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Storm flooding


We maintain our sewer system to ensure it has sufficient capacity to cope with wet weather.

However there is a limit to how much additional capacity we can build to maintain its effectiveness.

As this means flooding can occur during extreme rainfall, we use a measure to identify the percentage of the population at risk of sewer flooding in a 1-in-50 year storm (equivalent to a 2% chance each year).

Unit of measurement

Current performance (21/2)

2025 target 

% of population at risk