Almost 4 Y/o Having Numerous "Accidents"

My step-daughter did that at about the same age. She would wet herself at school, sometimes even twice a day, because she just didn't feel like taking the time out from whatever fun thing she was doing to go to the bathroom. Eventually my husband lied and told her we weren't going to bring any more clean clothes to school for her to change into (we still did, but told her teachers not to tell her either). She miraculously regained control of her bladder and didn't have any more accidents.
Since your son is at home you can't exactly tell him that there isn't anything to change into but you can go out of your way to make it a real pain in the butt for him. I wouldn't go so far as to punish him at this point but certainly make him clean himself up, clean the floor/chair, put his dirty clothes in the washer, etc. Hopefully he'll realize it's less trouble just to use the potty.

what changed in your household? Children just don't un potty train. they have accidents but not daily. Talk to your peditrician it could be psycological

if he has been accident free for so long it might be that he is being lazy and u may want to try some sort of disipline for a while every time he does it without saying anything, if u think he is just being lazy, but if he keeps doing it u might want to take him to the doctor and have him check just to make sure that nothing else is causing him to wet his pants when he knows to use the bathroom.

OK, I feel for you - you definitely have a challenge. I don't know if you are into Natural help, I am all about it - I am anti-drug if at all possible, especially for kids (which nothing is approved for - no one wants their kid to be the ginnipig). Look at this website www.nativeremedies.com under Children under Other Childhood Issues, they have several that may be of help to you (BeDry). My son is on 2 products of theirs and having awesome results plus the lady that created the company use to be a pharmasist, so she understands drugs. The explain everything about the supplements and why they work. Hope this helps and let me know if I can help anymore. Best of luck in your Journey to Complete Health, K.