Kitten won’t pee in litter box

[Slynne10]

I have an almost 4 month old kitten and she is having “accidents” daily and I’m looking for recommendations on what I can try. Sorry for the long post but really need to do something that I haven’t tried.
When I got her I placed a litter box downstairs and one up. She would use it most of the time (always peed inside) but occasionally pooped outside of it. Switched litter and it seemed to help for a few weeks. Then she started not using the downstairs box and only the upstairs. She also started backing up to pee and occasionally went over the side so I got a covered box. She would not go in with the door flap on it so I removed the door. A few times she turned around while in the box and peed out of the door opening. Then I was cleaning the box, the lid was sitting on the floor next to it and she ran in and sprayed in it. Since then she has pretty much only peed on the floor right outside of the box, but always poops inside. I have tried different litter and even put two litter boxes side by side to give her an option. And I always clean up after her almost immediately and use an enzyme and odor remover. Also, she has seen a vet and is healthy.

 

[iPappy]

Hi! Does your kitten have access to the entire house all day and all night?

 

[Slynne10]

Hi! Does your kitten have access to the entire house all day and all night?

Yes. It is not a large house. 3 bdrm with basement. 2 litter boxes up and one down.

 

[FeebysOwner]

Hi. Is she spayed? Just thought we should make sure. If not, that could be the problem. Otherwise, I would try larger litter boxes, since pretty much everything else you have tried has failed.

I presume she is peeing outside of the box(es) with the two that are upstairs? Does she use the downstairs box at all?

 

[hololark]

There's a few things you can try. Hope one of these help.
First, try Dr. Elsey's Kitten Attract litter. I've seen it convince 13yr old alley cats to use the box. It's pretty good stuff.
Second, if she won't pee in the box then that means there's something she doesn't like about it. Cats are super dramatic about everything. It could be something as small as her not liking the depth of the litter to her not like the location of the box. She might be associating the box to pain or fear. Is there anything near the boxes like washing machines, a broom that fell once, a poster of a racoon? We had one cat that would ambush the other cat while they were using the box. The naughty one was separated and stopped but the first one held that grudge for a year even though it only happened a few times.
Third, if she's really young, she might not know how to use the box. They typically figure it out just instintually, but you might try showing her how fun it is to dig in the litter.
Fourth, use positive reinforcement. Telling a cat "no" or that they've ever done anything wrong in their entire life, has never worked on any cat in the entire history of cats. They refuse to recognize the word no. So instead, if she uses the box, give her a treat. That way she'll associate the box with getting things she wants. If you punish her or yell, she's going to associate the box with fear and double down on the behavior.
Fifth, if it's in a closet or corner, she may not like the lighting. Some want the area dark for modesty and others want the lights on so they can see if anyone is around.
Six, The wall plug "happy pheromones" feleway stuff might help. I've tried it for other issues. I have no proof of it working or not working but the vets seem to like encouraging it.
Lastly, get another kitten and hope that it sets a good example for her. If she sees the other kitten using the boxes correctly, she might be convinced it's a good idea. Generally, cats need another cat around anyway.

Sorry that's long. I really feel for you though. Good luck!