It's a sad situation, but it's an infrastructure problem. Take my village for example. There's a pumping station at the bottom of the shallow valley that takes our sewage, and some from another station nearby, and pumps it over a hill to discharge, presumably, into a main sewer for onward treatment. In the seven years I've lived here the pipes from the station have fractured twice causing raw sewage to literally leak out of the middle of a field and run into the local water course. The same thing happened to the other pumping station feeding this one, although they did replace the pipes eventually. On at least 5 occasions the pipes have been blocked and the station overflows into the local stream. I say 5, because I reported them after seeing it while walking the dogs, so I've no idea how often it actually happened. During the heavy downpour a couple of months ago the station couldn't cope with the amount of excess rainwater flooding into it and again overflowed. When reported it was placed in a queue to get looked at 3 days later.
We're next door to Milton Keynes. As a new town they wisely kept all rainwater and sewage drainage completely separate but anywhere else is going to have them all combined still, I believe. This is why London is having to invest in the tideway tunnel.
I'm currently looking at a gash in the road outside my house that has been leaking a constant stream of water for several months now. A succession of Anglian Water people have come and pointed at it, tested it, decided it wasn't chlorinated, then it was, then disappeared again. I'm waiting for it to freeze over in winter and someone to get hurt before something is done about it.
The bill and disruption required for fixing this is enormous, nobody wants to add it to their taxes or water bills. Climate change is going to make the storm overflow situation potentially more frequent. The Tories appear to have just said that that's the way it is and shall ever be.