Was litter trained, now going on carpet again

My 4-5 week old boy has been litter trained for a week.
He was absolutely perfect in using the litter box for a whole week, without fail.

Just today he has decided he doesn't like the litter box anymore.
He now urinates on my carpet unless I physically put him into the litter box myself, in which case he will then use it.
I've caught him doing this 4 times today, and that's just the times I saw.

Most of the time he is doing it on the same patch of carpet.

I have read this thread
http://www.thecatsite.com/forums/showthread.php?t=9563
and plan to try some of the remedies here.

But I'm really wondering WHY this has happened today, when he has been so perfect for the past week?

its possible he may have smelled a particular odor on that patch of carpet and decided he needed to "mark" or pee on that area. Since he did it once that had become an area for him to pee. I am not really sure why cats or animals for that matter will do peculiar things. My cat of 2 years has been liter trained of course but she went three days of peeing on by comforter, pillow and towels in the bathroom. Nothing in her environment changed nor did she experience any sort of truama. Nothing I know of could have set her off. The vet checked her out and said she was healthy. They gave me a list of things to do to see if it would help, sort of like what is on the thread you attached to your post. We free feed and one of the things on the list said to feed on a schedule. We did that and made sure to clean her litter box every other time she went to the bathroom. She quit using the bathroom on our beddings and went back to her liter box. We since then we have gone back to free feeding and cleaning her litter box every few days (like we use to). Needless to say it was a strange thing our cat did. I don't know if she was trying to tell us something or if she was just being bad. But we are back on track and I guess over all that is the important thing. I hope you find a remedy for your guy.

There's something called Zero Odor. maybe in pet stores, or cleaning supplies in the supermkt, and it's one of the very few (2+) cleaners that really does remove the smell (as far as the cat is concerned). After you use it (or one of the other ones) then for a few days or so put something on top of the spot so he forgets about it.

Is the box clean enough? Is it the same litter you've been using? You may need to get two boxes because sometimes they don't like to do both in the same box (picky kitties!)

Is he 4-5 weeks or 4-5 months?
If it's weeks, then he's probably just not fully litter trained yet. He's still a baby and won't always be able to make it to the box in time.
If it's months, then make sure you get the smell of his previous stains out completely, and you may even want to get him check out by a vet to make sure that he doesn't have a UTI.
The fact that he keeps going in the same spot makes me think he can still smell his pee there. I like to use Nature's Miracle to clean up pet stains, don't know if it's available in Australia though.

~Julia

He is 4-5 weeks. He seemed to be perfectly trained, he would always use the litter up until yesterday.
I will look for those cleaners that you guys mentioned though I doubt they are available here.

I clean the box twice a day usually. If he does a poop I change it completely, so it's not a cleansing issue I dont think.
I figure he is just being rebellious or explorative.

Im going to try the citrus trick if I can find a product with that scent, see if that does the trick.

Cats don't do this type of thing to be rebelious. There is always a reason. I think the most likely reason is that he is so so young. Usually they shouldn't be away from the mother cat yet, she is the one to teach the babies how to do that. Confine him to a small room (such a young kitten should probably not have free run of the house anyways) with maybe 2 litterboxes. Some cats like to urinate in one and poo in the other.

He is in my bedroom 95% of the time. He only goes out under supervision.
I just put another litter in his favourite peeing on the floor spot, but he still went to do it on the floor - i had to place him in the litter.

I hope you're right, and that he's just doing it because he's young!