If you're a domestic customer and currently live in the Anglian Water region you cannot obtain water and water recycling services from another company. 
 

You can’t choose another water company because household water services in the UK are divided up geographically, meaning each area is served by one designated supplier. This setup is based on UK regulations, which assign Anglian Water to your region and don’t allow domestic customers to switch.

Currently, only Business Customers can chose a different retailer.