Cat peeing on floor whenever we leave for a few days
Our cat uses the litter box faithfully except when we leave the house for a few days. We have someone to feed her and clean out the box while we are gone. When we come home she will have urinated on the bathroom floor a few times.
Assuming she's healthy, my guess is that it's a stress response. Perhaps it might help if someone she feels comfortable with came to stay with her full time while you're gone, rather than just coming in to feed her and clean the litter box.
If that's not an option, then I would try to keep her routine as close to normal as possible while you're gone. Is your sitter cleaning the box at the same time and with the same frequency and level of diligence as you?
Is she getting exercise, play time and mental stimulation while you're gone? It might help her to pass the time and also relieve some stress.
Another possibility is to try reducing her stress levels with any of the various products made for that purpose. They can be hit or miss, but you might find one that works. Some of these products are Feliway
(get the diffuser), Rescue Remedy, and some of Jackson Galaxy's herbal products.
In extreme cases, your veterinarian can evaluate her and possibly prescribe anti-anxiety medication, but I would not go that route unless absolutely necessary.
I hope that helps and please let us know how things go with her.