I wouldn’t worry at all. 3 is still in the realms of “perfectly normal” to need nappies at night, and this was even the case 30+ years ago.
Just in case it works, however…
Posted on an earlier thread about this topic: My story and advice in full:
Could it be black current juice or other cordials with artificial sweeteners that is causing it?
I was a Ribena junkie as a kid and my parents never made the connection between blackcurrent juice/ cordials and my late bed wetting.
They were not cruel about it in any way and bought specialist “child size” night nappies from the Chemist for me to wear to bed so as to avoid soaked sheets (there were no Pull-Ups or DryNites then).
We had occasional periods of “trying without” but I always wet my bed when this happened. I wore nappies to bed far older than your child is now.
Fast forward to being Mum, and both DD’s had the same issue as me and I just assumed that they had inherited my bladder issues.
I didn’t want to stress either of them out and they both wore DryNites without getting embarrassed or upset (the fact that they go up to age 15 and say so on the pack helped, I think!)
Then a friend told me about blackcurrent juice and how it irritates the bladder causing it to empty by reflex and how other cordials and “juice drinks” with artificial sweeteners have the same effect.
We experimented, initially for just a week, with just water and milk.
It was like a miracle cure. Almost overnight the bed wetting stopped and after a few nights of dry DryNites we donated the remaining supplies to the food bank.
We added fresh fruit juices back into the mix as an experiment a few weeks later and that didn’t cause any problems but neither have cordials any more, and neither has wet the bed since.
My eldest was eleven at the time and had never been dry.
We had already done the whole experimenting without the DryNites for a few nights, cutting out fluids after 6pm, even the alarm thing (which we ditched after less than a week because it woke us all up) and GP hadn’t identified any issues. Both are NT, no disabilities or anything like that.
So if he has cordials (blackcurrent juiced and Fruit Shoots are the worst) try going to just water and milk for a week and see if it becomes your miracle cure too.
I wish my parents had known this as they would have saved hundreds of pounds on night nappies if they had stopped me having Ribena and had I tried this earlier I might have also saved hundreds on Pull-Ups and later DryNites!
I’ve posted this on other posts here because I’m a bit of an evangelist- it was like a miracle cure for mine and I hope it is for yours too.
Good luck