You need to pull up the carpet and the padding, check the floor under the padding and treat that with the peroxide followed by nature's miracle. This may take more than one application to get all the smell out. Will have to throw out the padding and get new. Sometimes flooring stores will give you or sell you remnants from installs that you can patch in.

Are you sure that the cat is not repeatedly soiling the spot?
Also sure that you are finding all the spots?

I'm renting so ripping it up is not an option. She went on antibiotics so I don't think she's still doing it. I think it's because it's damp from all the times I try to clean it.

I use a black light to find the dreaded spots so I know where they are..

The man who cleaned the carpet in a rental said you can't get rid of cat urine smell, dog yes, not cat.

Cat smells are IMPOSSIBLE! I would try an enzymatic cleaner of some kind, like D-Molish Now. They are non poisonous, so will not hurt your pets or children OR future pets or children that may inhabit the rental. Anyway, cleaners with enzymes tend to help because the enzymes "eat" the odor-causing bacteria, rather than covering it up. Good luck with this! It would be horrible if you had to pay for a carpet that was already old and yucky.

I second the enzyme cleaners. Years ago my set of cats at the time peed on two layers of pillows and the underlying mattress/boxspring during our 2 week vacation. The product I used was OUT! concentrate (ready to use spray didn't work as well..maybe they have improved it in the last 20 years). Mix with warm water (not hot) to activiate the enzymes then keep damp for 24 hours (used a damp towel). After a couple of treatments, no smell remained even in the mattress. When the concentrate was getting hard to find I started stocking up on it..not sure if it is still available.

I have an older cat that was urinating daily on my nice furniture. The smell was awful. I would put a ton of baking soda on the spot. Then place a towel over it and press down. After I got it all the wet up on the towel, I would let the baking soda dry, maybe a day or two. I would then vacuum it up and then spray/saturate with Nature's Miracle spray in the red bottle. It worked wonders. I have bought it from both Amazon and PetSmart.

P.S. I solved the problem by putting the cat box right next to where she sleeps. Awful to have it in the dining room, but....

Karin

Here is a link that might be useful: Amazon link

Zero odor spray r from bed bath and beyond does amazing job at clearing up odors ! Give it a shot . If not , the store stands behind the product and will refund you.

This really works on odors - put a bowl of vinegar in the room near where the cat peed. You will be amazed at how it takes care of the odor. Not sure if it would be a permanent fix.....but it will help. Also works if someone smokes in the house. We don't smoke but if guests are coming, I am not going to tell them not to smoke - just put the vinegar bowls out and the smell will disappear. You might smell a bit of the vinegar for awhile but beats cat pee and smoke any day! Also good to put in cars overnight to get rid of odors. A cheap and easy fix!
Judith