I dont want to speak directly for the person you are replying to, but I think the point they are trying to make is this. Government exists for lots of reasons. If government has to spend more money to provide fresh water of the people (as it should if needed), it costs more. To cover the costs, there are two direct resources. Higher taxes or taking funds from elsewhere. Higher taxes would also mean less funds to draw from for other projects.

And I dont think it is to be taken in an anti-tax way, but a statement on resource allocation. If water becomes expensive for the people and government needs to subsidize or up subsidies, is there a risk that infrastructure for bridges get ignored to keep taxes low? Or to not tax people into poverty. Of course we can offset this with closing loop holes and upping taxes on the higher brackets.