Where any part of a sewer is vested in a sewerage undertaker by virtue of section 70 of the Water Act 1989 (cross boundary sewers), the terms on which that part of that sewer—
as immediately before 1st September 1989 were vested in the same water authority as that part of that sewer but, by virtue of that section, are vested in another sewerage undertaker shall be determined, in default of agreement, by the Authority.
A determination by the Authority under this section shall have effect as an agreement between the sewerage undertakers in question but may be varied or revoked by a subsequent determination made by the Authority on the application of either of those undertakers, as well as by agreement between the undertakers.
In making a determination under this section, the Authority shall have regard to the desirability of a sewerage undertaker's recovering the costs resulting from its allowing the sewers of other sewerage undertakers to communicate with its sewers or to discharge into its sewage disposal works and of its securing a reasonable return on its capital.