Our situation seems similar to bboop's. We have an odor that appears to be worse in the pocket door to a toilet room off of the main bedroom. The house is about 4 years old and is on a septic system. We know of no flooding history in the bathroom. The bathroom vent pipe is close to the exhaust fan outlet on the roof. The smell in the small toilet room seems to worsen when the pocket door is closed. It also appears to worsen when the eshaust fan is on and when there a lot of water is used. The house is on a slab. However, the whirlpool tub has a small crawlspace for the whirlpool motor and pipes. The air in that crawlspace seems similar (but less) to the smell in the pocket door opening. The smell appears to be somewhat more septic-related than overtly moldy. We did find some mold in our search that we removed with bleach. Any suggestions would be appreciated. We haven't taken down the pocket door yet. We would also appreciate hearing followups from bboop and other posts above. Thanks! Sebastian and Linda

Treating pet odors is what I do for a living and I see situations like this on a daily basis. I am going to asume your basement subflooring is concrete which is porous and will absorb urine and its odors. Bleach is the strongest household disinfectant you can use to kill germs and odors and it will do good as a initial clean-up on the surface which is the key word. After the bleach has dried the concrete still has wet urine and odor below the surface that is still off-gassing. The next step is get the concrete as dry as possible by using air movers and dehumidifiers together this equipment will also dry the walls if the cats have been spraying on them. Finally we use a industrial sealer that has a moisture barrier and a odor barrier once applied we guarantee you will never smell any pet urine odor from any area we treat. Kills is designed for smoke odors, as cat and dog urine acids will eventually weaken the product and the urine odor will be back. Enzymes are temporary fixes or are for minor problems per the manufacturers instruction the area has to stay wet for up to 3 weeks for best results and @$20-40 gal do the math bleach is better and stronger. Besides you have already cleaned the area now you have to get it sealed. Oh! and toss the carpet It would cost you more for a pet odor treatment then replacement. Here is a link that might be useful: thepetodorspecialist.com

Kitchens & Baths, it just could be the paint and nothing more serious, but you never know. I would possibly invest in an inspector at this point and see what they can find out for you. If they can't find it, I would probably get out of the contract. I came across this thread and wanted to post my experience since several people had a suspicious smell possibly relating to paint. It's possibly caused by paint that had been frozen. We painted a room last winter. A few months after painting, we started to notice a funky odor, that was sort of cat urine like, yet not. We have cats, so I kept thinking a cat had to have peed in the room, but I couldn't find it anywhere. We couldn't find any other source and the walls specifically did seem have an odor, especially after the door to the room had been closed. I finally went back to the local Sherwin Williams store where I purchased the paint. The store manager came to our house and confirmed the walls had an odor, but suggested it could be mold or something else causing it. (No mold!) Even so, he gave me free of charge new wall paint, as well as their primer/sealer product to prime with. I primed and painted, and the odor is gone. We recently hired a painter to paint some other rooms and I mentioned the stinky wall paint. He knew immediately what the problem was. He said the paint had probably sat on a delivery truck in freezing weather, and the freezing causes the sulfur-like odor. He even suggested the paint store manager probably also knew what caused the odor, and that the manager should have paid for the labor to have the room repainted in addition to covering the paint cost. I feel like it's too late to go back and ask for that, but I'll keep it in mind for the future.

I'm sorry. :( I didn't mean it as bragging, just noting such a different "normal". We don't have lilacs or tulips or all kinds of other things that want cold, and it gets too hot for some of my herbs, and they croak. We have avocados and citrus but no cherries or all those lovely big apples. And we have no water. None. We used to have water, but people planted almond trees where there wasn't enough water for them, so they're irrigating them with diversion water and exporting a huge amount of our water to foreign lands in the shape of snacking nuts. Sigh.