The amount of water used is somewhat less important than what the source of the water is.

And it's important to understand that "using water" isn't like "using coal". In other words, while coal can be burned once, water is in a cycle that means water can be "used" infinitly.

But back to the source. A golf course near me takes effluent water (ie treated sewerage) destined for pumping out to sea. They spread it over a large piece of land. What is not consumed by plants, or evaporation, ends up in an underground aquifer.

So it "uses" a lot of water. But it's not using tap water.

Obviously this is not true for all courses. Hence the issue of "source", not "quantity" is material.