Just focus on these issues if you want to stop cat urinating outside litter tray.
Do you have the same litter tray for multiple pets? Cats are very concerned and serious about their private habits. They will spend hours licking their body cleaning themselves. You will never find a dirty cat that stays dirty for long.
In such a scenario, if you find that you are struggling to stop cat urinating outside litter tray, chances are high that the pet cat is disgusted at the condition in which the litter tray has been kept. If you do not change the litter tray very regularly, then it is obvious that the odor of urine and elimination will be present in the tray permanently.
This is no different than asking any individual to walk into a public urinal that has not been cleaned and aired properly. The person will prefer urinating out in the open rather than in such unhygienic conditions. That is exactly how your cat feels. If you want to stop elimination outside litter tray, you should clean the litter tray on a regular basis.
Of course, if you have multiple cats in the house and if you have one or a few litter trays, this problem is only going to become more acute. You can simply make use of multiple litter trays and assign one for each cat to solve the problem. It is advisable to have more than one litter tray per cat to avoid this problem. If all the cats like the same brand of litter, then you should not have any problem at all.
If you want to stop this bad habit, you should reinforce the message again and again. If the pet uses a specific litter tray, it should be rewarded and praised. On the other hand, if some other cat uses the same litter tray, it should be criticized. Of course, you need not go ballistic just to express your displeasure. You just have to express the displeasure by praising the other cat and cuddling it and ignoring the errant cat. This will automatically send the message that the errant cat has made a mistake. Peer pressure and jealousy will automatically stop cat urinating outside litter tray.
If the problem still persists, you should be aware that they may be medical issues involved. This may be causing the problem. In such a scenario, you should contact the vet if you are not in a position to stop cat urinating outside litter tray despite your best efforts.