The contract, which covers the entire Yorkshire region, is set to begin in September and will run to 2020.
Amey will also support Yorkshire Water in protecting homes from sewer flooding and pollution incidents, which equates to more than 100,000 jobs a year.
Yorkshire Water, which has around 55,000km of sewerage pipes across the county, said the repair and maintenance work will improve its response and resolution times when dealing with a customer issue.
Yorkshire Water director of service delivery said: “This major contract has been designed to deliver the best possible service for our customers at the best price with the highest levels of safety.”
Amey chief executive Mel Ewell added: “The awarding of this contract to Amey is testament to the strength of our relationship with Yorkshire Water and their trust in our ability to deliver services to the highest possible standards as well as our considerable experience in the wastewater industry.
“We are delighted to expand the scope of our work with Yorkshire Water. Both our organisations will work together to improve essential services and provide an outstanding customer experience across the region.”
A version of this article first appeared on WWTonline.