Water hardness

CF15 Cardiff

Near or below the UK average. Limescale builds slowly.

At 39 ppm, Cardiff ranks near the UK's softest water areas — compare it against the hardest areas.

Soft 39 ppm Wales Welsh Water (Dwr Cymru)
Your reading
39
parts per million
Soft
Moderate
Hard
Very hard
0100200300400+

What this means for your home

Based on 39 ppm in Cardiff (soft water).

  • Soap lathers easily with less product needed
  • Minimal limescale buildup in appliances
  • Gentle on skin and hair
  • May taste slightly flat compared to harder water
Heat loss
1%
Minimal scaling
Softener salt
£2–4
per year
Worth it?
No
at 39 ppm
Suggested for soft water
Filter jug (optional)
Mainly a taste preference, limescale won't be a real issue here.
From £20
Maintenance habits
Routine descaling once or twice a year is plenty.
Free
Softening

Should you soften the water in Cardiff?

A verdict and running-cost estimate based on CF15's 39 ppm reading, for a typical 4-person household.

Softener optional

Water is soft to moderate, so limescale and soap costs are low and a softener rarely pays back.

Recommended size
24k
grain capacity, regenerates ~every 68.7 days
Salt running cost
£2–4
per year (~8 kg salt)
Limescale
1%
est. heater efficiency loss. Minimal scaling
Soap saving
Minimal
Water is already soft, so there is little detergent saving from softening.

Appliance impact at 39 ppm: negligible: appliances reach full expected life. Sized for a 4-person home; regenerates roughly every 69 days (estimate). Figures are conservative estimates and vary with household size and usage.

Water quality details

Hardness data for CF15

Sourced from Welsh Water (Dwr Cymru)'s published water-quality reports and public records.

Hardness measurements

Parts per million (ppm CaCO₃)39
Degrees Clark (°Clark)2.7
Degrees French (°fH)3.9
Degrees German (°dH)2.2
Calcium (mg/L Ca²⁺)16

Supplier and area

Water supplier Welsh Water (Dwr Cymru)
Region Wales
County Cardiff
Hardness band Soft
UK average 207 ppm
Visit Welsh Water (Dwr Cymru) page
Official source
Dwr Cymru Welsh Water water-hardness report

Read the hardness explanation here, then enter your postcode on the linked drinking water quality checker to see your area's calcium and magnesium levels.

Nearby

Other areas near Cardiff

CF14
Cardiff
38ppm
Soft
FAQ

Common questions about CF15

What is the water hardness in CF15 Cardiff?
The water in CF15 Cardiff has a hardness level of 39 ppm (parts per million) calcium carbonate, classified as soft. This is 168 ppm below the UK national average of 207 ppm.
Which water company supplies CF15?
CF15 Cardiff is supplied by Welsh Water (Dwr Cymru). Welsh Water (Dwr Cymru) serves the Wales region.
Is the water in CF15 safe to drink?
Yes. Soft water at 39 ppm is safe to drink. Water hardness affects taste and can cause limescale, but it is not a health risk. In fact, hard water contains beneficial minerals like calcium and magnesium.
How can I reduce water hardness in CF15?
At 39 ppm, the water in CF15 is soft and unlikely to cause significant issues. A jug filter can improve taste, but a water softener is generally not necessary.
What does 39 ppm water hardness mean?
39 ppm means there are 39 parts per million of calcium carbonate dissolved in the water. This is equivalent to 2.7 Clark degrees, 2.2 German degrees, or 3.9 French degrees. Water above 180 ppm is generally considered hard.
What size water softener do I need in CF15?
For a typical 4-person home at 39 ppm, a 24,000 grain softener is a sensible size. It would regenerate roughly every 68.7 days. Larger households or higher daily use need a bigger unit. These figures are conservative estimates.
How much does it cost to run a water softener in CF15?
At 39 ppm, expect to use about 8 kg of salt a year, costing roughly £2–£4/year. Water is soft to moderate, so limescale and soap costs are low and a softener rarely pays back.

Your Cardiff water action plan

Enter your email for the short list of things worth doing at 39 ppm, and the upgrades you can safely ignore.

Check another postcode

Compare hardness across areas before moving or buying a softener.