We recently adopted a rescue pup, a little boy who's approximately 6 months old. He is housetrained to the extent he will do his business outside, if we see him go to the back door and let him out. If however, we take our eyes off him, he will go into the kitchen and mess there. This may not seem to be too much of a problem, but for the fact we can't keep an eye on him every second of the day watching for him to goto the back door. He simply doesn't indicate any other way that he needs to go. How do I teach him to bark or whimper or make some form of sound?
Ironically, he's rather vocal on everything else, just not this. I'm really stuck. Can anyone help?

Probably best to take him out as often as you can at the moment and if he goes then you know he will be okay for a while and if he doesn't then you know you'll need to keep an eye out for him needing to go.  I tend to let my dogs out regularly rather than wait for them to tell me they need out.  That way they are more used to going when I need them to - say if I was going out for a while - and they also know that I'll be letting them out soon so they learn to hold on if necessary.  If I only let them out when they asked, or if I taught them to ask, I would be up and down like a yoyo letting them out everytime they fancied a change of scenery. :)

My 6 month old rescue boy was like this when I first got him and it will improve but it does mean a lot of work. I would do as sally suggests and take him out at regular intervals. I actually put Zymi on a house lead so I knew where he was all the time. Is it only the kitchen he messes in and if so what would happen if you kept him out of the kitchen when you weren't in it. Our back door isn't in the kitchen so Zymi went to the door that was nearest to the door outside but at least I could see him and let him out. I also took him out on the lead if he went near the door and he was kept on lead until he did something then was praised and let off to play. If he didn't do anything he was just taken back inside so that he didn't start trying it on to get out to play.

It can be really tiring but it'll be worth it in the end, good luck
                                                                                   Anne

You could fix a bell to the door low enough for a dog to reach, you know, the sort they have in some corner shops. Then when you let him out (often, as the others have said) it will tinkle and he will start to associate the tinkling sound with the door being opened, then hopefully start to paw it when he wants the door opened. Also as he is actually doing his business give 'it' a name, I always say to mine "wee wees" they then start to associate the word with the action and after a while and you will then be able to instruct him to wee on demand. Keep at it and be persistant, try to watch him and catch him doing it indoors so you can correct him, then he'll know what is expected of him. He'll get it in the end. :-) Good luck!

Thanks for all the advice. I think my problem lies with training my hubby. He's leaving the door open all day when I'm out, which of course is counteracting my training efforts.

We use a bell hanging from the door handle too.  I love it because I don't have to be watching that room with the door.  Our dog is not a big barker so this works very well for us.  But, we also have a routine which we insist she go out like first thing in the morning and such. 

Sadie just bumps the bell with her nose.  I think it is cute except the times she just wants to stick her head out to smell.

I taught her by just bumping the bell each time as I opened the door.