Here are some things to consider. I can tell you from personal experience that the problem can be fixed. The important thing is discovering the cause of the problem.
Cats who are suffering with bladder or kidney infections will often avoid the litter box because they begin to associate it with pain. This is one time when you will need to see your veterinarian to make a correct diagnosis in order to fix the problem.
Location of Litter Box
Placing the litter box in a place where kitty can’t easily reach it or in place that is so crowded that the cat feels vulernable, will discourage use of the box. If there are multiple cats, you need to determine whether the alpha cat is preventing the others from using the litter box.
Not Enough Litter Boxes
Speaking of multiple cats, you may need to add extra cat litter boxes to accommodate all the cats. Some cats do not like to share their litter box and that may cause them to seek other places to relieve themselves.
The Kind of Litter
Cats are known to be pretty finicky and not too interested in which cat litter is currently on sale. Changing the brand of litter can cause some cats to turn their back on their litter box. It can be the texture or the smell that causes cats to reject the litter. If you are going to change the brand of litter, do it gradually by mixing both together and then gradually reduce the mix until you are only using the new brand.
You’ve Introduced a New Cat
A new cat has either come to stay at your house or was just there for a visit. Cats can be very territorial and bring a new cat into your home and your cat or cats are going to want to mark their home. A friend of mine decided to foster a kitten for a few weeks. Suddenly her own cat, who was fastidiously clean started urinating everywhere, including my friend’s bed and favorite suede chair. This behavior continued until the kitten was gone. Cats own us and our homes and they have no problem letting that fact be known!
The Cat Litter Box is Dirty
One of the biggest reasons that cats avoid their litter boxes is because the litter is dirty. They do not like having to jump over clumps of dirty litter nor do their sensitive noses appreciate the odors. This means that the cat litter box needs to be “picked” at least daily: this means removing the obvious piles and wet litter. You can never scoop too often. The entire cat litter box needs to be completely cleaned at least once every two weeks or as needed.
You and your cat can solve the problem of not using the cat litter box with a little investigation and some simple changes.