Tap water in OL4, OldhamSafe to drink.Soft.
Supplied by United Utilities. 2,938 samples, 16 substances, latest on 30 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
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
BRITA Marella XL + MAXTRA PRO
£25typical price
Basic chlorine and taste improvement on a budget
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What's in a glass of OL4 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.
Trihalomethanes came closest to a limit, at 29% of it. 15 of 16 substances used under a quarter of theirs.
- Trihalomethanes29%
- Nickel11%
- Ammonia11%
- Aluminium6%
- Antimony6%
- Bromate6%
- Lead6%
- Nitrate5%
- Iron3%
- Manganese3%
- Turbidity3%
- Selenium2%
- Nitrite2%
- Cadmium2%
- Chromium2%
- Copper<1%
All 16 results as a table
| Substance | Result | Legal limit | Share of limit |
|---|---|---|---|
| Copper | 0.0000178 mg/L | 2 mg/L | <1% |
| Nickel | 0.00225 mg/L | 0.02 mg/L | 11% |
| Lead | 0.00055 mg/L | 0.01 mg/L | 6% |
| Aluminium | 0.0128 mg/L | 0.2 mg/L | 6% |
| Iron | 0.007 mg/L | 0.2 mg/L | 3% |
| Manganese | 0.00133 mg/L | 0.05 mg/L | 3% |
| Trihalomethanes | 0.0292 mg/L | 0.1 mg/L | 29% |
| Bromate | 0.00061 mg/L | 0.01 mg/L | 6% |
| Turbidity | 0.1 NTU | 4 NTU | 3% |
| Ammonia | 0.054 mg/L | 0.5 mg/L | 11% |
| Nitrate | 2.44 mg/L | 50 mg/L | 5% |
| Nitrite | 0.0098 mg/L | 0.5 mg/L | 2% |
| Cadmium | 0.00009 mg/L | 0.005 mg/L | 2% |
| Chromium | 0.00083 mg/L | 0.05 mg/L | 2% |
| Antimony | 0.00031 mg/L | 0.005 mg/L | 6% |
| Selenium | 0.00085 mg/L | 0.04 mg/L | 2% |
24mg of limescale minerals in every litre
Soft water. Kind to kettles, boilers and skin
You will not need a softener here, and you will use less soap and detergent than most of England.
Your river is the Medlock (Source to Lumb Brook), rated moderate
The Environment Agency rated the Medlock (Source to Lumb Brook) as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. 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
39
forever-chemical detections in nearby rivers and groundwater
At 2 sites. The highest was PFOA at 0.059 µg/L, at Ashton-U-Lyne Golf Club BH SD90/308, 3.8 km away, in September 2024. These are river and borehole samples, not tests of your tap water.
Every PFAS sample around Manchester · Which filters remove PFAS · PFAS explained
OL4 in short
Tap water in OL4 (Oldham) is supplied by United Utilities in the Oldham Central zone and scores 9.4 out of 10, against an England and Wales average of 9.0. None of the 16 tested substances came close to a limit. The latest sample is from 30 December 2024.
- 5th cleanest of 7 areas tested in Oldham2 areas in Oldham scored lower. The best is OL9 on 9.5.
- Soft water at 24 mg/LLimescale is not a problem in OL4, so skip softeners and scale filters entirely. How hardness is measured
- PFAS found at 2 monitoring sites within 10 kmThose are river and groundwater samples, not tap water. The highest was PFOA about 3.8 km away. What was measured
Questions about OL4 water
Is OL4 tap water safe to drink?
Based on the latest tests, OL4 (Oldham) water scores 9.4/10, which is safe. 0 of 16 tested contaminants exceeded recommended levels. Water is supplied by United Utilities.
What contaminants are in OL4 water?
We tested 16 contaminants in OL4 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 OL4?
OL4 (Oldham) is supplied by United Utilities. You can view their full profile and compliance data on our supplier page.
Is OL4 water hard or soft?
Water in OL4 (Oldham) has a hardness of 24 mg/L CaCO3, which is classified as soft. Soft water is gentle on appliances and skin.
Should I use a water filter in OL4?
OL4 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 OL4 water?
The tap-water tests we hold for OL4 do not include a PFAS result. Environment Agency monitoring found PFAS in 39 river and groundwater samples from 2 sites within 10 km of OL4, the highest being PFOA at 0.059 µg/L about 3.8 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 OL4?
The Environment Agency rated the Medlock (Source to Lumb Brook) as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. 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 OL4, 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
- Is UK Tap Water Safe?Everything you need to know about tap water safety in the UK
- Best Water Filters UKEvery filter type compared on what it actually removes
PFAS explainedHow to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map
River and groundwater readings near OL4
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.
| Substance | Reading | Drinking water limit |
|---|---|---|
| pH | 7.61 pH | None |
| Temperature | 15.3 °C | None |
| Conductivity | 79 µS/cm | None |
| Ammonia | 0.093 mg/L | 0.5 mg/L |
| Nitrate | 0.39 mg/L | 50 mg/L |
| Nitrite | 0.0052 mg/L | 0.5 mg/L |
| Phosphate | 0.026 mg/L | None |
| Dissolved Oxygen | 9.83 mg/L | None |
| Hardness (as CaCO3) | 43.8 mg/L | None |
| Copper | 0.00205 mg/L | 2 mg/L |
| Manganese | 0.0253 mg/L | 0.05 mg/L |
| Zinc | 0.00656 mg/L | None |
Get alerts for your area
We'll email you when water quality data changes for OL4.