South East England · Water company

Southern Water Hardness

Average 263 ppm across 131 postcodes served.

  • Range 200–350 ppm
  • Region South East England
  • Postcodes 131
Company average
263
ppm CaCO₃
Hard
Soft
Moderate
Hard
Very hard
0100200300400+
263
Avg ppm
200
Min ppm
350
Max ppm
131
Postcodes

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Southern Water Water Hardness Summary

Southern Water water is hard, averaging 263 ppm as calcium carbonate, ranging from 200 to 350 ppm across 131 postcode districts in South East England.

Average hardness263 ppm (Hard)
Hardness range200 to 350 ppm
ClassificationHard
Districts served131
RegionSouth East England

About Southern Water

Southern Water provides water and wastewater services to 2.6 million customers across Kent, Sussex, Hampshire and the Isle of Wight. The chalk downs of southern England produce notably hard water.

At 263 ppm on average, Southern Water ranks as hard water. See how it compares across the UK in our 50 hardest water areas ranking.

Worth reading: our water softener guide compares the options for Southern Water customers, and our limescale removal guide has quick fixes for kettles, taps, and boilers.

Cross-check this against Southern Water's own data: Southern Water water hardness report. Enter your postcode in the hard water checker to get your hardness band and a full water quality report in mg/l, Clarke, French or German degrees.

Comparison

Southern Water vs Other UK Water Companies

Average hardness across the 15 largest UK water suppliers, hardest first. Your supplier is highlighted.

RankWater companyAvg ppmClassificationDistricts
1 Anglian Water 321 ppm Very Hard 261
2 Thames Water 302 ppm Very Hard 412
3 South East Water 297 ppm Hard 17
4 Affinity Water 268 ppm Hard 32
5 Southern Water 263 ppm Hard 131
6 Portsmouth Water 261 ppm Hard 34
7 SES Water 239 ppm Hard 7
8 Wessex Water 231 ppm Hard 123
9 Severn Trent Water 222 ppm Hard 345
10 Yorkshire Water 215 ppm Hard 217
11 Northumbrian Water 101 ppm Slightly Hard 122
12 South West Water 80 ppm Slightly Hard 129
13 United Utilities 77 ppm Slightly Hard 242
14 Welsh Water (Dwr Cymru) 68 ppm Slightly Hard 214
15 Scottish Water 54 ppm Soft 3
Distribution

Hardness Breakdown

0
Soft
(0%)
0
Slightly Hard
(0%)
0
Moderate
(0%)
97
Hard
(74%)
34
Very Hard
(26%)
All areas

Areas Served by Southern Water

Every postcode district, sorted by hardness.

Postcode Town Hardness PPM Level
TN10 Tonbridge
350
350 ppm Very Hard
RH20 Pulborough
344
344 ppm Very Hard
RH9 Godstone
329
329 ppm Very Hard
RH8 Oxted
328
328 ppm Very Hard
RH7 Lingfield
327
327 ppm Very Hard
RH6 Horley
326
326 ppm Very Hard
RH5 Dorking
325
325 ppm Very Hard
RH4 Dorking
324
324 ppm Very Hard
RH3 Betchworth
323
323 ppm Very Hard
RH2 Reigate
322
322 ppm Very Hard
BN45 Brighton
321
321 ppm Very Hard
RH1 Redhill
321
321 ppm Very Hard
BN44 Steyning
320
320 ppm Very Hard
RH19 East Grinstead
320
320 ppm Very Hard
BN43 Shoreham By Sea
319
319 ppm Very Hard
RH18 Forest Row
319
319 ppm Very Hard
BN42 Brighton
318
318 ppm Very Hard
RH17 Haywards Heath
318
318 ppm Very Hard
BN41 Brighton
317
317 ppm Very Hard
BN9 Newhaven
317
317 ppm Very Hard
RH16 Haywards Heath
317
317 ppm Very Hard
BN8 Lewes
316
316 ppm Very Hard
RH15 Burgess Hill
316
316 ppm Very Hard
BN7 Lewes
315
315 ppm Very Hard
RH14 Billingshurst
315
315 ppm Very Hard
BN6 Hassocks
314
314 ppm Very Hard
RH13 Horsham
314
314 ppm Very Hard
BN5 Henfield
313
313 ppm Very Hard
RH12 Horsham
313
313 ppm Very Hard
RH11 Crawley
312
312 ppm Very Hard
BN3 Hove
311
311 ppm Very Hard
RH10 Crawley
311
311 ppm Very Hard
BN2 Brighton
310
310 ppm Very Hard
BN1 Brighton
309
309 ppm Very Hard
TN40 Bexhill On Sea
298
298 ppm Hard
CT21 Hythe
291
291 ppm Hard
CT20 Folkestone
290
290 ppm Hard
TN9 Tonbridge
289
289 ppm Hard
TN8 Edenbridge
288
288 ppm Hard
TN7 Hartfield
287
287 ppm Hard
TN6 Crowborough
286
286 ppm Hard
TN5 Wadhurst
285
285 ppm Hard
TN4 Tunbridge Wells
284
284 ppm Hard
TN3 Tunbridge Wells
283
283 ppm Hard
TN2 Tunbridge Wells
282
282 ppm Hard
TN1 Tunbridge Wells
281
281 ppm Hard
TN39 Bexhill On Sea
274
274 ppm Hard
TN38 St Leonards On Sea
273
273 ppm Hard
TN37 St Leonards On Sea
272
272 ppm Hard
TN36 Winchelsea
271
271 ppm Hard
TN35 Hastings
270
270 ppm Hard
TN34 Hastings
269
269 ppm Hard
TN33 Battle
268
268 ppm Hard
TN32 Robertsbridge
267
267 ppm Hard
CT19 Folkestone
266
266 ppm Hard
TN31 Rye
266
266 ppm Hard
CT18 Folkestone
265
265 ppm Hard
TN30 Tenterden
265
265 ppm Hard
CT17 Dover
264
264 ppm Hard
CT16 Dover
263
263 ppm Hard
CT15 Dover
262
262 ppm Hard
CT14 Deal
261
261 ppm Hard
CT13 Sandwich
260
260 ppm Hard
CT12 Ramsgate
259
259 ppm Hard
CT11 Ramsgate
258
258 ppm Hard
BN27 Hailsham
257
257 ppm Hard
CT10 Broadstairs
257
257 ppm Hard
BN26 Polegate
256
256 ppm Hard
BN25 Seaford
255
255 ppm Hard
BN24 Pevensey
254
254 ppm Hard
BN23 Eastbourne
253
253 ppm Hard
ME20 Aylesford
253
253 ppm Hard
BN22 Eastbourne
252
252 ppm Hard
BN21 Eastbourne
251
251 ppm Hard
BN20 Eastbourne
250
250 ppm Hard
CT9 Margate
245
245 ppm Hard
CT8 Westgate On Sea
244
244 ppm Hard
CT7 Birchington
243
243 ppm Hard
CT6 Herne Bay
242
242 ppm Hard
CT5 Whitstable
241
241 ppm Hard
TN29 Romney Marsh
241
241 ppm Hard
CT4 Canterbury
240
240 ppm Hard
TN28 New Romney
240
240 ppm Hard
CT3 Canterbury
239
239 ppm Hard
TN27 Ashford
239
239 ppm Hard
CT2 Canterbury
238
238 ppm Hard
TN26 Ashford
238
238 ppm Hard
CT1 Canterbury
237
237 ppm Hard
TN25 Ashford
237
237 ppm Hard
TN24 Ashford
236
236 ppm Hard
TN23 Ashford
235
235 ppm Hard
TN22 Uckfield
234
234 ppm Hard
TN21 Heathfield
233
233 ppm Hard
TN20 Mayfield
232
232 ppm Hard
ME19 West Malling
229
229 ppm Hard
ME18 Maidstone
228
228 ppm Hard
ME17 Maidstone
227
227 ppm Hard
ME16 Maidstone
226
226 ppm Hard
BN18 Arundel
225
225 ppm Hard
ME15 Maidstone
225
225 ppm Hard
BN17 Littlehampton
224
224 ppm Hard
ME14 Maidstone
224
224 ppm Hard
BN16 Littlehampton
223
223 ppm Hard
ME13 Faversham
223
223 ppm Hard
BN15 Lancing
222
222 ppm Hard
ME12 Sheerness
222
222 ppm Hard
BN14 Worthing
221
221 ppm Hard
ME11 Queenborough
221
221 ppm Hard
ME9 Sittingbourne
221
221 ppm Hard
BN13 Worthing
220
220 ppm Hard
ME10 Sittingbourne
220
220 ppm Hard
ME8 Gillingham
220
220 ppm Hard
BN12 Worthing
219
219 ppm Hard
ME7 Gillingham
219
219 ppm Hard
BN11 Worthing
218
218 ppm Hard
ME6 Snodland
218
218 ppm Hard
BN10 Peacehaven
217
217 ppm Hard
ME5 Chatham
217
217 ppm Hard
ME4 Chatham
216
216 ppm Hard
ME3 Rochester
215
215 ppm Hard
ME2 Rochester
214
214 ppm Hard
ME1 Rochester
213
213 ppm Hard
TN19 Etchingham
208
208 ppm Hard
TN18 Cranbrook
207
207 ppm Hard
TN17 Cranbrook
206
206 ppm Hard
TN16 Westerham
205
205 ppm Hard
TN15 Sevenoaks
204
204 ppm Hard
TN14 Sevenoaks
203
203 ppm Hard
TN13 Sevenoaks
202
202 ppm Hard
TN12 Tonbridge
201
201 ppm Hard
TN11 Tonbridge
200
200 ppm Hard
Recommended

Products for Southern Water Customers

Popular choices for households on hard water.

Splendid Twin Tank Water Softener

From ~£400

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.

View on Amazon

Philips Shower Filter

From ~£30

A quick, affordable upgrade. Reduces chlorine and limescale at the showerhead, fits any standard UK shower hose in minutes. Protects skin and hair from hard water damage.

View on Amazon
FAQ

Common questions about Southern Water water hardness

How do I check Southern Water hardness by postcode?
Enter your postcode in the checker on the WaterHard.uk homepage, or find your district in the table above. Southern Water serves 131 postcode districts across South East England, ranging from 200 to 350 ppm.
Is there a Southern Water hardness checker or map?
Southern Water publishes water quality data by postcode, but it can be scattered across PDF reports. WaterHard.uk compiles it into the searchable table above so you can find your district's reading in one place.
How hard is Southern Water water in my area?
It depends on your exact postcode. Southern Water supplies range from 200 ppm to 350 ppm, averaging 263 ppm (hard) across 131 postcode districts in South East England. Use the table above to find your specific district.
Do I need a water softener with Southern Water?
At 263 ppm (hard), many households on Southern Water 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. See our water softener guide for a full comparison.
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