How Oxford compares
At 258 mg/L (18.1 °Clark), Oxford is 6% above the median of the 411 English towns on this map (243 mg/L). It ranks 178 of 411 for hardness (1 is the hardest).
Water hardness in Oxford
Oxford has hard water: expect visible limescale and plan to descale regularly.
Data
| Value | 258 mg/L calcium carbonate 18.1 °Clark, 14.5 °dH |
|---|---|
| Band | hard |
| Area | Oxfordshire |
| Population | 162,100 |
| Water company | Thames Water |
| Postcode checked | OX1 4AG (OX13) |
| Checked | 21 Oct 2026 |
| From the source | “Hardness (Total) as CaCO3 (mg/l) min 239 mean 258 max 278 | "mapCode":"OX13"” |
What it means for your home
Hard water drops a lot of scale when it is heated: in the kettle, the shower head and the element of an immersion heater or washing machine. Chalky rings on taps and spotty glasses are normal.
Set the dishwasher for hard water, dose detergent for your band and descale regularly. If you have a combi boiler, ask about a scale reducer at its next service. Hard water is safe to drink.
How often to descale
As a rule of thumb for hard water, kettles and shower heads need descaling every three or four weeks. Descale whenever you see scale building up.
Common questions
Is hard water bad for you?
No. Hard water carries calcium and magnesium, minerals the body uses. Whether tap water is safe depends on germs and pollutants, which water companies test for, not on hardness.
Do I need a water softener in Oxford?
The water company's figure for Oxford is 258 mg/L (18.1 °Clark), which is hard water. Usually not straight away. Set the dishwasher, dose detergent for your band and descale regularly. Get quotes for a softener only if scale is clearly damaging your boiler or appliances.
How do I find the value for my address?
Use your water company's postcode checker. Hardness can differ between districts, so check your own postcode, or test with strips or a drop test.
Nearby towns
Abingdon 9 km Didcot 16 km Witney 16 km Bicester 18 km Aylesbury 31 km Banbury 35 km High Wycombe 38 km Reading 38 km