UK region

Water hardness in Wales

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

  • Range 20 to 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

Wales water hardness at a glance

  1. Wales water is slightly hard, averaging 68 ppm across 205 postcode districts.
  2. That is 139 ppm below the UK average of 207 ppm.
  3. Districts range from 20 ppm to 120 ppm; the hardest county is Powys (113 ppm) and the softest is Mid Wales (43 ppm).
  4. Suppliers: Welsh Water (Dwr Cymru).
  5. Limescale builds slowly at this level, so a softener is not usually needed.

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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.

Is the water in Wales hard or soft? It is slightly hard, with readings from 20 to 120 ppm. Welsh Water (Dwr Cymru) supplies most postcodes in Wales; cross-check against Welsh Water's own water hardness data.

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

Hardness varies notably within Wales: Powys has the hardest water in the region at 113 ppm, while Mid Wales is the softest at 43 ppm. The region spans 6 towns and 205 postcode districts in total.

At 68 ppm, Wales ranks as slightly 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 Wales residents, and our limescale removal guide has quick fixes for kettles and taps.

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

Test Your Water in Wales

At 68 ppm on average, your water is slightly 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

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

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FAQ

Common questions about Wales water

Is Wales's water hard or soft?
Wales is classified as slightly hard water, averaging 68 ppm across 205 postcode districts. Limescale build-up is minimal at this level, though individual postcodes vary.
Is tap water in Wales safe to drink?
Hardness is not a safety issue: the World Health Organization sets no health-based limit for water hardness, so hard and soft water are both fine to drink. Drinking water quality is regulated by the Drinking Water Inspectorate in England and Wales and the Drinking Water Quality Regulator in Scotland, and your water company publishes test results for your area.
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.
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