Their supply area

They are the UK's largest water and wastewater services company.

Every day, they supply around 2,600 million litres of tap water to 9 million customers across London and the Thames Valley. They also remove and treat more than 4 billion litres of sewage for 15 million customers.

How the water retail market works

All businesses, charities and public sector organisations (non-household customers) in England, Scotland and Wales can choose their water retailer –similar to electricity, gas and telecoms services. To enable competition, water companies’ activities have been split into retail and wholesale.

Retail explained

Retail services include all customer-facing activities: billing, account-handling (payments, debt management, meter reading), customer queries, as well as water-efficiency advice and tackling customer side leaks.

All their non-household customers were transferred to Castle Water when the competitive market opened. If you’re a non-household customer and you haven’t switched suppliers since, your water retailer will still be Castle Water.

Wholesale explained

Wholesalers like us are responsible for managing the water and wastewater networks, such as the pipes to and from customers’ property boundaries. This also includes the sourcing, treatment and transporting of water, as well as the collection, treatment and getting rid of wastewater.

They employ field teams to maintain pipes, fix leaks and restore water and wastewater supplies across their networks.

Their history

Their history dates back to the 1600s with the creation of the New River.

It features some pretty impressive engineering projects, record-breaking investment, UK firsts and water industry-leading initiatives.