Some things that could cause them to spray or mark are you bringing home something new such as another cat, dog, baby, or furniture. If it's another pet then introduce them slowly. Let them get used to each other. Remember to let them know that you still love them. They will need lots of your attention to accept this change. If you bring home a new family member, have your cat acclimated to the smells and sounds that accompany them. Still make sure that you give him/her lots of attention. Cats need to be assured of their place in your home and heart. If there are cats outside, they may be in your yard, marking it, claiming it. Well, your cat will claim it too, he/she will let them know this is not their yard, by peeing on windows, glass doors, and anywhere he/she think they will notice. You can help your cat feel secure by getting rid of the cats out there. Find out who they belong to and tell their owners so they can keep them closer to their home. If they are strays, you can call a local humane society. If you cannot keep the cats away, then block my vision of them. You can put newspaper, foil or reflective tape over the window so I cannot see them. Cats will not spray unless they have to.
Cats spray (urinate) in order to mark their territory
There are plenty of differences between the anatomy of male and female cats, but the ability to leave scent markings is not one of them. Both kitty girls and guys have glands in their cheeks, paws and near their bladder that produce a liquid containing pungent chemicals. You may not notice an odor when your kitty rubs her cheek on your hand, but you'll definitely notice one if she starts spraying. Urine marking has an acrid and offensive smell. If your cat's rogue urinating doesn't smell particularly bad, she may not be marking at all. Cats avoid litter boxes that are dirty or if they don't like the litter.
Stop your cat's spraying!!! This really works!! - YouTube
Statistically speaking, your innocent Miss Kitty is much less likely to spray than a boy. About 1 in 20 fixed females leave urine markings, which is only about half the number of neutered males who do it, Cornell University College of Veterinary Medicine reports. Having your cat fixed by the time she is 5 to 6 months old can prevent spraying altogether. Intact cats are more than two times as likely to spray compared to fixed felines. After your cat reaches puberty and her hormones kick in, it may be hard to stop her from spraying even after she's fixed. If your cat does leave a urine marking somewhere, clean it up as soon as possible so she doesn't make it a habit. This is particularly important if you have more than one cat, because one spraying could prompt the others to do it too.
Urine spraying or marking by cats is a normal behavior