To stop your cat from spraying inside the house, you need to understand what's the root of the problem. A visit to the vet might be in order. He will be able to look at the problem closely and figure out whether Kitty needs medication to treat an underlying condition. Special cleaning products and home modifications also go a long way to stop the behavior.
Have Your Cat Spayed/Neutered
Urine-marking is common among nion-neutered males, but females may also mark their territory when they're in heat. Marking is especially common if you have several cats in a household, as males will compete for territory. The American Society for the Prevention of Cruelty to Animals points out that many cats, male and female, urinate around the house as a "reproductive advertisement," announcing they are available and ready to mate.
While spaying/neutering doesn't always fix the problem, it's a good start. The earlier the surgery is done, the more likely you'll see positive results. Once a cat has started spraying, there's a chance he might continue out of habit after the surgery.
Talk to Your Vet
Whether your cat is spayed/neutered or not, there could be an underlying condition that's causing him to spray inside the house. To stop the spraying, you might need to enlist your vet's help to diagnose and treat the problem. For example, cats who refuse to use the litter box often suffer from urinary tract infection or inflammation, and sometimes from bladder infection. One common characteristic of these infections is the urge to urinate very frequently, which means your cat might end up spraying different surfaces because he can't reach the litter box on time.
Cats with diabetes, kidney disease and old-age-related conditions -- such as dementia -- might also spray the house. Your vet can prescribe the proper treatment for these conditions or help you make changes to adjust to your pet's new condition.
Many cats spray inside the house when they're stressed, or during times of conflict -- for example, when you introduce a new pet into the house, move to a new residence, get married or have a baby. Identifying the source of stress will help you decide how to deal with it.
If the conflict is due to having multiple cats in the house, make it easier on everybody by providing multiples of everything. This means several litter boxes placed in different areas of the house, as well as different cat trees or perches so each cat can have his own space away from the others.
Seal Off Access
If your cat is urinating on a particular place, such as your bed or laundry basket, close off the door to that particular room. Then place a litter box close to the area -- in the next room or behind a piece of furniture nearby, for example. This will encourage your cat to go somewhere else to urinate, helping create new habits.
Clean Areas Well
If your cat has already urinated in a particular area, he's bound to go there again because he'll smell the urine there. Regular soap or cleaning products generally are not enough to get rid of the smell, so search for an enzymatic cleaning product sold at pet stores and some supermarkets. These contain special odor neutralizers; some can help remove stains and are safe to use in upholstery.
Once you've thoroughly cleaned the bathroom spot, you can apply a special pet repellent spray, also available at pet stores, over the same area. Check labels to make sure the brand you buy is safe to use on all surfaces, then spray freely. These sprays contain smells that are offensive to cats and will make them avoid the area.