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, 2025-26.

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: the data in this publication is unaudited and a subject to change at the end of the year.

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 2025-26 (April to December 2025)

Company	Household connections	Complaints to company	Per 10k (company)	Complaints to CCW	Per 10k (to CCW)
Anglian Water	3,112,980	10,487	33.69	566	1.82
Dŵr Cymru Welsh Water	1,504,167	8,505	56.54	436	2.90
Hafren Dyfrdwy	101,194	133	13.14	22	2.17
Northumbrian Water	1,278,357	3,994	31.24	79	0.62
Severn Trent Water	4,386,041	13,556	30.91	1,409	3.21
South West Water	1,029,624	15,087	146.53	524	5.09
Southern Water	2,088,159	16,432	78.69	973	4.66
Thames Water	6,043,396	86,442	143.04	3,679	6.09
United Utilities	3,390,859	20,232	59.67	663	1.96
Wessex Water	1,286,235	4,832	37.57	93	0.72
Yorkshire Water	2,399,641	22,388	93.30	784	3.27

Water only companies’ performance in 2025-26 (April to December 2025)

Company	Household connections	Complaints to company	Per 10k (company)	Complaints to CCW	Per 10k (to CCW)
Affinity Water	1,520,312	13,008	85.56	513	3.37
Bristol Water	530,130	1,973	37.22	37	0.70
Cambridge Water	143,800	788	54.80	38	2.64
Essex & Suffolk Water	803,987	3,410	42.41	95	1.18
Portsmouth Water	311,663	562	18.03	29	0.93
SES Water	289,973	1,600	55.18	137	4.72
South East Water	1,022,450	5,814	56.86	248	2.43
South Staffs Water	577,105	2,340	40.55	150	2.60

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.