There is no rule in terms of compensation.

You may have a look at this article listing most FT topics about no water issue.

https://thegatewithbriancohen.com/sh...-a-hotel-room/

You may write to the hotel to ask for a gesture and depending on the answer, contact CS.

And also, as this is the second incident you've experienced, from now on, would you mind keeping us posted about your upcoming hotel stays so that we can avoid staying there at the same time ?