My 2 and 1/2 year old Maltese poodle has been drinking a lot of water and urinating a lot.?

I had a maltese purebred and was unable to train her, ever. I have trained many a dog before. Found out this is common with tiny breeds and that she came from a puppy mill. I would take her out, and she would go, but save a quarter size puddle just for inside. You didn't say if he is fixed or not. If he isn't, then male dogs scent. If he is fixed and this is new, he could be diabetic.