I have done this process for when desal plants were hit in another Gulf country. And there was not much info, but lets try it for Kuwait.
Does the US have it's own desal plants in Kuwait ? And it appears not.
"Camp Buehring, a United States military base nestled in northern Kuwait just 20 miles from the Iraqi border, faces a challenge: there are no wells, rivers or other easily accessible sources of water.In this arid region, water is a precious commodity. Soldiers rely on trucks to deliver the water they need for showers, drinking and flushing toilets"
So for that base anyway, it is trucked in. The article goes on : "“They have to bring in all their water,” said Jeremiah Gilbert, a distributed energy power systems engineer at the Idaho National Laboratory (INL). “It can get really expensive, so we wanted to look at ways they could recycle water. "
So for that base, they need to truck it in, and it is expensive. I would say that is a pretty good indicator that the US is using civvie water at that base. Source for that is an article from last year from the Idaho National lab.
Water resiliency at Camp Buehring: INL's innovative water reclamation system - Idaho National Laboratory
Now in my book, if the US military has a base in such an arid place, and it does not want to be "embedded" in anyway shape or form, then they should have their own desal plant, or water source.
There is also a France 24 article from yesterday. And see what Iran says :
"Tehran justifies these attacks by citing the US military presence in the country. With some 13,000 American troops on its soil, Kuwait hosts one of the largest US contingents in the region."
Why Iran is targeting Kuwait's desalination plants as part of its war strategy - France 24
Yes. Hitting desal plants is not good. But look at it objectively. If Iran want to get US forces out of Kuwait, then from a military point of view, their action makes sense. This is asymmetric warfare after all.
And no, this is not me defending Iran, this is me explaining why what they are doing makes sense. Denying resources from enemy forces is as old as war itself.