UK Water Companies

All 18 major UK water companies ranked by average water quality score. Click any company to see detailed postcode-level data.

#	Company	Region	Customers	Avg Score	Areas
1	South West Water	Devon and Cornwall	1.8M	9.5/10	4
2	Dŵr Cymru Welsh Water	Wales	3M	9.5/10	5
3	United Utilities	North West	7M	9.4/10	13
4	Yorkshire Water	Yorkshire	5M	9.4/10	11
5	Northumbrian Water	North East	2.7M	9.3/10	5
6	South East Water	South East England	2.2M	9.3/10	1
7	Severn Trent	Midlands	8M	9.1/10	15
8	South Staffs Water	South Staffordshire and Cambridge	1.6M	9.1/10	2
9	Cambridge Water	Cambridge	0.35M	9.1/10	4
10	Southern Water	South East	4.7M	9/10	6
11	Anglian Water	East of England	4.5M	8.9/10	4
12	Wessex Water	South West	2.8M	8.9/10	2
13	Essex & Suffolk Water	Essex and Suffolk	1.8M	8.9/10	6
14	Bristol Water	Bristol and surrounding area	1.2M	8.5/10	8
15	Portsmouth Water	Hampshire and West Sussex	0.7M	8.4/10	2
16	Affinity Water	South East England	3.6M	8.4/10	3
17	Thames Water	London and Thames Valley	15M	8.2/10	30
18	Scottish Water	Scotland	5.4M	No data	0

Drinking water test data available