- The number of storm overflow spills reduced in 2025 – down from 40,792 spills in 2024 to 27,776 in 2025.
- Data for 2025 shows that spills from storm overflows have decreased by 31% over the past year.
- Duration of spills has also reduced by 49%.
Spills from storm overflows have reduced by almost a third across the North East.
New data from the Environment Agency shows that the number of storm overflows discharging in the region has reduced by over 13,000 spills (31%) in 2025.
The Event Duration Monitoring report, published by the EA, shows that the average number of spills per overflow has dropped from 26.3 to 17.8 in the last year, and that the total duration of spills has also seen a reduction of 49%.
Although 2025 was a drier than average year, the reductions are also shown to be because of action taken by the water company over the last 12 months.
Action includes finding and fixing infiltration to the highest spilling storm overflows, disconnecting unwanted drains from the networks, adding new and increasing existing storage in key areas, repairing manhole chambers and stopping rain and groundwater from leaking into sewers.
Northumbrian Water have invested £80m to reduce the use of storm overflows and to upgrade the wastewater network between 2020 and 2025 – with a further £1.7 billion to be invested in a massive environmental program between 2025 to 2030.
As well as this, the water company has invested £20m in smart sewers – which involved connecting over 800 sensors and sections of network to Smart Sewers in the Tyneside area, using the technology for the first time in real life and world conditions.
It uses AI and sensors to help move wastewater around the networks of pipes in real time to balance flows over a greater area – helping to reduce the risk of needing to use a storm over spill to relieve the network.
It is a UK-first project, the largest of its kind anywhere in the world and uses a combination of new technology, sensors and AI analytics to lower the risk of overflows needing to happen.
Last year, the trials of smart sewers saw a reduction of spills by 30% at Howdon Sewage Treatment Works, in North Tyneside.
Richard Warneford, Wastewater Director at Northumbrian Water, said: “These results show positive progress, and although the incredibly dry weather we saw last year has no doubt impacted these figures, our investment and the hard work done by our operational teams throughout the year has clearly made a difference too.
“We know there is still a long way to go, and a lot more work to be done. Storm overflow use is something that our customers care deeply about and will remain a real priority for us going forward.”