Just to show the other side of this argument - sewer overflows are often a necessary and regulated part of a combined sewer network. The reality is that the majority of the Victorian infrastructure all companies have to run is a combined network, meaning sewage and road drainage, surface water, roof drainage etc flow through the one pipe to treatment. This has a number of disadvantages, the main two being that a lot of clean water is taken to treatment and where the system gets overwhelmed in times of heavy rain, the overflows legally operate and discharge dilute but yes, untreated, sewage.
The rain can’t be controlled, and building bigger pipes only takes you so far. Imagine a tank being filled up, eventually there will be a storm that beats that tank and makes it overflow. The only way to remove overflows completely is to separate foul sewage and surface water, meaning that all your waste water goes in one pipe, and all the surface water, road and roof drainage goes into another. This already happens in new developments and has been happening for decades, but the reality of replacing all current sewers with this is hundreds of billions of pounds of investment, not to mention never ending roadworks and construction, rising bills and in some very congested cities a total inability to do so as the underground pipe and utility network is already majorly congested. Without overflows in networks like this, that discharge can end up in people’s homes and gardens.
There are of course situations where overflows operate when they shouldn’t - due to blockages, bad practice, lack of maintenance. I’d much rather see legislation to help with that side of things - putting more responsibility on companies (and customers!) to protect the environment. I’m not for a second saying that overflows are a good thing - in an ideal world we wouldn’t need them. But we are so very very far from that ideal it’s disingenuous to pretend otherwise.