It is very frustrating when your cat begins to avoid using the litter box. If he has litter box aversion, the cat will start urinating in the house. As a cat owner, you need to help your cat cure his problem or it will continue. It's best to address this problem as soon as it starts. Otherwise, you will be faced with a cat who refuses to change and a expensive cleaning bill. Sometimes the issue can be fixed by simply adjusting the litter box.
It sounds so simple that most people overlook it. The litter box is a very important in his life. A tidy box is preferable to your cat and is not only hygienic but also healthier for your pet. Many times, a cat will refuse to use a dirty litter box. Think about it: you wouldn't want to use a dirty or smelly toilet. Why subject your cat to the same thing? A multiple cat home should have several litter boxes. The general rule is an extra litter box per each cat.
I had this problem with my male cat. I took him to the vet and did lots of research. I followed the directions of all the experts. Still, nothing worked. He continued to pee in the house and even ruined a futon. I was determined however. I knew I could help him and we could all live in harmony. Finally, I installed large litter boxes in the different areas he had been peeing. It worked! He was trying to tell me that he wanted his box in a different area. My point is, your cat is acting this way because he wants your attention. He wants something changed. Try a different non-scented litter or invest in some new litter boxes and put them in problem areas.
The actual litter box may be the problem. Most commercial litter boxes are far too small for your average house cat. The cat needs room to move around and do his business. The larger the litter box, the better. For more information, read why does my cat avoid the litter box.