UK region

Water hardness in South East

Average 274 ppm across 352 postcode districts — classified as hard.

  • Range 163–350 ppm
  • Counties 8
  • Suppliers Affinity Water, Anglian Water, Portsmouth Water, Severn Trent Water, Southern Water, Thames Water
Regional average
274
ppm CaCO₃
Hard
Soft
Moderate
Hard
Very hard
0100200300400+
274
Avg ppm
163
Min ppm
350
Max ppm
352
Postcodes

Water Hardness Across South East

The average water hardness in the South East region is 274 ppm, classified as hard. Across 352 postcode districts, hardness ranges from 163 ppm to 350 ppm.

The region is served by Affinity Water, Anglian Water, Portsmouth Water, Severn Trent Water, Southern Water, Thames Water. Water hardness varies by county — see the breakdown below or check your specific postcode.

By county

Counties in South East

Sorted by hardness — see how your county compares.

County Hardness PPM Level Postcodes
Surrey
305
305 ppm Very Hard 58
Oxfordshire
304
304 ppm Very Hard 26
Hertfordshire
303
303 ppm Very Hard 53
Buckinghamshire
301
301 ppm Very Hard 26
Berkshire
291
291 ppm Hard 40
East Sussex
271
271 ppm Hard 30
Kent
246
246 ppm Hard 81
Hampshire
244
244 ppm Hard 57
Suppliers

Water Companies in South East

Tap on a company for full coverage area and hardness data.

Affinity Water

268 ppm Hard

Anglian Water

321 ppm Very Hard

Portsmouth Water

261 ppm Hard

Severn Trent Water

222 ppm Hard

Southern Water

263 ppm Hard

Thames Water

302 ppm Very Hard

Hard Water Guides

Learn more about water hardness and how to manage it.

What Is Water Hardness? Hard Water Effects Solutions
Recommended

Products for South East

Top picks for households in hard water areas.

Water2Buy W2B200 Water Softener

From ~£400

Best-value whole-house ion-exchange softener for UK homes. Eliminates limescale from pipes, boilers, and appliances. Digital metered regeneration — low salt use. 7-year warranty.

View on Amazon

Philips AWP1775 Shower Filter

From ~£30

Instant improvement for skin and hair. Reduces chlorine and limescale at the showerhead — no plumbing needed. A good first step before committing to a full softener.

View on Amazon
FAQ

Common questions about South East water

Is tap water in South East safe to drink?
Yes. All tap water in South East meets UK drinking water standards. Hardness affects taste and limescale buildup but not safety.
Why is water in South East hard?
Water hardness in South East depends on the geology — chalk and limestone aquifers dissolve calcium and magnesium into the supply, making it harder. Areas with sandstone or granite tend to be softer.
Does hard water affect boilers in South East?
Over time, limescale acts as an insulator in heat exchangers, reducing efficiency by a few percentage points each year if untreated. A water softener can help protect your boiler.
What's the average water hardness in South East?
The average water hardness across South East is 274 ppm (parts per million), classified as hard. It ranges from 163 ppm to 350 ppm across 352 postcode districts.

Get South East Water Updates

Be notified when water companies in South East report changes to hardness levels.