How Cambridge compares
At 307 mg/L (21.6 °Clark), Cambridge is 26% above the median of the 411 English towns on this map (243 mg/L). It ranks 57 of 411 for hardness (1 is the hardest).
Water hardness in Cambridge
Cambridge has very hard water: limescale builds up quickly, so descale often and protect your boiler.
Data
| Value | 307 mg/L calcium carbonate 21.6 °Clark, 17.2 °dH |
|---|---|
| Band | very hard |
| Area | Cambridgeshire |
| Population | 145,674 |
| Water company | Cambridge Water |
| Postcode checked | CB2 1RT (CAMBRIDGE SOUTH) |
| Checked | 21 Oct 2026 |
| From the source | “"mg/l or ppm CaCO3":"307.2","Degrees Clark":"21.5","Ca":"117.0","Mg":"3.7"” |
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 very 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 Cambridge?
The water company's figure for Cambridge is 307 mg/L (21.6 °Clark), which is very 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
Newmarket 20 km Ely 24 km Huntingdon 25 km Haverhill 26 km Saint Neots 26 km Letchworth Garden City 34 km Bishops Stortford 37 km Hitchin 39 km