The company said the new mains will improve the water supply network, and allow it to respond more effectively to operational issues such as burst water mains and minimise disruption to customers.
The work, which is expected to take about four years, will enable Scottish Water to transfer water from Glasgow to Ayrshire and vice-versa if required, creating a “more robust” and connected supply zone which will benefit customers.
The firm said its investment will enable easier maintenance of the water supply network without impacting customers, and will support the Ayrshire economy by reducing the risk of disrupting businesses, making the area more attractive for investment and helping it continue to grow.
Scottish Water chief executive Douglas Millican said: “This major strategic investment scheme, which will deliver a more resilient water supply network for Ayrshire, is the first stage in our investment to improve connections between water supply networks across Scotland.
“We have invested significantly in improvements to water quality in parts of Ayrshire in recent years and now, as proposed in our strategic projections, we will improve much of the area’s water supply resilience by creating a new link between the supply systems.
“The investment in new pipelines and associated infrastructure below ground will support the continued development above ground in communities across these areas and will enable them to continue to grow and thrive.
“It’s a very important and much-needed project which will benefit people in much of Ayrshire and part of East Renfrewshire for decades to come.”