How Horsham compares
At 153 mg/L (10.7 °Clark), Horsham is 37% below the median of the 411 English towns on this map (243 mg/L). It ranks 291 of 411 for hardness (1 is the hardest).
Water hardness in Horsham
Horsham has moderately hard water: some limescale, but easy to keep on top of.
Data
| Value | 153 mg/L calcium carbonate 10.7 °Clark, 8.6 °dH |
|---|---|
| Band | moderately hard |
| Area | West Sussex |
| Population | 51,472 |
| Water company | Southern Water |
| Postcode checked | RH12 1LR (ZS532) |
| Checked | 21 Oct 2026 |
| From the source | “"waterZoneReference":"ZS532","totalHardness":61.2 (Cal mg/l),"supplySource":"Your water is pumped from underground sources in the greensa"” |
What it means for your home
Moderately hard water leaves some scale, but slowly. The kettle and shower head need descaling now and then, and that is usually all.
The right detergent dose and a correctly set dishwasher are enough for most homes. A softener is rarely needed.
How often to descale
As a rule of thumb for moderately hard water, kettles and shower heads need descaling every six to eight 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 Horsham?
The water company's figure for Horsham is 153 mg/L (10.7 °Clark), which is moderately 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
Crawley 12 km Redhill 23 km Godalming 24 km Portslade 26 km Guildford 26 km Leatherhead 26 km Worthing 27 km Hove 28 km