Assume for a moment there is actually not enough water for everyone. Then you have to allocate the water by triage. Or you can let people fight water wars. Or let the free market price them out.
In fact, there is enough water for everyone. Even if we had to get all our water from desalinisation of sea water we could do it, it would just be horrendously expensive. And water would have a price. Again, access to water would be guaranteed through redistributive policies. Can the last politician to go out the revolving door please turn the lights off?
The problem is that like other commons, water is perceived as nearly free and overused. As long as ownership of water recources remains public and a minimum ration is guaranteed (either through actual rationing or through rebates, or a minimum exempt from charging) there's nothing wrong with charging people a "market" price for water.
Historically, that isn't what happens in Europe. Firstly there's no such thing as a market price because water companies are effectively monopolies. I'm not allowed to sell rainwater that falls on my house, or dig a well, because all of that water is owned by the local water utility. And there is no other water utility that I'm allowed to use.
Secondly during periods of drought European governments switch to rationing very quickly. In 1976 in some parts of the UK the mains were turned off, bowsers appeared in the streets, and people brought buckets. During an extended drought, people would soon get used to that. They might even get used to it permanently.
Almost everyone would rather put up with rationing than with being priced out of the market.
People would, corporations wouldn't. Can the last politician to go out the revolving door please turn the lights off?
I'm not allowed to sell rainwater that falls on my house ...
Are you allowed to collect it for your own use?
