Sometimes out of the blue a cat will stop using the litter tray. Most owners just think "Oh, an accident!" and clear up. Then it happens again…. And again.
ACT NOW. Cats learn to feel a certain substance under their feet. For most cats this will be the litter, itself. But if (for some other reason) the cat has not been using the litter, it will start getting used to the feel of, say, carpet. And once carpet becomes the substance which triggers urination or defecation, you are in trouble.
It's no good hoping the cat will change its behaviour. You have to change the environment!!
You have to work your way through ALL of these possibilities since you can't ask the cat what is wrong with the existing set up. So try the most likely and if this doesn't work, try the unlikely. What is unlikely to you may make perfect sense to your cat.
Sometimes a cat who has been happy with the existing set up changes his mind. For example a cat that has been happy to share a litter tray with his companion cat now refuses to share. Or a cat that was happy to pee and poo in the same tray changes his mind. Do not assume that because yesterday's set up was OK, it still is!
So all "accidents" with litter need quick investigation and quick remedy. Do not use disinfectants in cleaning up. Disinfectant smells may prompt the cat to use the same site again. Use biological washing liquid followed by scrubbing with surgical spirit. Cats urinate on existing urination sites, so cleaning up thoroughly is very, very important. Do not skimp this.
If none of this works, you have an emotional problem! So get back to me and I will send the next lot of info. It is also on my website www.celiahaddon.co.uk
If that doesn't help, get a cat behaviour counsellor.

1. DO YOU HAVE A LITTER TRAY? If you don't, you must install one NOW. It's no good expecting a cat to lead its life according to your standards. A cat that is urinating/defecating in the house may be afraid of doing it outside. So install a tray now.

2. IS THE CAT SUFFERING FROM INJURY OR MUSCLE STRAIN OR ARTHRITIS? Get this checked. If so, it may not be able to reach the litter tray in time or be unable to cope with stairs etc. Install extra litter trays in appropriate places it can reach. This may mean trays upstairs as well as downstairs, for instance, or not in rooms with slippery floors.

3. IS THE LITTER CLEAN ENOUGH? It must be cleaned daily, or better still twice a day. The cat may leave its bottom over the side because it doesn't feel the box is clean enough. Some cats will tolerate a dirty tray. Others will refuse to use a tray that already has one lot of dirty material. So, if you can't clean twice a day, see if adding a second tray will solve the problem.

4. IS IT TOO CLEAN? Are you putting in deodorants, disinfectants or scented litter. A litter tray should be dry and clean but with an aroma of urine and faeces - it should smell like a latrine. If you are cleaning the tray with disinfectants (not cloudy ones which are poisonous) remember to rinse it thoroughly so their scent disappears.

5. IS THERE ENOUGH LITTER? There should also be enough litter - some cats will stop using the tray if you are too mean with the litter. Put in more.

6. HAVE YOU CHANGED THE TYPE OF LITTER? Change back. If you want to change it, start by adding one handful of the new litter, then two - slowly changing over several weeks.

7. IS IT THE RIGHT LITTER? An outdoor cat may not like commercial litter. Try sand or earth. Then slowly change once the tray is being used. (see above). In general cats prefer thin-grained litter to large grained. I recommend Premium litter which comes in plastic containers and is expensive. But it clumps well and works out not too expensive because of that.

8. IS THE LOCATION RIGHT? Cats don't like going where there is a busy thoroughfare. Nor do they like going too close to food bowls or beds. A secluded place like a utility room, under stairs, etc. They don't like being overlooked by cats outside - ie if the litter tray is too close to patio doors where outside cats can look in. If you are not sure, install another tray in a different location and if the cat uses this one instead, get rid of the other.

9. HAS YOUR CAT HAD AN UNHAPPY EXPERIENCE WHILE ON THE TRAY? Has your cat had an unhappy experience while using the tray - ambush by a companion cat, ambush by a dog, pain, stomach pains while eliminating (from diarrhoea?), human interference while using the tray, a sudden loud noise while on the tray, pain from cystitis, recent illness of any kind, recent trip to vet for something which seems unconnected with litter tray pain but might be. If so, the cat may mistakenly decide that the tray isn't safe any more or the tray caused the pain. Therefore, experiment with a new (yes, new- don't be mean - you can use a baking dish if you don't want to shell out) tray.

10. IS YOUR CAT USED TO DOING IT OUT OF DOORS? For an outdoor cat (whom you want to be an indoor going cat) transfer some soil/sand from where they go. The familiar smell may trigger use. Some cats will use potting compost or peat, rather than other litters. Add some soiled material so the tray smells like a latrine. This is worth trying even if your cat has used litter in the past - it doesn't cost much to put some soil in a tray.

11. IS IT THE RIGHT LITTER TRAY? If the problem is that the cat won't use the litter tray (and therefore goes elsewhere) check that the cat is happy with this particular litter tray. Try putting down another one or some kind of temporary "tray" to see if a different one would be more acceptable. If the new litter tray is unused, maybe transfer some material from the place the cat does go, into the box.

12. DOES YOUR CAT DISLIKE USING THE SAME TRAY FOR BOTH URINATION AND DEFECATION? Add a new tray so that it can urinate in one and defecate in the other. Odd but some cats definitely prefer this. Some cats that were OK about peeing and pooing in the same place change their minds about it. Just putting two trays side by side may not work. Cats may want two separate locations.

13. ARE TOO MANY CATS USING THE SAME TRAY? There should be one litter tray per cat as a minimum and trays should not be side by side. Some cats won't go in the same place with other cats. A tray for each cat and one over makes extra sure. A new cat, which was occasionally urinating upstairs outside the tray stopped doing this when an upstairs tray was installed, as well as a downstairs one. Always worth trying an extra tray - just in case. Place it in a different location to the others.

14. IS THE CAT AMBUSHED WHILE ON THE TRAY. In a multi-cat household a bullied cat may be being ambushed while on the tray. Add trays where the cat can reach them without having to pass through enemy territory.

15. DOES THE CAT NEED A COVERED TRAY? Experiment with a cardboard box, one that fits tightly over the litter tray as a cover. If this helps, then buy a litter box with fitted cover. Use the same kind of litter and place some of the soiled litter in the new box, just so that it smells right to her. Some cats prefer see-through hooded trays to opaque ones, particularly in multi cat households. Some prefer opaque hoods.

16. IS YOUR CAT FINDING IT DIFFICULT TO CLIMB IN? Arthritic, elderly or injured cats may need a shallow tray. Arthritic cats, like arthritic humans, need pain relief. Some garden centre/DIY shops stock bases designed for holding plant pots/grow bags: they come in a range of sizes and there quite large rectangular ones with solid bases that hold several large plant pots, and the rims are about 1" high.

17. DOES YOUR CAT HAVE CYSTITIS? Symptoms include straining, pain when urinating, blood in urine, frequent urination, urinating in the wrong place, lots of tiny urinations instead of several large ones. More common in long haired, overweight, neutered males. Check with vet. Cystitis attacks occur at stressful times.

18. IS YOUR CAT HANGING HER BOTTOM OVER THE SIDE OF THE TRAY? Make sure the tray is full enough and clean enough. Even so some cats dig furiously but leave the backside out of the tray!! Try placing a smaller tray inside a larger one with a gap of about two and a half inches at the entrance. This ensures that the cat has to step across the gap to enter and use the inner try. Any overspill is absorbed by a small amount of litter in the gap area. The other idea is simply to buy a large deep round washing up bowl and use it instead of the conventional litter tray. "Our cat, Mitzi, was unable to get her tail over the side. It had other advantages in that the bowl was easier to lift with its rounded rim and easier to keep clean" reported Mitzi's owner.

There's a product, Vetzyme Shift-it, which 'freeze' animal faeces so that it can be more easily picked up
Consult www.fabcats.org for Spraying and Soiling indoors or send an s.a.e. with small donation to Feline Advisory Bureau, Taeselbury, High St, Tisbury, SP3 6LD.