Nearly EIGHT raw sewage spills a day across Bristol as top 10 worst-hit locations revealed

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Sewage spilled into Bristol’s waterways for more than 5,000 hours last year

Raw sewage spilled into Bristol’s waterways 2,806 times throughout 2022 - the equivalent of almost 8 a day. In total, sewage seeped into the city’s water network for a total duration of 5,383 hours.

Conversation experts, the Rivers Trust has compiled data from 190 of the 215 storm overflows across Bristol which shows how many spills occurred and the combined time sewage was discharged. Storm overflows operate automatically during or after intense rainfall to protect properties from flooding and are licensed by the Environment Agency. Once overwhelmed, sewage can seep out of the system into the waterway.

The Avonmouth Sewage Treatment Works (STW) overflow spilled for the longest duration of time - accounting for almost a fifth of the total hours. This sewage hotspot spilled 86 times throughout 2022 for 1080 hours. The sewage was discharged into the Severn Estuary which suffered the two longest overflow spills.

A table of the 10 worst affected areas for storm overflows is below:

Location of storm overflowTotal spillsTotal duration (hours)Discharged into (waterway)
Avonmouth STW861080Severn Estuary
Portbury Wharf STW99749Severn Estuary
Muller Road Cso105447Horfield Brook
The Portway Cso39254River Avon
Filton Avenue90204Horfield Brook
Lower Hanham Road41174River Avon
Plimsoll Statue38142River Avon
Ellesmere Road39139Brislington Brook
Portway Combined Sewer Overflow77126River Avon
West Town Road Pumping Station56103River Avon

The Rivers Trust map shows that storm overflow discharges in Bristol reduced from 2021 to 2022. In 2021, a total of 3,492 spills were accounted for with a duration totalling 7,144 hours. This data was extracted from fewer storm overflows with 171 of the city’s 215 being monitored.

A spokesperson for Wessex Water, which is responsible for the region, told BristolWorld: “Storm overflow discharges in the Wessex Water region significantly reduced in 2022, and this is down to dry weather as well as our £3 million a month investment in improvement schemes.

“In Bristol, we’re increasing the sewage treatment capacity at our largest water recycling centre in Avonmouth so we can deal with more rainwater. But clearly, there’s more to do and we’re committed to continuing to reduce the frequency of discharges, starting with those that operate most frequently or have any environmental impact.

“We’re also planning to go even further and, if approved by our regulators, will invest more than £9 million per month from 2025.”

To view the Rivers Trust interactive map, click here