Looking ahead to the official release of storm overflow monitoring data Stuart Colville gives the industry perspective on the expected fall in spills.

• There were fewer overflow spills last year into rivers and seas, and the average spill was shorter
• The length of overflow spills reduced by a third, while the number of individual overflow spills fell by a fifth
• £3.1billion of work is happening up and down the country to cut spills

15,000 overflows were built into sewers between the 19^th century and the 1960s. Our forebears’ idea was that these would act as ‘relief valves’ during storms, allowing excess rainwater from drains to escape before pipes overloaded and flooded bathrooms. The concept was similar to an overflow in a sink.