New monitoring equipment installed in 2024 revealed more than 100,000 sewage spills across Scotland, as monitoring coverage expanded from 6% to 30%.
The addition of 1,009 sewer monitors in 2024 provided a more detailed view of the nation’s wastewater infrastructure. While previous figures recorded 24,000 spills, experts note that those numbers were limited by lower coverage, making direct comparisons difficult.
Scottish Water’s overflow sites are licensed to discharge untreated or partially treated waste into waterways, though just under 12% of overflows are legally required to report their data to the Scottish Environment Protection Agency (Sepa).
How Waterways Bear The Burden
Data from Scottish Water identified Glasgow’s River Clyde as one of the most impacted waterways in Scotland last year, receiving almost 6,150 spills. When the Clyde Estuary, Firth of Clyde and other unnamed tributaries are included, that figure rises to nearly 14,200 spills.
The Clyde Estuary also experienced the longest duration of overflow activity, totaling more than 25,000 hours, followed by the River Clyde with more than 15,000 hours. In Dumfries and Galloway, the Barcloy Mill Burn, which is one of the newly-monitored sites, received almost 3,500 spills.
Groups Watch Water Quality
Local groups continue to monitor the long-term effects of these discharges on water quality. Ruth Plevin, a member of the River Almond Action Group, expressed concern regarding the invisible pollutants often associated with sewage overflows.
Plans for Network Upgrades
Scottish Water maintains that 99% of the material released during these events consists of rainwater, surface water, road run-off, “grey” water from households, infiltration of groundwater, and trade effluent.
Simon Parsons, of Scottish Water, said that the expanded monitoring network is essential for identifying where infrastructure improvements are needed. He added that the utility aims to reach 100% monitoring coverage over the next five to six years.