The three and a half year case came to an end after the regulator ruled today that the sewer will remain privately owned.
Ofwat said that Anglian water had failed to provide evidence of a connection between its own sewarage network and the third party facility despite multiple opportunities to do so.
An unnamed appellant took the case to the regulator in September 2011 on the grounds adoption by Anglian Water would be detrimental to their site and that there was no statutory duty for for the water company to take control of the private drainage system.
The regulator ruled: “We consider that because the drains under appeal fall within the of the site, they are not eligible for adoption.”
During the long-running case, Anglian Water expressed concern that the site in question, plus a neighbouring supermarket, drained into one of its foul water sewers and was therefore adoptable.
A survey by the appellant, which was seen by Ofwat, showed there was no connection between the private drainage system and Anglian Water’s sewers.
Anglian Water was unable to provide proof the drains linked up to its network despite its ongoing concerns, and had a request for a CCTV survey to assess whether the drainage system did connect to its system rejected by Ofwat.
A spokesperson from Anglian Water was not immediately available to comment.