Constantly urinating in the doorway - what can I do now?

Hi folks,
I've registered to this site to ask a question about my two year old female cat.

While she's always been a bit of a loner, we've been having a very serious problem: she is constantly urinating in the doorway. We've had to throw out several welcome mats and we are now cleaning the doorway several times a day. It's a ceramic floor and it's starting to create quite a problem with the grout.

A few months ago, we had her tested and we were informed that she had stones, which we've treated with a prescription and special dissolving food that costs quite a bit. We're now also giving her a special food to prevent further problems.

I thought the problem may have been from the litter box, so I kept it clean. After recommendation from a pet store owner, I've also moved the litter box in the doorway in the hope that she would use it rather than the floor, but to no avail. We've also been cleaning the floor thoroughly to prevent bacteria and odors. She seems to stay away for a day or two when that happens.

We have two cats: the problematic two year old female, and a three year old female who we have no issues with.

If the cat doesn't urinate in the doorway, she seems to also like to do in small, enclosed areas like behind the TV and under tables, but that seems to have ceased recently.

Both cats are fixed, and there are two litter boxes.

What can I do? I'm on the brink of giving her away if this does not get resolved, but my girlfriend loves her.

[EDIT] I completely missed the thread about this issue. I will go over it in depth and see what more I can do.

[EDIT 2] Whoops, I'm guilty of a few things from that thread. I installed a citrus (lemon) smelling air freshener in the cat room, so I'll remove that. I'll take the tops off and buy new litter boxes and keep them as clean as possible. Hopefully, that will help.

You might also want to take her back to the vet to be sure the treatment has been 100% effective, if the stones led to infection the first round of antibiotics does not always knock it out.

What are you using to clean the area? If any scent remains then she will go back to it. The enzymatic cleaners are usually the best, I use Stinkfree because it's availiable locally, but there are several others good ones on the market.

That it's the doorway has me wondering if there is/has been a stray cat outside the door who sprays your porch at night. It could be a territorial thing too.

You cat may associate the pain from the stones with her boxes. It's fairly common and you'll need to retrain her to the box. You can do that in a few ways. With my own cat, I had great results putting a little dish with treats in the far corner of a box (the box has to be in a corner of the room for it to work.) He'd climb in to get his treats and soon forgot about the pain. You can also use Cat Attract litter. It really works quite well.

Be sure you're cleaning the areas where your cat has urinated with something like an enzymatic cleaner, or I use just plain old vinegar. Even if you can't smell the old urine your cat might and as long as she does she'll go back to that spot. I like this site: http://www.vinegartips.com/cleaning/ as it can give you lots of tips including one for cleaning grout which is important since it's a porous surface and may be holding more odors.

My Molasses is a marker, he doesn't like it when he sees other cats outside, so his favorite spot is also the front doors, windows. He also does it in other areas, I use the enzyme cleaners. I also found that the Feliway Diffuser helps to calm him down a lot. Unless your little guy has a UTI. Then he might need a round of antibiotics. I also have a cat that has chronic UTI's, though the doorway sounds more territorial. Good luck.

I'm assuming you are using an enzymatic cleaner in the doorway? normal cleaners won't work. Is it possible to lock her up in another room with the litter box to see if that will work.

Also, get her rechecked to make sure the UTI is 100% cleared up. When Cello get's UTI's sometimes it takes 2-3 courses of antibiotics to cure him, annoying, but that's life! He pee's in the closet until it's cleared up, usually I don't even have to get him tested inbetween courses, I know if he stops peeing in the closet it's cleared up (I always get him checked anyways)

Try switching the litter to Cat Attract to see if that draws her back to the box.

I have a chronic bladder issue boy who for a while would urinate on cold surfaces - ceramic tile, ceramic food bowls, porcelain sinks, bathtub, etc. Our theory was that the cool surface somehow relieved the pain he was experiencing while urinating. We had him back to the vet for retesting and found out that his condition came back. And it took a number of changes to his food, medications and stress levels to get his problem under relative control. When I find pee on a cold surface, I know he has relapsed. Cat Attract has helped me retrain him to the litter box, as he was afraid of using it for a while - they start to associate the litter box with pain and avoid it. At one point my vet suggested that I put ceramic tiles in the bottom of the litter box with just a little bit of litter on top. Be creative with this.

So I agree with the other posters that suggested a vet recheck.

Didn't expect so many replies, thank you, folks. Following your suggestions, I've picked up two new topless litter boxes and an enzyme-based cleaner yesterday. I've also removed the citrus air-freshener from the litter room.

I'll also try the Attract litter if these options fail.

Again, thank you! Your replies are greatly appreciated!
[EDIT] Oh, and I'll do my best to bring her back to the vet as soon as I can.