I just passed on a job and told the realtor to replace the 1 1/2 year old carpet.
I cleaned it a couple months ago and used orodcide mixed with OSR on about 8 heavy spots.
I let dwell about 30 minutes and water claw extracted.
They call about a week later and said the smell was back. The stains were gone so I pulled about 1/2 of the carpet back to investigate and there were spots about every foot or so that had not shown up on the initial inspection and cleaning. The urine had soaked thru the pad and into the unsealed concrete floor. This is an empty that has been on the market for a few months.
I hated to pass on the job but it would have required me to remove the carpet and clean thru both sides, revmove and replace all of the pad, and clean and seal the concrete floor. This 400 SqFt room had a number of columns and about 90 foot of seaming that would have to be redone.
For what I would have to charge this customer, it is simply cheaper to have it all replaced.
I found them an installer who will do it for around $500, which includes everything, carpet, pad, labor, disposal.