- Kelda Group plc has assets of #1.8 billion and employs around 3, 000 people, predominantly in the UK. Its principal subsidiary is Yorkshire Water - one of the ten largest water and sewerage companies in the world - which provides high quality services to approximately 4.5 million people and 140, 000 businesses every day. Kelda also owns the US water supply business Aquarion - one of the ten ...www.keldagroup.com