another thing to think of, hard-won knowledge here, when selecting a storage area is to look at the lay of the land. see if they have provided enough slope for the rain to run off, away from the units. I have had a literal river run through the storage area I was using. also, though it probably isn't an issue in AZ, even humid air can cause moisture to wick through concrete, and it will come up through boxes or anything else sitting on it. use plastic or pallets to put your stuff on.
Thats a good idea! Thanks