Water suppliers are the companies that provide water only and water and sewerage for general domestic use to the UK's homes. Suppliers are responsible for all customers in an agreed geographical region and customers are currently unable to switch from one water supplier to another.
To cover the cost of supplying you with water and sewerage services, water suppliers charge customers a yearly water rate. The water rates are regulated by Ofwat, the water industry regulator. Every five years the water suppliers suggest the prices they would like to set and Ofwat reviews and decides on a price to suit both the suppliers and customers.
Water rates as well as covering day to day services need to cover the cost of renewing water pipes and treatment plants to maintain the quality of water and to improve customer services. Water suppliers do charge different rates and these differences are due to the geographical area which the company covers and water availability.