About Rubi: if it’s a UTI or cystitis, the vet should be able to tell, either just by feeling her, or with a blood test. You may have to give her special expensive prescription cat food. Is there any blood in the urine? That’s usually a telltale sign of crystals. Otherwise, if she’s just trying to mark her territory, try using Feliway – spray it in the areas she’s been peeing in, and it somehow will calm her down and she won’t feel the urge to spray. It’s a little expensive, but worth it.