Remove cat urine scent before introducing a new cat

Introducing a second cat is a smart time to do a thorough scent reset — your resident cat's urine marks act as territorial signals, and if the new cat picks them up, it can trigger stress and conflict from day one. The only products that permanently eliminate those odours are enzyme-based cleaners. Anything else just masks the smell temporarily, which means cats keep returning to the same spots and the tension doesn't go away. To point you to the right product, can you tell me which surfaces are affected — carpet, hard floor, sofa? And are these old set-in marks or more recent ones?

Got it — set-in urine in carpet is the trickiest situation because the urine has soaked through the fibres into the underlay, and that's where most of the odour is actually coming from. A surface spray won't reach it. You need something with a high enzyme concentration that you apply generously and leave to penetrate properly. Before I confirm the product, is this spraying behaviour or actual urination? And is it one specific cat or do you have more than one currently?

That makes complete sense — a neutered male can still spray heavily when stressed, and a house move is a big trigger. The good news is the behaviour will likely settle once he feels secure, and removing the scent markers properly actually helps with that too, because he stops re-marking the same spots. For set-in cat urine in carpet, including spray marks on skirting and walls, I'd go with Simple Solution Extreme Cat Stain and Odour Remover. It has a stronger enzyme formula than their standard version, specifically formulated for cat urine which is more concentrated than dog urine. The key with carpet is to soak the area — don't just mist it. You want the solution to reach the underlay where the urine has pooled. Leave it for at least ten minutes before blotting.

For hard surfaces and painted walls, the same product works well — spray it on, leave it for five to ten minutes, then wipe. The enzymes break down the uric acid crystals that carry the smell. One practical tip: use a UV black light torch in a darkened room before you start. Cat urine fluoresces under UV, so you'll find marks you didn't know were there. There are almost always a few hidden ones, especially along skirting boards. Treating every mark is important — if you miss even one, the new cat will still detect it.

Once the scent is cleared, the introduction itself matters as much as the cleaning. Keep the new cat in a separate room for at least a week so they can smell each other under the door without direct contact. Swap bedding between them so the scents become familiar. Feliway MultiCat diffuser is worth having running in the shared living space — it's a synthetic pheromone that reduces tension between cats in the same home, and it's well evidenced. The combination of a proper enzyme clean and a gradual scent introduction gives you the best chance of them settling together without conflict.