Bus Depot, Glasgow

Built at a cost of around £20 million, the Caledonia Depot in Glasgow was designed to be the largest bus depot in the UK and house 850 buses. The site was designed with sustainability in mind, supporting First Bus’s ambition to transition its fleet towards zero-emission vehicles and to reduce the environmental impact of depot operations.

Sustainability features across the depot included electric bus charging infrastructure, energy-efficient building systems, and reduced reliance on mains water. Rainwater harvesting formed a central part of this approach, using the depot’s vast roof area to provide a secondary water supply for non-potable uses and reduce the site’s overall environmental footprint.

Stormsaver worked with First Bus to deliver a non-pressurised rainwater harvesting system, tailored to the large roof area and the operational needs of the busy automotive site. The system included an automatic backwashing filtration unit, ensuring reliable water quality while minimising maintenance demands. Because of the available space at the depot, a duplex non-pressurised system was recommended, with an elevated header tank to provide efficient distribution.

A 40,000 litre underground storage tank was installed to capture rainfall, supported by a 5,000 litre header tank which allowed water to gravity feed to usage points. The system was also connected to the site’s Building Management System (BMS), allowing performance to be monitored centrally for ease of management.

Stormsaver’s bi-annual maintenance package ensured ongoing performance optimisation. At the latest service, results showed that the depot relied on mains water for only 29% of its demand, with 71% met through harvested rainwater. This demonstrated the system’s effectiveness in reducing costs, cutting environmental impact, and helping First Bus to meet its wider sustainability targets.