Then I would say
it could be territorial or it could be behavioural. If it's territorial then you need to look at what you're using to clean the curtains and carpet with. If it's ammonia based then that will encourage him to piss there again. I'd go for a detergent from a vets or pet shop and really go to town on where he's pissing to leave no trace of the smell. Then scent with orange (real if you can without staining or get an orange essential oil to put (safetly) by the area he's marking as they hate the scent.

If it's behavioural then think about when he started doing it, how long he's been doing it for, any changes in the household that could have caused this change, that sort of thing. Cats are adaptable, but change does take time. If you can address these and nothing has changed enough to cause this problem then I'd consider getting a litter tray indoors and retrain him to use it, keep it exacly where he pisses at the moment, then moving it close to the door so he knows he can go outside to piss again.

Beyond that you need the guidance of a pet behaviourist or a vet to do urine testing and a general work up.

Edit: The plug in's are good, but only if they're being used in the room where aggro or urinating is taking place. They can take a while to kick in as well, so I advocate the feliway spray as a quick measure and the feliway plug in for long term stress.
( fuck shit up the best you never had, Mon 4 Aug 2008, 23:33, Reply)