...need advice. Please help.?

Have you changed a routine or is something causing him stress? It could be something as simple as moving his water and food bowl to a different room. If you know his behavior is not from a change in routine, then he could just be testing his boundaries similar to what teens do to their parents. Dogs go through an adolesent stage just like humans so just be consistent and if you catch him in the act tell him NO and immediately take him outside. It may seem like he's regressing but he's just testing you.Good luck!

First off has he been neutered? IF not, that could be part of the problem.. it is a male dogs natural instinct to mark their territory.. So he could be marking.

I would have to agree with the person who asked if something has changed for him? When we first got our male dog he was a little over a year old and house trained. He never went in the house, then we started put him in the basement went we went away (there was a 1/2 door on the door going downstairs and he had complete run of the basement). The first time we came home he greeted us at the front door. He had figured out how to open the 1/2 door. So we took off the door handle. Next time he pooped in the basement, even though I know he did that right before we left. The next time he pooped and peed in this water dish (I had never heard of a dog peeing in there own water dish). We tried leaving him upstairs and he does fine, never chewed up anything or did his "business" in the house. So needless to say he stays upstairs when we leave and yes, he won!!