Complaint performance

We share information with household customers about how their water companies handle complaints each quarter. This data comes from complaints made directly to the water companies and those reported to us.

How we measure performance

For this quarterly complaints update, we use two sources to understand how companies are performing with complaints:

complaints received directly by the companies; and
complaints raised directly to CCW about the companies

This update focuses on the complaints performance for the current year, 2026-27.

How we compare performance

To compare companies of different sizes, we use a metric called ‘complaints per 10,000 connections’. This metric takes into account the number of water and wastewater connections each company serves.

For example, if Company A received 600 complaints and has 4,000,000 total connections, the calculation would be:

Complaints per 10,000 connections = 600/4,000,000 x 10,000 = 1.5

Comparative performance: we compare the performance of individual companies within their respective segments as either Water and Sewerage Companies (WaSCs) or Water Only Companies (WOCs).

Important note: This publication is based on unaudited in-year data and should be treated as indicative. Figures may be revised following data quality reviews and the annual audit process.

How we measure
Quartile 1 – Good
Quartile 2 – Better than median*
Quartile 3 – At or worse than median*
Quartile 4 – Poor

*Median – a mid-point of the data set, or a middle value in the list of numbers that are arranged by highest to lowest.

Water and sewerage companies’ performance in 2026-27 (April to June 2026)

Company	Household connections	Complaints to company	Per 10k (company)	Complaints to CCW	Per 10k (to CCW)
Anglian Water	3,129,321	3,244	10.37	186	0.59
Dŵr Cymru Welsh Water	1,516,956	3,507	23.12	136	0.90
Hafren Dyfrdwy	101,868	58	5.69	8	0.79
Northumbrian Water	1,292,299	1,077	8.33	34	0.26
Severn Trent Water	4,421,097	4,596	10.40	456	1.03
South West Water	1,034,221	3,720	35.97	176	1.70
Southern Water	2,099,743	4,128	19.66	436	2.08
Thames Water	6,206,608	30,929	49.83	1,491	2.40
United Utilities	3,424,312	5,734	16.74	201	0.59
Wessex Water	1,292,046	1,729	13.38	28	0.22
Yorkshire Water	2,416,975	5,675	23.48	311	1.29

Water only companies’ performance in 2026-27 (April to June 2026)

Company	Household connections	Complaints to company	Per 10k (company)	Complaints to CCW	Per 10k (to CCW)
Affinity Water	1,526,640	5,177	33.91	182	1.19
Bristol Water	531,375	698	13.14	11	0.21
Cambridge Water	145,268	271	18.66	12	0.83
Essex & Suffolk Water	807,110	928	11.50	29	0.36
Portsmouth Water	313,932	246	7.84	6	0.19
SES Water	298,761	441	14.76	61	2.04
South East Water	948,051	1,937	20.43	100	1.05
South Staffs Water	579,235	931	16.07	67	1.16

Complaint trend

Below, you’ll find graphs that track how company complaint trends changed over time. First graph shows complaints received by company per 10,000 connections, while the other illustrates complaints reported directly to CCW per 10,000 connections.