I keep my kitten in the house, when he's not out and about the house and at nights he sleeps in our utility room, go into the room and it sinks, he is litter tray trained, I washed his bed, bleached the floors and still the room sinks, What could this smell be coming from? Its definitely coming from the cat as it only appeared when he arrived

Drains(smell comes back up thro pipe).check under sink for leaks.Washing machine not properly draining , incorrect plumbing, wash cat.

Does the cat smell if you hold them close to you.

Eau de cat?

As in if you are shutting him in the utility room the air isn't circulating so you are smelling him more strongly than if the doors were all kept open?

Failing that what are you feeding him?

What type of litter are you using?

Again both of these can give off a whiff if they are not great quality food/litter

He gets Whiskas kitten food and I am using Bob Martin cat litter,

Yes the utlilty isn't that big so it could just be Eau de cat.

How old is he ? Could he be "spraying" (which apparently can start at about 4 months of age) ?

Bob Martin stuff is rubbish (sorry but it is, there is a reason their stuff is so cheap, it's crap) get something like Catsan and see if that fixes it.

Also, the better quality food you can afford to give them (whiskas is kind of like McDonalds really, just look at the actual meat content in it) the better their wees and poos smell.

If you get him spayed as soon as you can, that will also reduce unwanted spraying which as mentioned above, can start at 4 months) the earlier you get him done as well, the less chance of bad habits developing (ie him spraying even after he's been done out of habit)

I don't mean any of the above in a having a go at you way, but as a cat owner myself it's just stuff I've learnt as I've gone on

First off don't bleach anything, use biological washing power, it breaks down the enzymes in pee, so if it is that it'll get rid of it. Bleach just makes the pee smell more attractive and encourages him to re spray (if indeed it's that)

A second call for a good litter, and when he's had his injections and been neutered he can go out which will reduce the boy cat smell.

It might be the cat litter you know, in saying that the smell linger even when I have the litter tray out but the litter tray does have the same sort of smell, Bob Martin cat litter smells like vomit anyway.

Catsan doesn't smell at all. Seriously get some and I bet you notice the difference

Some cat food absolutely reeks. I've found the 'good as it looks' range smells our house out within minutes.
And please be careful about the type of cleaning liquids you use as some contain phenols which are toxic to cats. TCP and other antiseptics are dangerous.

We had our little boy castrated at the age of 5 months, in the weeks leading up to that he was getting increasingly smelly, but has been absolutely fine since.

+1 for Catsan (esp. for long haired cats).

Catsan + better food + neutered cat = no smell.

Amen!

I'm curious. What difference does the litter make with longer haired cats?

(Always used Catsan with my mogs. They prefer the wood based one which is handy as it doesn't wreck the litter tray like the traditional gravel one.)

Since a previous cat of mine objected to wood litter so much by pooing behind my sofa, I've haven't bought it since.