UK Water Companies

All 16 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	3
2	Dŵr Cymru Welsh Water	Wales	3M	9.5/10	5
3	Bristol Water	Bristol and surrounding area	1.2M	9.5/10	8
4	Wessex Water	South West	2.8M	9.4/10	2
5	South East Water	South East England	2.2M	9.1/10	1
6	Southern Water	South East	4.7M	8.9/10	4
7	Severn Trent	Midlands	8M	8.8/10	15
8	Yorkshire Water	Yorkshire	5M	8.8/10	11
9	Northumbrian Water	North East	2.7M	8.8/10	5
10	United Utilities	North West	7M	8.7/10	13
11	Portsmouth Water	Hampshire and West Sussex	0.7M	8.5/10	2
12	Thames Water	London and Thames Valley	15M	8.3/10	29
13	Affinity Water	South East England	3.6M	8/10	1
14	South Staffs Water	South Staffordshire and Cambridge	1.6M	7.6/10	1
15	Anglian Water	East of England	4.5M	No data	0
16	Scottish Water	Scotland	5.4M	No data	0

Drinking water test data available