The project is valued at between £30m and £40m.
The work involves the detailed design, construction and commissioning of a large diameter water mains, running from Summergrove near Whitehaven to Williamsgate, north of Cockermouth.
The scheme is part of United's West Cumbria Water Supply Project and the start of the procurement process follows a public consultation.
The deadline for requests to participate is 17 November 2015.
Further information is on the official OJEU notice.