Added comment: I did a little research and if you do want to use vinegar, use a 50/50 solution in water and use a large amount to help dilute out the urine.
Good luck!
T
Good morning to you!
Is your cat an "only" cat or are there others in the household? How many litterboxes do you have? Where are the litterboxes located in your house?
Is your litterbox covered? Does he actually get inside the litterbox and pee outside of it or is he just walking up beside the litter box? Some cats, especially bigger ones, will have their front feet in a litter box and not realize that their back end is still outside.
Is this a recent occurrence or something he has always done?
Monkeybuttorama has a good idea for moving the litterbox on top of the spot, but instead of vinegar, I would utilize something like Nature's Miracle or Equalizer. Both, in my opinion, are very effective stain and odor removers made especially for pet urine. If this has been an on-going problem, even the odor removers may not be able to get all of the urine that has saturated into the area next to the litter box. Is this area carpeted?
Let us know how things progress...
Tomcat
what I've heard works wonders is very simple. clean it up, use vinegar to destroy the smell (your cat can smell it even with household cleaners) or bleach also works. then move the litter box on TOP of where your cat was peeing
if moving it doesn't help, you can also try a citrus-based spray, as it's a cat-deterring smell, but DO NOT use the citrus if you have put the litter box on top,or if the litter box is anywhere near the spot, as it will deter your cat from approaching the litter box
I may not be much help...never really am but...
when i had my penny gwen she'd do the oposite. Well it finally stopped. What'd i'd do is if i saw her in the box i knew she was peeing when she'd walk out and turn in her circles i'd run pick her up place her in the box and waggle my finger at her. In a stern voice i'd tell her no pooing on the carpet. It worked after a couple weeks.
All i can recomend is to keep cleaing his pee from the ground, maybe he'll realize its bad. If he were a dog i'd say put his nose near it and scold him...but hes a cat and cats take things harder to heart.
Another thing
Is he fixed? Do you have any other animals in the house?
If so he may be trying to say thats his box and others have to stay away. My maine coon did that with my young boy before the younger one died...But then again maine coons and siamese are known for their territorial habits
I hope i helped a bit. :/
If you need anything else dont hesitate to message me on here.