Thames Water Utilities Ltd, known as Thames Water, is the private utility company responsible for the public water supply and waste water treatment in large parts of Greater London, the Thames Valley, Surrey, Gloucestershire, Wiltshire, Kent, and some other areas of the United Kingdom. Thames Water is the UKs largest water and wastewater services company, and supplies 2.6 billion litres (570 million imperial gallons) of drinking water per day, and treats 4.4 billion litres (970 million imperial gallons) of wastewater per day. Thames Waters 15 million customers comprise 27% of the UK population. Thames Water is responsible for a range of water management infrastructure projects including: the Thames Water Ring Main around London; the Lee Tunnel; Europes largest wastewater treatment works and the UKs first large-scale desalination plant, both at Beckton. Thames Water awarded Bazalgette Tunnel Ltd the contract to build the £4.2 billion London Tideway Tunnel Infrastructure proposals by Thames Water include the proposed reservoir at Abingdon, Oxfordshire, which would be the largest enclosed or bunded reservoir in the UK. Thames Water is regulated under the Water Industry Act 1991 and is owned by Kemble Water Holdings Ltd, a consortium formed in late 2006 by Australian-based Macquarie Groups European Infrastructure Funds specifically for the purpose of purchasing Thames Water. Other large shareholders in recent years include: BT Pension Scheme (13%), the Abu Dhabi Investment Authority (9.9%) and the China Investment Corporation (8.7%). The name of the company reflects its role providing water to the drainage basin of the River Thames and not the source of its water, which is taken from a range of rivers and boreholes.