Maybe you should get a Ken & Barbie doll and use them to act out a scenario about the water being cut off but Ken, who wisely prepares for such occurrances, has saved the day with the supplies he had stored in the garage. MAYBE, she'll get it then.

My wife and I just went through the same thing (the water didn't get cut-off), and her attitude was "oh well" because she knows what we have stored and she does get it. (she use to play with 2 Barbie dolls and named our oldest daughter after one of them; no,,,it was a different name than "Barbie", thank-God)