get rid of all carpets, curtains, and quarter round or trim around the floor. Scrub, paint, and paint some more. If I was you, I would pack up and move. Some things are impossible. The landlord should give you your money back.
My lovely & intelligent wife says to use lump charcoal, untreated, spread it around w/ windows closed. Or try 1 to 2 ratio vinegar & water plus a few drops of dish detergent & some Listerene added. But any rugs have to go. Tile? She says to use hydrogen peroxide because of the grout, but it may discolor it. She's online right now, & says the main thing is vinegar & water. I'm thinking your landlord needs to step in, this is certainly a health risk factor. See what your legal rights are as tenants. All landlords here need a C. O. or a Certificate of Occupancy before renting. This involves a State certified inspector signing off on the C O. I really feel for you as a friend of mine inherited his grandmother's house, & guess what? Same thing. Umteen cats & a real nasty mess to clean up.
you will have to remove all carpets mad maybe a foot or so of drywall from the floor. I would remove all carpets get some heavy duty cleaners and mop floors wall counter tops mop everything then if not gone you will have to start with drywall.but after carpet removal clean everything and see if that helps
There is a cleaner that a professional carpet cleaner used on my sister's carpets after her elderly cat lost control of his bladder. It did the trick. There are also paints on the market that are formulated to remove urine odor. Ask the drycleaners if they can remove the urine smell from your drapes. Doesn't sound good, does it?