Water hardness

SO21 Winchester

Harder than the UK average. Expect visible limescale on kettles and taps.

At 216 ppm, Winchester sits among the UK's hardest water areas — compare it against the softest areas.

Hard 216 ppm South East Severn Trent Water
Your reading
216
parts per million
Soft
Moderate
Hard
Very hard
0100200300400+

What this means for your home

Based on 216 ppm in Winchester (hard water).

  • Significant limescale buildup in kettles, pipes and boilers
  • Soap scum on shower screens and taps
  • Higher energy bills from scale in heating elements
  • Dry skin and dull hair after washing
  • White residue on dishes and glassware
Heat loss
8%
Moderate scaling
Softener salt
£12–21
per year
Worth it?
Yes
at 216 ppm
Suggested for hard water
Whole-house water softener
Best long-term protection for boilers and pipes.
From £600 installed
Shower head filter
A simple first step for limescale on tiles and glass.
From £25
Filter jug or under-sink
Improves taste and reduces kettle scale.
From £20
Softening

Should you soften the water in Winchester?

A verdict and running-cost estimate based on SO21's 216 ppm reading, for a typical 4-person household.

Softener recommended

Hardness is moderate to hard, so a softener cuts scale and soap use and usually pays back over its lifetime.

Recommended size
24k
grain capacity, regenerates ~every 12.4 days
Salt running cost
£12–21
per year (~44 kg salt)
Limescale
8%
est. heater efficiency loss. Moderate scaling
Soap saving
Moderate
Noticeable saving: soaps lather more easily, cutting detergent use.

Appliance impact at 216 ppm: noticeable: boiler/dishwasher life cut without descaling. Sized for a 4-person home; regenerates roughly every 12 days (estimate). Figures are conservative estimates and vary with household size and usage.

Water quality details

Hardness data for SO21

Sourced from Severn Trent Water's published water-quality reports and public records.

Hardness measurements

Parts per million (ppm CaCO₃)216
Degrees Clark (°Clark)15.1
Degrees French (°fH)21.6
Degrees German (°dH)12.1
Calcium (mg/L Ca²⁺)87

Supplier and area

Water supplier Severn Trent Water
Region South East
County Hampshire
Hardness band Hard
UK average 207 ppm
Visit Severn Trent Water page
Official source
Severn Trent Water water-hardness report

Enter your postcode and pick a timeframe to see your area's measured water quality including hardness, with a downloadable PDF report.

Nearby

Other areas near Winchester

SO20
Stockbridge
215ppm
Hard
SO22
Winchester
217ppm
Hard
SO23
Winchester
218ppm
Hard
FAQ

Common questions about SO21

What is the water hardness in SO21 Winchester?
The water in SO21 Winchester has a hardness level of 216 ppm (parts per million) calcium carbonate, classified as hard. This is 9 ppm above the UK national average of 207 ppm.
Which water company supplies SO21?
SO21 Winchester is supplied by Severn Trent Water. Severn Trent Water serves the South East region.
Is the water in SO21 safe to drink?
Yes. Hard water at 216 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 SO21?
For hard water at 216 ppm, a whole-house water softener is the most effective solution. You can also use a jug filter for drinking water, descaling products for appliances, and a shower filter for better skin and hair.
What does 216 ppm water hardness mean?
216 ppm means there are 216 parts per million of calcium carbonate dissolved in the water. This is equivalent to 15.1 Clark degrees, 12.1 German degrees, or 21.6 French degrees. Water above 180 ppm is generally considered hard.
What size water softener do I need in SO21?
For a typical 4-person home at 216 ppm, a 24,000 grain softener is a sensible size. It would regenerate roughly every 12.4 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 SO21?
At 216 ppm, expect to use about 44 kg of salt a year, costing roughly £12–£21/year. Hardness is moderate to hard, so a softener cuts scale and soap use and usually pays back over its lifetime.

Check another postcode

Compare hardness across areas before moving or buying a softener.