This is normal for lots of kids, and kids do tend to do what they are allowed to do if they REALLY want to do it, and if the consequence isn't enough to deter it and doesn't always happen, or they dont' really mind it enough to stop the behavior. If you let this slide for a while or were inconsistent and allowed it to escalate, be encouraged, because he most likely doesn't have a disorder, he's just gotten super used to doing it, loves to do it, and the penalty isn't unbearable to him.
It is very improtant that when you teach him that something is extremely wrong and not allowed (peeing all over room would qualify) that he respects that and does what you say.
I've heard some theories connected to poop and pee being signs of other trauma at times and like anything else needs addressing do he doesn't feel neglected. He could be having some sort of stress, or he could be feeling a lack of boundaries so he's massively pushing them-assess his total picture when choosing what to do here.
You say he's been doing this for almost 3 years, and you have tried taking things away and making him clean it, and you're not saying he has any other issues making him seem like something is neurologically wrong. Are these consequences you're using things that have worked extremely well for all his other behavior lessons? Has he stopped everything on a dime when you did these after just a couple of times? Did you do these things EVERY TIME the very first few times he ever did it and never let it slide even once, but he's still doing it 3 years later?
If you feel cleaning and toy removal are effective consequences, you should somehow increase the seriousness of them by applying them right away every time, and if you have, and they're not working, then they're not effective. Also, cleaning is not a negative consequence, it's a responsibility, and should be used after a consequence, not used as a consequence. Be sure there is no negativity associated with cleanign up his mess. That's something we all have to do after spilling something or whatever, it doesn't teach a lesson.
You should think of a way to make his life better in a few ways and the consequences firmer to show a new leaf has turned. Have a sit down with him and tell him all good things about himself and how much you love him and all that, and since he's getting so big and you're so proud, here are (X) new activities, privileges you will be doing together. ALSO, since he is so big etc, you will no longer allow him to pee in his room without (X) happening. Explain it all thoroughly in advance so he has been warned.
Do some fun new things with him, spend some extra time with him, improve anything you can think of in his day to day-maybe he needs some new responsibilities to make him feel important and mature.
At the same time, find something MUCH FIRMER to do when he does this, and be absolutely consistent. You know your son and what would deter him. Do not get angry or hold a grudge-keep it simple, quick and calm as in "Hey, I said this would happen if you chose to do this, and you did choose to do it, so here it is". He is absolutely old enough to understand. Once the moment is passed, go back to the happy norm-you're just doing your job-no guilt trps, no anger, no skin off your nose. He will soon learn that his life is much nicer when he chooses not to create his consequence, and he will stop. The security this gives him will also help him want to quit-kids don't like doing the wrong thing even thought they naturally try it.
Of course be sure to praise him tons when a span of time has gone by that you're sure he hasn't peed (I'm sure you do)-but you need both ends of the spectrum. The good for good, and the bad for wrong to make it click. Do this consistently for a few weeks before you consider a disorder.
Good luck!
