UK region

Water hardness in Wales

Average 68 ppm across 205 postcode districts — classified as slightly hard.

  • Range 20–120 ppm
  • Counties 6
  • Suppliers Welsh Water (Dwr Cymru)
Regional average
68
ppm CaCO₃
Slightly Hard
Soft
Moderate
Hard
Very hard
0100200300400+
68
Avg ppm
20
Min ppm
120
Max ppm
205
Postcodes

Water Hardness Across Wales

The average water hardness in the Wales region is 68 ppm, classified as slightly hard. Across 205 postcode districts, hardness ranges from 20 ppm to 120 ppm.

The region is served by Welsh Water (Dwr Cymru). Water hardness varies by county — see the breakdown below or check your specific postcode.

By county

Counties in Wales

Sorted by hardness — see how your county compares.

County Hardness PPM Level Postcodes
Powys
113
113 ppm Slightly Hard 8
Gwent
83
83 ppm Slightly Hard 18
West Wales
72
72 ppm Slightly Hard 51
Cardiff
68
68 ppm Slightly Hard 36
North Wales
66
66 ppm Slightly Hard 67
Mid Wales
43
43 ppm Soft 25
Suppliers

Water Companies in Wales

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

Welsh Water (Dwr Cymru)

68 ppm Slightly Hard

Hard Water Guides

Learn more about water hardness and how to manage it.

What Is Water Hardness? Hard Water Effects Solutions
FAQ

Common questions about Wales water

Is tap water in Wales safe to drink?
Yes. All tap water in Wales meets UK drinking water standards. Hardness affects taste and limescale buildup but not safety.
Why is water in Wales slightly hard?
Water hardness in Wales 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 Wales?
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 Wales?
The average water hardness across Wales is 68 ppm (parts per million), classified as slightly hard. It ranges from 20 ppm to 120 ppm across 205 postcode districts.

Get Wales Water Updates

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