Increasingly hot Europe faces more Severe Droughts and Growing Challenges for Water and Land Management

I have wondered if when you use water would make a big difference or not. I could get a large tank and fill it up when water is more abundant then use it during drought.

But that will cost me the price and space of a big tank with absolutely no benefit for it. I can just use the tap water during the drought instead, costs the same regardless of when I use it.