This is a specific conversation about Pet stain and odour removal — what actually works — ask about yours and get one honest answer for your exact situation.
inparticular.ai
Top-floor flat with a Shih Tzu and no overnight garden access — repeated spots are almost inevitable in that situation, so you're dealing with a very common problem. The key thing to know upfront: the only products that permanently eliminate pet odours are enzyme-based cleaners. Anything else — sprays, carpet fresheners, even steam cleaning — masks the smell to you but not to your dog, which is exactly why they keep returning to the same patch. Before I point you to the right product, can you tell me which surfaces are getting hit most (carpet, hard floor, sofa?), and are these mostly fresh accidents or have some been soaking in for a while?
It's mainly the carpet in the hallway, a couple of spots in the living room too. Mix of both — some are fresh, but there's one patch in the hall I think has been there for ages because he keeps going back to it no matter how much I clean it.
inparticular.ai
That set-in hallway patch is the one to tackle first — that's the scent anchor pulling him back every night. Carpet is actually the trickiest surface because urine soaks through the fibres into the underlay, and standard cleaning never reaches it. A few quick questions about your Shih Tzu: is he drinking normally, and have the accidents increased recently, or has this always been his overnight pattern? Just want to rule out anything medical before we talk products.
He's always been like this overnight, the vet checked him out last year and said he's fine. He just can't hold it all night — he's five but he's always been a bit needy with toilet trips. We try to do a late walk but living on the top floor it's not always practical at midnight.
inparticular.ai
That makes complete sense — some Shih Tzus genuinely have smaller bladders and an eight-hour overnight stretch is a long time to ask. Since the behaviour is structural rather than a one-off, you need a product robust enough for repeated use on the same spots without damaging carpet fibres. My clear recommendation is Simple Solution Extreme Pet Stain and Odour Remover. It uses a pro-bacteria enzyme formula specifically designed for set-in urine, it works on carpet and underlay, and it's one of the few products that genuinely breaks down the uric acid crystals that cause the odour dogs can smell even when you can't. For that old hallway patch: saturate it, cover with a damp cloth for 10 minutes to stop it drying too fast, then blot — don't rub. You may need two treatments on a really ingrained spot. It's widely available on Amazon UK, usually around £10–£12 for a litre trigger bottle.
That sounds good. Is there anything else I can do alongside that to discourage him from going back to the same spots once they're clean?
inparticular.ai
Yes — once you've done two solid enzyme treatments and the smell is genuinely gone, you can reinforce the message with a citrus-scented deterrent spray on those spots. Dogs dislike citrus and it adds a second layer of discouragement. But honestly, get the enzyme cleaner working first — if any trace of uric acid remains, no deterrent will hold him back. You might also consider a pee pad station near the front door for nights when a late walk isn't practical. A five-year-old Shih Tzu who's used to going outside will often accept a pad as a last resort if it's consistently in the same spot, and it at least protects the carpet while you retrain the pattern.
Really helpful, thank you. I'll grab the Simple Solution and try the double treatment on that hallway spot this weekend.
inparticular.ai
Good plan. Give it time to fully dry between treatments — rushing it is the main reason people think enzyme cleaners haven't worked when actually the job wasn't finished. If that old patch still has a faint smell after two rounds, a UV blacklight torch (a few pounds on Amazon) will show you exactly where the urine has spread under the surface, which is often wider than the visible stain. That way you know you've covered the full area. Good luck with it.
