4 Year Old Keeps Having Potty Accidents.

Need more info.
Was he previously trained, and has lost control, or was he never really potty trained?
What happens when he has an accident. Is he punished or scolded (which might make him try to hide it)? How is it handled?
Is it only at school or at home too?
Does your son communicate well with his teacher, or is he shy?
Does he have any developmental delays in general that this might be related to?

I could think of completely different ways to handle this, depending on the answers to the above questions.

ETA: Thanks for the extra info C.. I have 2 thoughts. One is that having a schedule with reminders is still really important at age 4. I almost never ask my 4 year old if he needs to go (he always says no). I tell him - hey buddy, it's been a while since you went potty. Please take a little break from playing and try to go.

My other thought is to ask if he recently had a growth spurt. One of my kids lost control after major growth spurts. I don't know why, but it was clearly developmental. He was 100% day and night potty trained at 2.5 years old. But with every major growth spurt, he would have accidents for about a month. Then he'd be fine again until the next major growth spurt. This stopped happening when he was 5. I was very frustrated at the time - not with him, but because I didn't know what to do. It turned out there wasn't anything I could do (and there wasn't anything he could do about it either), and he grew out of it.

To me - an accident or two a day at age 4 in an otherwise healthy kid - doesn't sound like something to worry about.

Good luck!

Do they do regular potty breaks in preschool or do they just expect he'll go when he needs to?
It's fairly common right up to 6 or sometimes 7 years old.
Kids get busy playing and ignore the signals till it's too late and then are ashamed to say anything.
It won't hurt to see your pediatrician but I suspect the school is expecting him to self potty a lot of the time and he still needs reminders.

Very common in 4 year olds. Ask any kindergarten or first grade teacher, and they will tell you that they keep a box for every child that has an extra set of clothes for just this reason.

Kids get distracted and involved in what they are doing. They sit in circle time, go to snack time, go to recess, go to the arts & crafts area, all on a schedule. Breaking away to go off to the bathroom isn't on the list. The "bladder to brain" or "colon to brain" signals aren't all that strong either. So "listen to your body" idea is an intellectual discussion that has no bearing on whether he actually can do that when the time comes. The novelty of going on the potty that kids get at age 3 has worn off by 4. And a lot of kids just don't like to go in public! So they hold it in and then, boom, explosion when they can't hold it anymore. And no, they often don't tell anyone.

Honestly, I'd put him in pull-ups and just wait it out. I would also think about what types of foods he eats when, to kind of get on a schedule. Then you can reinforce it - "Okay Billy, you always go poop after breakfast" or "you usually have to go after you have raisins" or whatever is appropriate. That's as good as it's going to get for most kids. Just be patient. He will not be wearing diapers in 2nd grade even though I know you are totally sick of cleaning up after him.

By 4 it's likely you know his bathroom schedule. I'd ask the preschool's help in reminding him before he would usually need to go, and for now he should be directed to go, not just asked if he needs to (he'll likely say no if he's just asked).

Consistency will help him to begin to recognize his body's cues.

This is so perfectly normal. Some kids do it in Pre-K and others do it in kindergarten. Their brain gets so busy learning their window to potty time sort of gets closed a little bit. He'll be back on track pretty quickly.

In my opinion they are right there, why aren't they doing some sort of alarm or reminder to make him go to the bathroom every hour or so? They want to clean up Pooh?

They need to get their head out and work this out. They are in charge of him and I'd think they have a bathroom in the classroom, sounds like, to me, they are just to lazy or something to be on top of this. I'd be really mad at them for allowing this to happen.

Check with the pediatrician. He may have a bladder infection or constipation problems.

Four is still very young, so it's not that shocking he's still having accidents.

As far as pooping his pants, is it a big poop or just small amounts? If it's small amounts, look up a condition called encopresis. He may be holding in his poops and it's leaking out, making it seem like he's having accidents. If encopresis seems like a possibility, you'll want to get in with the pediatrician for advice.