The thing is, this is such a massive political own goal for the Tories and they don't even know it.

Water quality sounds like a bit of a niche political issue. But you know all those rural southern 'Blue Wall' constituencies where the Tories have been bleeding votes to the Lib Dems over the last few years? Water quality and sewage discharge into rivers comes up as a top local issue for voters in so many of these places. This is why the Lib Dems are campaigning so furiously on water quality in their rural target seats. It's also why every time there's a national news story about water quality (like this one), there's always a quote from a Lib Dem spokesperson in the article rather than a Labour quote (even though in general, the national press massively prefer to look to Labour for an opposition quote).

The Lib Dems have identified this as a salient issue that the Tories nationally simply haven't woken up to. It's such an damning statement about Rishi's Tories - not just clueless about what's happening in the country at large, but clueless about even the parts of the country that have Tory MPs - so clueless that they're making national decisions that are actively harming their own election prospects but are clearly unaware of the impact this is having.