Scottish Water has completed a record £235 million investment to strengthen and future-proof the drinking water supply for almost one million people across the west of Scotland. The project creates a new two-way connection between the drinking water networks serving Greater Glasgow, Ayrshire and East Renfrewshire, enabling the transfer of tens of millions of litres of water in either direction and significantly boosting resilience in the event of network issues.
The major engineering programme links the Milngavie Water Treatment Works (WTW), which serves over 700,000 people in Greater Glasgow, with the Bradan WTW system, which supplies more than 200,000 customers across Ayrshire and a further 50,000 in East Renfrewshire. The new network now stretches almost 100 miles from Loch Katrine in Stirlingshire to Loch Bradan in South Ayrshire, providing a more flexible and secure system for customers.
The investment includes a strong focus on sustainability and energy efficiency, with materials and design approaches to reduce carbon emissions, solar panels at pumping stations and gravity-fed operation
Delivered through the Caledonia Water Alliance, formed by Morrison Water Services (now part of M Group Water) and AECOM, the project involved installing more than 37 miles of new strategic water mains—30 miles across Ayrshire and 7.5 miles in southwest Glasgow—along with a new pumping station at Ibrox. The final phase of works, carried out between 2021 and 2025, included four new tunnels under major transport routes such as the M8 motorway and the Glasgow–Ayr railway line.
“This is a massive boost for the west of Scotland,” said Rob Mustard, Director of Capital Investment. “It means the water network is more robust, enabling more secure delivery of tens of millions of litres of drinking water to homes. It allows us to respond more quickly to operational issues such as mains bursts, ensuring people continue to have access to Scotland’s world-class drinking water when they need it.”
The new interconnected network improves operational flexibility, allowing supply from both ends in the event of a burst main, which reduces disruption and repair times. It also supports the organisation’s long-term strategy to provide sustainable, resilient, and affordable services for the future.
The investment includes a strong focus on sustainability and energy efficiency. Innovative materials and design approaches have reduced carbon emissions, while 793 solar panels installed at the Ibrox and Parkhouse/Darnley pumping stations offset around 78 tonnes of CO₂ equivalent each year. The system’s gravity-fed operation also cuts energy use by approximately 60%.
Climate Action Secretary Gillian Martin said: “This investment is essential to increase resilience, ensuring water networks can respond quickly to any unforeseen events and continue to supply customers with high quality drinking water. It is a good example of why this government is committed to the public ownership of our water industry – as all profits go back into improving the service for customers, never to shareholders.”
