Here is a previous post that you may find helpful. Though it's addressing the issue of peeing outside the box, the steps to correct pooping outside the box are the same. Make sure there's not a medical problem, reduce stress, provide positive reinforcement, clean any soiled things or areas with enzyme cleaner, add at least one more box, use Cat Attract Litter, cover soiled areas with something to discourage kitty from using the same area (after cleaning with enzyme cleaner) - if it's roughly in the same location every time, move the litter box there, and then slowly move it back to where you want it.
Originally Posted by LDG
I feel your pain.
Been there ourselves.
The first time we had a problem with Spooky, what we did was
1) buy the plug-in diffusers,
2) added Cat Attract to the litter (I don't think the Cat Attract Litter existed as such yet),
3) gave Spooky 10 - 15 minutes of extra play time both morning and evening.
4) We purchased Multicat Household Harmony flower essences - I think you should try the Calm & Serene flower essences (available here: http://www.catfaeries.com
5) That same site sells large quantity Anti-Icky Poo enzyme cleaner. It may work better than what you've been using. And with a gallon bottle, you can shake it up and pour it on the cushions and in the cracks of the couch. We used about half a gallon each application. If urine can get down there, another liquid can get down there. On our couch with the attached cushions, we purchased Nok-Out (http://www.nokout.com
). It is safe for animals and leaves your couch smelling slightly like bleach. We had to apply it three times before the smell went completely away. It took at least a week to dry with each application - though it was summer and more humid. We covered the cushions with aluminum foil and kept a throw blanket handy. When we wanted to sit on the couch, we put the throw blanket down over the foil and sat on it like that, and we folded it up and set it on the mantle when we weren't using it - but this way it doesn't matter how long it takes to dry.
6) We also set the litterbox on the couch with the cat attract additive on the litter when we weren't using the couch. Then we set it on the floor in front of the couch. Then we set it next to the couch. Then we moved it about a foot a day until it was where we wanted it.
7) Thankfully Spooky only peed on the end of the mattress (where are feet are). But it doesn't much matter - we poured about 1/2 a gallon of Nok-Out in the area, covered it with thick towels, and then made the bed. We changed the thick towels under the sheets every day for three days - it was dry enough on the top of the mattress to just leave a thick towel in that spot after that. We placed a litter box on the bed over where she peed when we weren't using the bed - when we were, we placed it on the floor at the foot of the bed. Then we did the same thing there - we moved the box about a foot a day (with the cat attract additive in the box) until it was back where we wanted it (in the hallway outside the bedroom). Thankfully the mattress didn't need another application after that.
If you have two litter boxes, I'd consider adding a third - and perhaps do try one with out a cover. With your covered ones, if you have the swinging doors on them, consider taking the swinging door off of one of them.
I know you live in a small apartment - but for two years we lived in an RV that was 8' wide by 37' long with five cats. We had 3 litter boxes, and I scooped probably 3x a day. It never smelled of kitty pee or poop unless kitty had just taken a stinky poop. We have several cats that don't do a good job of covering their business.
Also, have you purchased a black light to go through the house to make sure you've gotten all the spots?
The next step after all of that is confining her to a very large crate or small room. I know you don't want to do the litter box retraining because of her sister, so if you don't want to go that route, then you'd really have to consider an anti-anxiety medication.
The next time we had a problem with Spooky all this stuff didn't work. We used an anti-anxiety medication, Elavil (amitryptaline). Others recommend Buspar. Buspar you can just stop - Elavil you have to wean them off the med, you can't just stop giving it. We used it on Spooky for four months then weaned her off over a couple weeks. She slept a lot for the first three weeks on it, but the peeing outside the box stopped pretty much immediately. And once we weaned her off of it, it didn't start again.
A couple months ago she peed outside the box. I freaked - I thought it was happening again. But we took her to the vet - it turned out she had two teeth that were hurting her. They needed to be pulled. When she came home - no more peeing outside the box. So it was just her way of letting us know she was in pain. *phew*
All of that said:
1) Are you certain your cat does not have a medical problem - even if it not a UTI, is it possible your kitty is in pain? Bad tooth? IBS? Your kitty should go to a vet. 85% of the time, when a cat pees or poops outside of the box when they previously used it, it is a medical problem. However - you're right. This does sound like a likely candidate for a stress-related issue, though pooping outside the box is sometimes . She is spayed? If not, she should be.
2) Feliway is a synthetic hormone that mimics the "friendly" markers in cats' cheeks. It helps reduce stress (even if you can't see any reason for kitty to be stressed). There are plug-ins (like air freshener we can't smell) or spray bottles. If you use a spray bottle, spray it around the house at cat height (especially around where she's been peeing that she shouldn't) and don't spray it near scratching posts or litter boxes.
3) You MUST use an enzyme cleanser to clean up cat pee or poop. Anything else may make it smell OK to a human nose - but not to a cat nose. The area must be drenched - if on carpet - down to the floor boards. If on a couch, through the cushions. It should take DAYS to dry. And add it to the laundry of whatever you're washing that she peed or pooped on.
5) Some bathroom rugs ARE a problem because of the backing. Quite a few people have written about it, and we had one that encouraged Spooky to pee on it. Others have had rugs that they kitty poops on. Replace throw rugs with that rubber backing.
6) You only have one kitty - but with one cat, you should have two litter boxes. Try having one covered one (we always remove the swinging door) and one uncovered. Make sure they are in convenient low-traffic areas for her to use. PURCHASE "CAT ATTRACT" LITTER!!!! This really seems to help with problems like this.
So... make sure there isn't a medical problem and that she's not in pain. Have her spayed if she isn't. Use the enzyme cleaner - gallons of it, if necessary. Get the Feliway, the Calming Flower Essences, replace her litter with the Cat Attract Litter - and any time you see her use the litter box, praise her to high heaven and give her treats. The positive reinforcement combined with the stress reducers (including extra play time morning and evening) and the Cat Attract litter may do the trick.
If not - then you have to resort to litter box retraining. This means confining her to either a large dog crate or a small room. You have to make sure to spend lots of time in there so she doesn't stress from being alone. Our Spooky started obsessively licking, and we couldn't get her to stop - so we went with an anti-anxiety med.
As a very last resort, talk to your vet about an anti-anxiety medication.
Hope this helps,