Hampshire · South East

Is Southampton water hard or soft?

Hard at 219 ppm · 23 postcode districts

  • Supplier Severn Trent Water
  • County Hampshire
  • Postcodes 23
Area average
219
ppm CaCO₃
Hard
Soft
Moderate
Hard
Very hard
0100200300400+

Southampton water hardness at a glance

  1. Southampton water is hard, averaging 219 ppm across 23 postcode districts.
  2. That is 12 ppm above the UK average of 207 ppm.
  3. The hardest district is SO45 at 286 ppm; the softest is SO50 at 163 ppm.
  4. The supplier is Severn Trent Water.
  5. Expect limescale on kettles, taps and showerheads; see the water softener guide for sizing and costs.

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The average water hardness in Southampton is 219 ppm, classified as hard. Southampton is served by Severn Trent Water, covering 23 postcode districts across Hampshire in the South East region.

Hardness varies across the area. See the table below for a breakdown by postcode district. SO45 has the hardest water at 286 ppm, while SO50 is the softest at 163 ppm.

By postcode

Water Hardness by Postcode in Southampton

Sorted by hardness. Tap a postcode for full details.

Postcode Water Company Hardness PPM Level
SO45 Severn Trent Water
286
286 ppm Hard
SO43 Severn Trent Water
284
284 ppm Hard
SO42 Severn Trent Water
283
283 ppm Hard
SO41 Severn Trent Water
282
282 ppm Hard
SO40 Severn Trent Water
281
281 ppm Hard
SO32 Severn Trent Water
250
250 ppm Hard
SO31 Severn Trent Water
249
249 ppm Hard
SO30 Severn Trent Water
248
248 ppm Hard
SO24 Severn Trent Water
219
219 ppm Hard
SO23 Severn Trent Water
218
218 ppm Hard
SO22 Severn Trent Water
217
217 ppm Hard
SO21 Severn Trent Water
216
216 ppm Hard
SO20 Severn Trent Water
215
215 ppm Hard
SO19 Severn Trent Water
191
191 ppm Hard
SO18 Severn Trent Water
190
190 ppm Hard
SO17 Severn Trent Water
189
189 ppm Hard
SO16 Severn Trent Water
188
188 ppm Hard
SO15 Severn Trent Water
187
187 ppm Hard
SO14 Severn Trent Water
186
186 ppm Hard
SO53 Severn Trent Water
166
166 ppm Moderately Hard
SO52 Severn Trent Water
165
165 ppm Moderately Hard
SO51 Severn Trent Water
164
164 ppm Moderately Hard
SO50 Severn Trent Water
163
163 ppm Moderately Hard
Suppliers

Water Companies Serving Southampton

Tap for full coverage area and hardness data.

Severn Trent Water

222 ppm Hard

Each water company publishes its own hardness data, so you can cross-check the Southampton figures here against the published hardness data from Severn Trent Water.

Water Hardness Guides

Learn more about water hardness and how to manage it.

What Is Water Hardness? Effects Solutions Water Softeners Limescale Removal
Recommended

Products for Southampton

Popular choices for households dealing with hard water.

Splendid Twin Tank Water Softener

Twin-tank electric softener sized for 1 to 7 bedroom homes. Removes limescale from pipes, boilers, and appliances and delivers continuous soft water, with metered regeneration to keep salt use low.

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Philips Shower Filter

Quick win for skin and hair in hard water areas. Reduces chlorine and limescale, fits standard shower hoses in minutes, no tools needed. Cartridge lasts around 6 months.

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BRITA Marella Water Filter Jug

UK's best-selling filter jug. Reduces limescale, chlorine, and metals for better-tasting tap water. Quick first step alongside a softener.

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FAQ

Common questions about Southampton water

Is Southampton water hard or soft?
Southampton is classified as hard, averaging 219 ppm across 23 postcode districts. Expect visible limescale on kettles and taps within weeks at this level.
Which postcode in Southampton has the hardest water?
SO45 has the hardest water in Southampton at 286 ppm, while SO50 is the softest at 163 ppm. See the full table above for every district.
Which water company supplies Southampton?
Southampton is supplied by Severn Trent Water, covering 23 postcode districts across Hampshire.
Is tap water in Southampton 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.
Do I need a water softener in Southampton?
At 219 ppm, many households in Southampton notice limescale in kettles and showerheads within weeks. A shower filter is the cheapest first step; a whole-house softener gives the most complete protection.
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