My Lab has jsu started weeing in the house

[topsi]

My choc lab who is an un neutered male 2 yrs old has started weeing in the house.
3 times now we have come down in the morning and found he has weed in his bed. We have just come in now after being out for 4 hours and let him out of the kitchen to go out the back door and he weed on the floor.
We have not had this problem before even though he is left for periods in the kitchen sometimes.
My DH sais that he pees constantly when out for walks but I thoight that this was just marking teratory.
He does drink quite a bit but have not notice this increasing recently.
Is this a matter for the vet or a behavioral issue.
He gets let out in the garden frequently during the day doesn't whine at night to be let out.
Any advice would be welcome please.

[topsi]

thank you thunder. I have not actually seen him doing it but aparently he looks unaware that he is doing it looks like it is just leaking out.
Will let DH attempt the sample!!