and compliance data on our supplier page.
Is GL18 water hard or soft?
No hardness reading has been published for GL18 itself. Across the GL postcode area the typical value is 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 GL18?
With 1 contaminant above recommended levels in GL18, 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 GL18 water?
No PFAS (forever chemicals) result is attached to the tap-water tests for GL18, 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 GL18?
The Environment Agency rated the Ell Bk - source to conf R Leadon 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. 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 GL18, 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 GL18
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 GL18.