Thank you, Heidi and Randi. I decided it was Galaxy, because it would be so hard for Sparkler to haul herself up onto the bed to begin with, and if she had done that, it would have been next to impossible to get herself into position to do those particular puddles.

Yesterday because I had them shut out of the bedroom, there were no further samples on the bed, but I didn't know if there would have been one if the bed was available. Galaxy does drink from the water bowl fairly often, and she does little pees in one of the litter boxes fairly often.

We went to see the vet this morning and have this checked out further. She does not have a UTI. They are checking out other possibilities, including diabetes.

Since we got home, about 11:30 am, I've left the bedroom door open with the shower curtain on the bed. No pee on that so far!