You might try putting a potty in his bedroom and telling him that though you prefer that he use the toilet, he may use this if he wants to. He should also be required to empty it into the big potty. It seems like it might be some sort of childhood passing fear that, if treated calmly without punishment or shaming him, will just resolve itself in pretty short order. When there aren't any other major underlying medical or psychological disorders, sometimes a practical approach works wonders.
(I'm sure you've already done this, but also of course do make sure that he doesn't have a urinary tract infection.)
He hasn't yet learned to wake when he needs to go, so he does wake with a lightly wet diaper in the morning. That is getting better. The behavior occurs strictly during the day when we are close by. For example, he has an hour of quiet time every afternoon, which he sometimes spends reading and other times takes a nap. He'll urinate on his carpet during quiet time, even though the bathroom is next-door and he's previously always gone to the bathroom. Yesterday we asked him to put on his pajamas as bedtime approached, and he urinated on the carpet in the three minutes it took him to change. We were caught off guard, because we'd had so many discussions over the last two days, and he said he'd never do it again. But we found he'd done it inside his room and just outside his room while we were standing within ten feet of him.
We've taken away favorite toys one by one. We've also suspended the 30 minute daily allotment of educational television he'd been afforded. Slowly but surely, his priveleges and toys are all being taken away. It doesn't seem to faze him a bit. Yet we have maintained a loving, respectful atmosphere, but we've also been holding the reins increasingly tighter to keep our eye on him.
As additional background information, there have been no notable changes in his life or routine that might trigger such behavior. We have begun discussing that he will begin preschool this Fall, but he has been involved in the process of picking schools and has been very excited about it.
Having always considered ourselves to be thoughtful, competent parents with a loving, respectful child, we are completely stumped. We can't even seem to decide how to properly classify the behavior (e.g., manipulation, lying, limits, potty training, self esteem).
Any other thoughts would be greatly appreciated.
Is he dry when he gets up in the morning? Do you suppose this is occurring during the night? If so, it is likely associated with fear/reticence to be up alone outside his room during the night. If the behavior is occurring during the night, tell him to come and get one of you to accompany him to the bathroom. If the behavior is not occurring during the night, the reason for it may not be so obvious. Regardless, set a firm limit on it, including some standard consequence if the behavior continues (something as simple as a period of time out or loss of a privilege - e.g., television or some favored toy - would be fine). Generally, this sort of behavior occurs either during the night or very early in the morning, when people in the family are not up and about. What do you think?