Scottish Water has launched the procurement process for up to £150M of work over the next six years.
The utility firm called for expressions of interest in framework places to deliver capital works during asset management period 6.
Up to four contractors will be chosen to deliver the work, which will involve design and construction associated with clean water assets.
A notice published in the Official Journal of the European Union said: “It is anticipated that the Tier 1 delivery partners will not subcontract work other than to Scottish Water Tier 2 framework contractors.
“Applicants should therefore have the inhouse resources to self-deliver the work allocated to them.”
Contractors have until midday on 16 July to express an interest in the work.