Amey has secured a £129M deal with Affinity Water.
The contractor will deliver metering installations as well as planned and reactive maintenance under a five-year deal with the utility firm.
Affinity provides 900M litres of water each day to more than 3.5M people across South East England.
Amey chief executive Mel Ewell said: “Our teams have a proven track record of employing a range of innovative technologies to minimise disruption for customers and the local community, in line with Affinity Water’s vision.
“I’m delighted that we are further cementing our relationship through this new contract, supporting Affinity Water in providing a value for money service, and ensuing a reliable supply of high quality drinking water.”