I have a 7 month old Wheaten dog  who still pees overnight usually at the back door. He is not crated and I also find the underside of his bed is damp most mornings though strangely not the top side. It is a soft bed with an inner cushion. He has managed a run of 4/5 days dry but then for no apparent reasons starts wetting again. We've tried giving water only before 7 pm  and we make sure he goes out about 11.30pm and we're up at 6.30am. I clean the floor with biological powder to get rid of the scent etc. We did try using a crate a week ago but he cried until I gave up at 2am as I was awake too . When we leave him during the day he is sometimes dry ,sometimes not . There doesn't seem to be any rhyme nor reason. We have a 2 year old Wheaten dog as well and he is no bother and just looks on in disgust when the constant cleaning of floors starts again.
The dogs are kept in the kitchen area when we are not around and in the evenings come into the lounge with us though we are always a bit wary of the little one wetting the floor but he usually stands at the door when he wants out.
I'm not sure where we've gone wrong. We did all the same things as the first pup. One way in which the dogs are very different is the wee one is always hungry and seems to drink quite a lot when water is available. I've had him checked out at the vets who said I should never restrict water. Any advice gratefully received.

I would agree never restrict water.  Could he have have a urine infection, has the vet tested it? Does his wee smell strongly.  Has he started lifting his leg, yet, and could he be marking rather than weeing, and are you absolutely sure it is him and not the older dog marking on his bed?

No his wee doesn't smell strongly, in fact it is sometimes quite pale in colour because he drinks so much water but the vet has checked this out . Obviously I don't see him weeing overnight but I'm as sure as I can be it's not my other dog.

The dampness on the underside of his bedding might not be wee. If the bed is on a tiled floor rather than a carpeted one it may be condensation caused by the warmth of the dogs bodies. Our dogs have a plastic dog bed which has a ventilated bottom and this sits on a tiled floor. In the winter I put a piece of carpet on the floor under the bed and this helps to prevent condensation forming. After finding damp bedding in the mornings but 99% convinced that the dogs were not weeing on it I suddenly realised that it was condensation :) The piece of carpet just warms the tiles up enough to stop the moisture forming.

Yes the vet tested for diabetes.
The floor isn't carpeted so I suppose it could be condensation although there is never any dampness under our other dog's bed. It's a mystery. The strangest thing is that the surface of the bed is always dry.
Thanks for replying!

Lindean,My Westie twice a week or so will go into the bathroom for a wee during the night,he has done this since i have had him, but i think well he must be watching us go in there and thinks its ok for him to wee in there as well ,just glad its a wet room we have lol lol.At least your pup is going to the door if i where you i would put some paper down till he learns to hold his water.

Two dry nights in a row! don't know why but here's hoping he goes for a hatrick!