Heavy rains are often followed by sewage works overflowing into rivers and the sea in the UK.
Wessex water told me the cause is older infrasture where the “black” water and surface water travel together.
A simple change to make that has other benifits is for households to put a rain garden between their gutter and the drain.
Heavy rains could then be soaked into the ground to help gardens grow and the system is releived of the peak flow.
A guide on building rain gardens is in the works.
We will talk to water companies to see if they could make incentives for this kind of intervention.