EastMids - we might have enough (drinking quality) water right now, but the population is growing and we have to store enough of the stuff for dry periods.
If someone accidentally or deliberately contaminates a large reservoir, or there's a drop in expected rainfall (or rain falls in the wrong places), then we can easily run short in certain regions of the UK.
Your attitude is very common, sadly, and that makes it all the more likely that in the future vulnerable ppl might go short, or have to pay more if they are metered. (Nb I think we should all be metered. It would be fairer.)
Then there is also the energy 'cost' of checking the water is of a good standard to drink, piping it, and dealing with sewage which uses a lot of energy. (It doesn't just magically arrive from the rain clouds into your kitchen tap. There's a huge effort involved i supplying you.)
It's only a few generations ago since our ancestors had to fetch/carry water from a communal pump. So I am sure they didn't waste a lot.
We are so lucky there's no effort for us to open a tap and let the water flow, and where not metered, there's no extra cost for being profligate with water.
So, as it would be unthinkable to price water upwards to the point no-one would dare to waste any, better to try to educate the population re the preciousness of water/the efforts needed to supply us with a constant flow, and remind them that the wasting precious common resources, for no good reason, is selfish and anti-social?