You've mentioned that "you totally control how much water she gets": Not a good idea, as this can CAUSE a urinary tract infection. I'm speaking from experience, unfortunately. Instead of controlling water intake, I now PUSH water by adding it to my dogs' food to ensure they get enough. I also strip test for Fanconi AND UTI's etc. monthly with test strips or whenever I'm concerned that one of my dogs might have a problem, as they're older & special needs.
VET-10 strips from Teco Diagnostics check for glucose, blood in urine, specific gravity, urine alkalinity and a number of other simple indicators of problems. They're the same test my vet uses, in fact she suggested I get them to help determine if I need to make an appointment–sometimes it's hard to tell if a young Basenji is peeing in the house because it's raining outside, or if an older dog is incontinent due to age or another factor like Cushings or a bladder infection. They're not to replace your vet, but they CAN tell you if there's an obvious problem.