First time publication of overflow data shows monitoring progress and scale of spills

The first public release of storm overflow data by the Environment Agency (EA) last week showed both huge progress being made by the water industry on monitoring spills, but also that overflows are being extensively used and with significant variance between water companies.

The Event Duration Monitoring data (see table for a summary) detailed that around 80% of the industry’s 14,630 overflows are now monitored, a steep increase on 2019 and over the past five years. Water companies are targeting 100% coverage by 2023, and investing £1.1bn this AMP on improvements.

The better data, which is used to target investment and planning, exposed that sewage and stormwater was discharged around 400,000 times, for more than 3m hours during 2020.

The Rivers Trust welcomed the publication and increased monitoring, but called for actions including:

• real-time monitoring of overflows discharging more than 20 times a year and

• accelerated investment in fixing overflows and the upstream problems that cause them to spill more frequently than they should – “Water companies have committed to investigating and improving 800 overflows before 2025 at a cost of £1.1 billion – this will deal with only 5% of the 14,000+ SOs that are declared by water companies,” said director for partnerships and communications, Christine Colvin; and

• citizens to report unmapped overflows (in addition to the 14,630 identified) to water companies and the EA.

A spokesperson for Water UK emphasised the industry’s commitment to addressing the issues, but also called on others to play their part: “What we all want to see are improvements in the health of our rivers. Storm overflows account for only around 4% of all the reasons for rivers and waterways not achieving good ecological status, so it’s essential to deal with all the other sources of harm, and all sectors involved will need to play a part in addressing this complex challenge together.”

The EA noted storm overflow data has always been available by information request, but following the commitment made by the Storm Overflows Taskforce to increase the transparency and accessibility of this data, annual data is now available on GOV.UK.