Cats may urinate in other parts of the house because:
1) They have cystitis (a bladder infection)
2) They have litter aversion
3) They are afraid to use the litter tray because it is in a high-traffic area and they are frequently disturbed
4) Another cat has used the tray or another cat chases or otherwise intimidates them when they try to approach the tray
5) They are marking part of the house as their territory.
Urine may be sprayed from a standing position or deposited from a squat. Spraying is nit usually associated with ill health. It is a way of marking territory or of expressing aggression by cats that do not have the confidence to engage in direct conflict.
Cats that are spraying or urinating in the house are often very anxious.
DEALING WITH URINATING IN THE HOUSE
Take the cat to the vet for a check-up. Confine the cat to one easily clean room when you can not supervise it, and provide a litter tray. If the cat does not use the tray while in the room, treat as described for soiling near the litter tray.
If the cat is using the litter tray in the room, typically reintroduce it to the rest of the house, having cleaned all previously soiled areas with an enzymatic cleaner. Do not allow the cat to be anywhere unsupervised. If it attempts to dig, squat or spray, squirt it with a water pistol or alarm it with a foghorn, but do not physically or verbally abuse it.
If the cat is marking territory, it may be that the social relations between the cats in the household somehow changed. Marking is often seen when a new cat is introduced to the household, masking may be done in response to a visitor staying for a few days or a new partner moving in. It can also occur in response to the presence of cats outside the house, and as a reaction to strange cats entering the house. Try to identify any major trigger factors. For example, if the cat is urinating or spraying on the windowsill, it is probably reacting to the presence of a strange cat outside. Fitting blind to the windows and keeping the cat out or the room when these blinds are not closed will solve the problem. If you have seen strange cats hanging around, invest in a cat door that is electronically operated by a trigger on your cat's collar. This ensures that no other cat can enter.
If you feel that the cat may be stressed by changes that have occurred within the household, try to provide it with extra attention and some stability by playing a game with it at a fixed time daily. This helps to reduce anxiety.
These problems can be difficult to solve and you may need the help of an animal behaviorist to identify the cause of the problem.
PREVENTING SPRAYING IN THE HOUSE
Ensure that strange cats can not enter the promises and the there are enough clean litter trays. Try not to change the home environment suddenly. Introduce the cat to new flatmates before they move in and take things slowly, Take care to introduce new cats or other new pets to new ct gradually too. Provide some routines and ensure that each cat has a special place to which it can retreat, such as the shelf on a cat tree, cupboard od cardboard box where it will feel safe.