Nothing smells worse than cat spray. Together with cat pee outside the litter box, cat spraying is one of the leading causes of cats being given away, abandoned or put down. Marriages have come under enormous strain, when one spouse puts down their foot to stop the cat's spraying problem or give up the cat. Tenants have been forced by landlords to either move out or get rid of the spraying cat.
This is very sad, because cat spraying problems can be solved or greatly reduced in many cases. First, though, we need to tell the difference between cat spray and cat urine. Spray is actually a bit of urine mixed with pheromones secreted by glands in your cat. The positions your cat takes for spraying is also different from peeing - they stand straight up and lift their bottoms high up in the air to spray instead of squatting to urinate.
Both male and female cats spray. Unneutered males are the most likely to have this problem, neutered female the least likely. Although spraying is considered a problem by people, it is a perfectly natural behavior for cats.
Do be aware that your cat may suddenly start spraying when he is sick. For example, inflammations of the bladder are known to cause cats to spray. If your cat is neutered and he suddenly develops this behavior, you should take him for a check-up at the vet before doing anything else.
On major reason for cats spraying is to attract mates. Female cats in heat spray to advertise that they are ready. Male cats spray to mark their territory - they are saying "Keep out! Females here are mine!". This is one reason why you should always neuter your cats. Unneutered tomcats are very likely to spray. Once he develops this behavior, it is very difficult to stop even after you neuter him. Many vets are willing to neuter your male cat as long as he is at least 6 months old. Some prefer to wait until he is 9 months old while others are willing to do it even earlier. You should also spay female cats when they reach 6 months of age, before their first heat.
When you bring a new pet or new family member home, this can also cause your cat to spray. Whether you explain it as stress and insecurity or territoriality or dominance behavior, it does not really matter. The point is to make kitty feel safe and secure again. Once you successfully make him feel that he is still Numero Uno, he will stop spraying. While your vet can help you to investigate why your cat is spraying, you know kitty best. You are the best person to figure out why he is spraying. Asking your vet to play private investigator can take quite a long time - he will take a step-by-step methodical approach to the problem. Cases have been published in journals for veterinarians where it took years to resolve the problem. If you really love your cat, you are still the best person to make him stop spraying.
Once your cat has sprayed a particular location, he is likely to go back and spray it again. One way to stop this is to thoroughly clean the area he sprayed. Normal soap and water will not do the job. Just because you cannot smell anything does not mean your cat cannot smell anything. The best solution is to use a blacklight (UV lamp) in the dark to find the spots and clean it with an enzymatic cleaner like Nature's Miracle.
Cat spray is a very smelly problem which has caused many cats to be abandoned by their owners. However, this is a problem which can be solved. If you love your cat, you have an obligation to him and to yourself to stop him from spraying.