SES Water Water Hardness — Average 239 ppm

Average hardness	239 ppm (Hard)
Hardness range	236 to 242 ppm
Classification	Hard
Districts served	7
Region	Surrey & South London

About SES Water

SES Water (Sutton and East Surrey Water) supplies drinking water to 735,000 people in parts of Surrey, Kent and south London. Chalk boreholes produce hard water.

At 239 ppm on average, SES 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 SES Water customers, and our limescale removal guide has quick fixes for kettles, taps, and boilers.

Cross-check this against SES Water's own data: SES Water water hardness report. Enter your full postcode to pull your supply zone report showing average hardness plus other drinking water test results.

SES Water vs Other UK Water Companies

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

Rank	Water company	Avg ppm	Classification	Districts
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

Areas Served by SES Water

Every postcode district, sorted by hardness.

Postcode	Town	Hardness	PPM	Level
SM7	Banstead	242	242 ppm	Hard
SM6	Wallington	241	241 ppm	Hard
SM5	Carshalton	240	240 ppm	Hard
SM4	Morden	239	239 ppm	Hard
SM3	Sutton	238	238 ppm	Hard
SM2	Sutton	237	237 ppm	Hard
SM1	Sutton	236	236 ppm	Hard

Products for SES 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.

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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

Common questions about SES Water water hardness

How do I check SES Water hardness by postcode?

Enter your postcode in the checker on the WaterHard.uk homepage, or find your district in the table above. SES Water serves 7 postcode districts across Surrey & South London, ranging from 236 to 242 ppm.

Is there a SES Water hardness checker or map?

SES 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 SES Water water in my area?

It depends on your exact postcode. SES Water supplies range from 236 ppm to 242 ppm, averaging 239 ppm (hard) across 7 postcode districts in Surrey & South London. Use the table above to find your specific district.

Do I need a water softener with SES Water?

At 239 ppm (hard), many households on SES 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.

SES Water Hardness

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SES Water Water Hardness Summary