UK region

Water hardness in South West

Average 161 ppm across 278 postcode districts — classified as moderately hard.

  • Range 27–291 ppm
  • Counties 7
  • Suppliers Severn Trent Water, South West Water, Wessex Water
Regional average
161
ppm CaCO₃
Moderately Hard
Soft
Moderate
Hard
Very hard
0100200300400+
161
Avg ppm
27
Min ppm
291
Max ppm
278
Postcodes

Water Hardness Across South West

The average water hardness in the South West region is 161 ppm, classified as moderately hard. Across 278 postcode districts, hardness ranges from 27 ppm to 291 ppm.

The region is served by Severn Trent Water, South West Water, Wessex Water. Water hardness varies by county — see the breakdown below or check your specific postcode.

At 161 ppm, South West ranks as moderately hard water nationally. Compare it against the 50 softest water areas in the UK.

Worth reading: our water softener guide covers the best options for South West residents, and our limescale removal guide has quick fixes for kettles and taps.

By county

Counties in South West

Sorted by hardness — see how your county compares.

County Hardness PPM Level Postcodes
Bristol
238
238 ppm Hard 37
Gloucestershire
233
233 ppm Hard 27
Dorset
225
225 ppm Hard 37
Wiltshire
211
211 ppm Hard 29
Somerset
139
139 ppm Moderately Hard 43
Cornwall
91
91 ppm Slightly Hard 23
Devon
86
86 ppm Slightly Hard 82
Suppliers

Water Companies in South West

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

Severn Trent Water

222 ppm Hard

South West Water

80 ppm Slightly Hard

Wessex Water

231 ppm Hard

Hard Water Guides

Learn more about water hardness and how to manage it.

What Is Water Hardness? Hard Water Effects Solutions

Test Your Water in South West

At 161 ppm on average, your water is moderately hard. A home testing kit lets you verify the exact hardness for your postcode and check for other contaminants.

TESPERT 16-in-1 Water Testing Kit

From ~£10

Home water test strips that check hardness, pH, chlorine, lead, and 12 other parameters. Results in around 60 seconds. 125 strips per pack.

View on Amazon
FAQ

Common questions about South West water

Is South West's water hard or soft?
South West is classified as moderately hard water, averaging 161 ppm across 278 postcode districts. Limescale build-up is minimal at this level, though individual postcodes vary.
Is tap water in South West safe to drink?
Yes. All tap water in South West meets UK drinking water standards. Hardness affects taste and limescale buildup but not safety.
Why is water in South West moderately hard?
Water hardness in South West 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 West?
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 West?
The average water hardness across South West is 161 ppm (parts per million), classified as moderately hard. It ranges from 27 ppm to 291 ppm across 278 postcode districts.

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