Scottish Water expands sewage monitoring network to track overflow spills

Scottish Water installed over 1,000 new sewer monitors across Scotland in 2024, increasing the monitored portion of its network from 6% to 30%.

This expansion allowed the company to record more than 76,000 sewage spills that previously went uncounted. The data reveals that tens of thousands of spills occurred at various sites, including popular locations like Loch Lomond. The company states that the vast majority of these spills consist of rainwater and surface runoff rather than human waste.

These overflows act as relief valves to prevent the sewer system from flooding homes and streets during heavy rain. While the increased monitoring provides a clearer picture of how the network operates, the company notes that it is difficult to compare these new figures to previous years because the older data came from a much smaller set of monitored sites. The data identifies specific hotspots, such as the River Clyde in Glasgow, which received nearly 14,200 spills last year.

Local residents and campaigners expressed concerns about invisible pollutants like microplastics and pharmaceuticals. Meanwhile, some community members who test water quality independently reported that most samples still meet standards for recreational use. Scottish Water plans to reach 100% monitoring coverage over the next five to six years.