Dad’s short answer: A spot cleaner with a dedicated pet tool, used immediately. For pet messes the tool matters as much as the machine — the good ones trap solids in their own filter instead of pulling them through the whole hose, which is the difference between a quick job and a cleanup you'll regret.

Why the pet tool matters so much

A pet accident isn't just liquid. Anything solid that gets pulled into a standard hose coats the inside of it and ends up in the tank, and cleaning that out afterward is genuinely unpleasant.

The better pet tools solve this by catching the mess in a small filter right at the tool, before it enters the hose. On the upright I tested with one of these, the pet-mess tool trapping everything in its own little filter was one of the things I called out as a real design win. It turns a horrible job into a rinse-the-tool job.

If you have pets, treat that tool as a requirement rather than a bonus.

Why the odor comes back

Because the source went deeper than you cleaned. Urine soaks through the carpet, into the backing, and often into the pad underneath. Clean the surface and it smells fine for a week, then the humidity comes up and so does the smell.

Two things help. First, use enough solution and enough dwell time to actually reach down, then extract thoroughly — multiple dry passes. Second, use an enzyme cleaner for pet messes specifically. Enzymes break down the compounds that cause the odor rather than masking them, and a plain detergent won't do that.

Be realistic about the limit, though. If it soaked the pad, no portable machine reaches that. At that point it's a pad replacement, and I'd rather tell you that than have you buy three machines chasing a smell.

Dad’s Take: Get the pet tool, use an enzyme cleaner, and go at it immediately. If it reached the pad, no machine on earth fixes that.