Water Industry Act 1991
The Water Industry Act 1991 (c. 56) is an Act of the United Kingdom Parliament consolidating previous enactments relating to the water supply and the provision of wastewater services in England and Wales. It further implemented recommendations of the Law Commission.
The Act is divided into eight parts and a further 15 Schedules are attached
Part 1 deals with the appointment and duties of the Director General of Water Services.
Part 3 deals with the duties of the water companies with respect to water supply in England and Wales,
Part 4 deals with the duties of the water companies with respect to sewerage.
Part 5 deals with the financial provisions for operating the system
Part 6 gives the water companies certain powers in order to discharge their duties.
Part 7 deals with the provision of information to interested parties
Part 8 deals with miscellaneous details such as limiting the right to prosecute water companies in respect of sewerage offences.
Notable schedule within the act include 4 Customer Service Committees; 5 Pressure and Constancy of Supply; 6 Rights of Entry; 9 & 12 Compensation Provisions.
Part 2 Water Undertakers
As of 1 April 2005 the full list of undertakers was 
- Anglian Water Services Ltd
- Northumbrian Water Ltd
- Severn Trent Water Ltd
- Southern Water Services Ltd
- South West Water Ltd
- Thames Water Utilities Ltd
- United Utilities Water PLC [formerly North West Water Ltd]
- Welsh Water - Dwr Cymru Cyfyngedig
- Wessex Water Services Ltd
- Yorkshire Water Services Ltd
- Water only undertakers
- Bournemouth and West Hampshire Water Plc 1 April 2005
- Bristol Water plc 1 April 2005
- Cambridge Water plc 1 April 2005
- Cholderton and District Water Company Ltd 1 April 2005
- Dee Valley Water plc 1 April 2005
- Folkestone and Dover Water Services Ltd 1 April 2005
- Mid Kent Water Ltd 26 August 2005
- Portsmouth Water Ltd 1 April 2005
- South East Water Ltd 1 April 2005
- South Staffordshire Water plc 30 September 2005
- Sutton and East Surrey Water plc 1 April 2005
- Tendring Hundred Water Services Ltd 1 April 2005
- Three Valleys Water Services plc
Part 3 Water Supply
Part 3 Imposes a duty to maintain an efficient and economical water supply system and proscribes minimum standards of performance in connection with water supply.
Standards of wholesomeness
Clause 67 of the act allows the Secretary of State to proscribe Standards of wholesomeness for water; prescribing the purposes for which the water is to be suitable; substances that are to be present or absent and the concentrations.
- Water Industry Act 1991 (c. 56); HMSO