comments:
My step one would be to buy a decent quality UV flashlight and see if you can figure out where the urine is. This one on Amazon is decent: https://a.co/d/0aJNJJF2 If it’s cats then the odds are that it’s in the flooring. It’s possible that it could be higher up—like at the base of the walls or something—if it was spraying. I don’t have good tips for walls. But that UV flashlight should help you figure out what’s where. If you can identify where the stains are you can treat them with an enzymatic cleaner like Nature’s miracle. Just start with that—don’t use any other cleaners first because it can mess up the enzyme action. If it’s in the floors you can soak the heck out of a spots that are stained with urine and then cover them over in some thick plastic sheeting. I used a contractor’s heavy duty trash bag when I had a cat urine stain that had soaked thoroughly into the hardwood flooring. The goal is to put down a bunch of the Nature’s Miracle and seal it in so it can’t evaporate and soaks all the way into the wood. You’ll want to leave that to soak for about a week maybe if you have the time. The floor may stain, but it’s probably already stained if it got peed on. My next step would be to rent or buy an ozone generator. Assuming that it is cat pee and you treat the actual sources of it I think that an ozone generator could work very well for this. They take odors out of things. They work much better if it’s like a surface odor, like smell from cat urine elsewhere that’s just kind of stuck onto the surfaces. I think that what the other person said about sealing stuff might be the ultimate endgame, but if you can remove some or all of whatever is causing the smell that should work a lot better. When I treated flooring the way I described it 100% eliminated the cat pee smell. Natures miracle should work on any surface, it’s just a question of how well that surface handles moisture. I don’t know how well the walls would handle it. The NM does leave its own fake perfumy scent behind, but that disappears after a week or two. It probably gets gone even faster if you follow it up with an ozone generator.
If you buy one that’s powerful enough it will show you all kinds of things you maybe didn’t want to see. There are a lot of weak ones out there that just aren’t bright enough to show you anything. https://a.co/d/0aJNJJF2 That one is pretty decent. I’m sure there are better ones out there though.