Way too late to the party, but when my dog is thirsty, she finds a bathtub and stands in it.

This started when she was a puppy, I was living in a condo with no AC, and, as a husky puppy, I was worried about her overheating. According to Google, the best way to keep a dog cool is to wet their paws (dogs sweat through their paws), so for most of that (very hot) summer I kept a couple of inches of (fresh) water in the tub.

Now we'll be visiting, and I'll sometimes forget to put out water for her, so she'll go find a random tub. If I don't notice, she'll let out a little yelp so I find her (but usually I hear her getting into it). People have noticed. They think she's nuts, but it works.