Cheam softening

Increased water hardness from Cheam and Woodmansterne Treatment Works 

We are pleased to report that we recommenced softening at our Cheam treatment works on the morning of 29 May 2025, following completion of our essential maintenance works.

The hardness of the water leaving Cheam works is at expected levels (c. 80 mg/l of Ca). Customers should start to notice the change over the next couple of days as the stored water stored is replaced. 

The main areas supplied by Cheam treatment works include Cheam, Sutton, Worcester Park, Ewell, Morden, Carshalton, Carshalton Beeches and South Sutton. 
 
Further essential maintenance is ongoing at our Woodmansterene treatment works. 

The softening here, is due to recommence on Monday 2 June. 

The main areas supplied by Woodmansterne include Wallington, Carshalton, Chipstead, Banstead, Burgh Heath, Kingswood, Tadworth and parts of Carshalton Beeches and South Sutton
 
The increased water hardness is of no health concern and the water can be consumed and used as normal. Customers may, however, notice increased deposits of limescale in their kettles, on glassware or on taps, draining boards or sanitary ware. Some customers may also notice a slight change to the taste of their water. Information is covered within our Scale and Hardness factsheet, Hardness and Scale Factsheet, and includes information in minimising scale formation.

To learn more about Water Quality in your area, or to read our factsheets, visit our Water Quality page. 

SES Water is unique in the water industry in having a legal obligation to soften the groundwater we treat, and we have made significant capital investment in our softening capability over recent years. We are also proud of our water quality, which is industry leading as confirmed by the Drinking Water Inspectorate (DWI) in its 2024 report.
We want to thank you for your patience and understanding while these repairs have been ongoing.

Page last updated 29/05/25

FAQs:

Why do you need to soften the water?

We are unique in the water industry in having a legal obligation to soften the groundwater we treat, and we have made significant capital investment in our softening capability over recent years.

We are also extremely proud of our water quality, which is industry-leading as confirmed by the Drinking Water Inspectorate (DWI) in its 2024 report.

Why did you stop softening my water?

We had to temporarily pause our operation to soften the water while we made important repairs to our softening infrastructure. 

My water tastes odd, are there any health risks if I drink it?

We’d like to reassure you there are no health concerns associated with the increased water hardness and the water can be consumed and used as normal. You may however have noticed a slight change to the taste of your water, an increase in limescale and a film on cups of tea, for example.

If you’d like more information on increased scale and water hardness you can read our factsheet here.

I have a number of medical conditions and am worried this water will affect my health – how can you help?

We’d like to reassure you there are no health concerns associated with the increased water hardness and the water can be consumed and used as normal.

If you need any additional support, we’re here to help and you can contact our Extra Care team on 01737 785606. Or email us at extracare@seswater.co.uk.

Will you providing me with compensation?

We will not be compensating customers directly. Water softening is a performance commitment with our regulator, Ofwat, and we receive a financial penalty if we do not meet our softening targets. Any financial penalty is deducted from the subsequent year's revenue we are able to collect from customers. Therefore, next year's bill will reflect any penalty for the current year's performance. To confirm, in this instance we would reduce the amount we can collect from customers, rather than issuing a refund.

Is this just another example of water companies under investing in their infrastructure?

We are unique in the water industry in having a legal obligation to soften the groundwater we treat, and we have made significant capital investment in our softening capability over recent years.

The repairs we need to make are routine and our teams are working as hard and fast as possible to return our customers’ water hardness to normal levels.

Did you stop water softening as you are now part of the Pennon Group?

Our softening operation has not been impacted in any way since becoming part of the Pennon Group.

Is water softening another way of saving money?

Water softening is an expensive process, which we a have a legal obligation to maintain. Furthermore we have made significant capital investment in our softening capability over recent years.

Ofwat hasn’t approved plans to increase bills, is this SES Water beginning to implement cost-cutting measures?

We have only temporarily paused our softening process while we make important repairs to our infrastructure. As soon as these repairs have been completed we will resume softening as normal.