How to stop a Cat from spraying or Marking
Cat spray is inappropriate urination on objects or areas to mark territory. It can occur in any age, breed, or gender, and urine spraying is more common with males than in females. Spraying around doors or windows might be a marking response to the presence of a cat outside. Marking in the home may be a response to another cat, either in the home or outdoors. Also, due to competitive behaviors, the probability of urine spraying indoors is directly proportional to the number of cats in the household.
Causes of Spraying and Marking
You should also consider the possibility that there may be a physical cause for the behavior. Following are some possibilities:
  1. Liver disease
  2. Hyperthyroidism
  3. Urinary tract, kidney or bladder stones
  4. Excessive glucose in the urine (diabetes mellitus)
  5. FLUTD, including inflammation of the bladder (cystitis)
  6. Old age (neurological issues that are due to senility)
  7. Feline leukemia virus (felv) 
  8. Recent medical treatment
  9. Stress
  10. Urinary tract infection 
How to Stop a Cat from Spraying or Marking
  1. The simplest way is to neuter it. This method is effective in 90% of all male neutered cats. However, neutering should be performed before the animal reaches sexual maturity - at the age of 4-6 months.
  2. The litter box should be kept tidy and clean. The cat may start spraying if the box is dirty, scented or in a bad location. You shouldn't use scented cleaning agents to wash it.
  3. Try reducing the cat's stress by maintaining a routine. Changes can make the pet spray.
  4. Give your pet attention and affection. Play, massage, talk to him/her. Happy animals that are not threatened usually don't spray urine.
  5. Some cats spray urine near doors and windows where they see other cats. Try to reduce your cat's exposure to other cats, so it doesn't feel threatened by them.
  6. You should clean soiled areas very well as cats commonly urinate on places that smell of urine. Avoid using cleaning products that contain ammonia. And keep in mind that your cat can smell many things that you probably can't.
  7. If you have many cats in the house, spraying may become a very serious problem. Cats spray because of the competition between them. However, if spraying is caused by other reasons that cannot be determined or eliminated,drugs may have to be used to deal with the problem.
  8. Hitting or yelling at the cat will not make your pet stop spraying. On the contrary, this will only make the problem worse. You should try to find out why the cat is doing so, not to punish it for doing it.