C-MeX and D-MeX - 2021-22 results

Residential customers in England and Wales cannot choose their water and wastewater company. Developers and other third parties must also receive certain services from one of the 17 largest water only and water and wastewater companies we regulate.

We encourage the 17 companies providing these monopoly services to deliver better services by (among other things) using incentives. This includes:

  • the Customer Measure of Experience (C-MeX), which measures the quality of services delivered to household customers
  • the Developer Services Measure of Experience (D-MeX), which measures the quality of services to developers and other third parties

Each company is ranked for C-MeX and D-MeX and receive:

  • a positive financial payment if they do better than expected (‘outperformance’)
  • a negative financial payment if they do worse (‘underperformance’).

Performance commitments are the pledges companies made to their customers and stakeholders at the 2019 price review (PR19) about service levels to make progress towards their outcomes. Where a company outperforms against its performance commitments, it sees relevant increases in the amount of revenue it can recover in its price controls. Where a company underperforms against its performance commitments, this reduces the amount of revenue companies can recover from customers.

The financial payments associated with C-MeX and D-MeX will be detailed in the companies in period draft determinations and these outperformance and underperformance payments will be confirmed as final at final determination stage of the in period process.

Customer Measure of Experience (C-MeX) 2021-22 results

Rank Company C-Mex score
1 Wessex Water 84.82
2 Northumbrian Water 84.46
3 Portsmouth Water 83.76
4 South Staffs Water 83.38
5 Welsh Water 82.93
6 Bristol Water 82.86
7 United Utilities 82.01
8 Severn Trent Water 80.61
9 Anglian Water 80.43
10 Yorkshire Water 80.41
11 Hafren Dyfrdwy 78.78
12 South West Water 78.48
13 South East Water 76.59
14 Affinity Water 76.57
15 SES Water 76.35
16 Southern Water 72
17 Thames Water 68.86

 

Developer Services Measure of Experience (D-MeX) 2021-22 results

Rank Company D-Mex score
1 Hafren Dyfrdwy 91.27
2 Severn Trent Water 90.9
3 Portsmouth Water 90.56
4 Wessex Water 89.65
5 Northumbrian Water 88.56
6 United Utilities 88.4
7 Anglian Water 87.54
8 Affinity Water 85.54
9 Bristol Water 85.26
10 South West Water 84.99
11 South Staffs Water 84.4
12 Welsh Water 83.94
13 South East Water 81.34
14 Thames Water 79.64
15 Southern Water 77.78
16 SES Water 77.39
17 Yorkshire Water 55.08

 

About C-MeX and D-MeX

We publish league tables each year which show how each company has performed during the year and an

How C-MeX is measured

C-MeX is based on two surveys conducted each month with residential customers:

  • the customer service survey (CSS) – based on interviews with a random sample of customers that have recently contacted their company, using a mixture of telephone and online surveys; and
  • the customer experience survey (CES) – based on interviews with a random sample of members of the public, using a mixture of telephone and face-to-face surveys.

How D-MeX is measured

D-MeX has two components which measure the service provided by water companies to their developer services customers (which include large and small property developers, self-lay providers, new appointees and other customers requesting a new connection):

  • a qualitative component – based on monthly interviews with developer services customers that have transacted with a water company in the previous month
  • a quantitative component – based on the water company’s performance against a key set of Water UK metrics which measure the service provided by water companies to their developer services customers.