Scottish Water is looking for contractors to fill a framework worth up to £624M.
The utility company placed a notice in OJEU for the agreement, which will cover capital spending through the Quality & Standards IV capital investment programme for the regulatory period starting 2015.
The framework runs to 2021, and has the potential to be extended for a further six years.
Scottish Water expects to spend up to £52M per year through the agreement.
It will be divided into two lots, one covering civil engineering and the other regarding mechanical and electrical work.
Contractors have until 4 July to register their interest in the work.