About a year after we got her, my cat started peeing outside the box (but not all the time -- she will pee and poop in the box most of the time, she just seems to prefer certain carpet spots). She was peeing in my room in the same spot until we put those plastic spiky things over it. She would pee on the stairs until we covered them with cardboard (she won't pee on the cardboard). It seemed like the issue got better until she started peeing in the hallway.
I feel like we've tried everything. We've taken her to the vet so many times -- they did a urinalysis and an ultrasound and everything's fine there. She's on anti anxiety meds. We have six litter boxes for two cats, three on each floor of the house. It's not an access issue or not being able to hold it, she's seeking out these spots and it's like every time we cover one she moves to another. We put her food bowl over her hallway spot and she just started peeing next to the food bowl.
She‘s spayed and has been for a while. She's not having issues with our other cat, either. I don't know why she's doing this or how to fix it but my family is talking about giving her back to the humane society. I really, really don't want to do that. She's my girl and I don't want to lose her but also I know it's really hard for cats surrendered due to litter box issues to get adopted again and I don't want her to be alone forever. Please help.