wetting his pants

my son is 6 years old and has been potty trained since 3years old with success now he is 6 and wets his pants whenever he is playing at home or outside with friends sometimes even when he is watching tv  I  have tryed to send him to the bathroom before he begins activites and that helps for some time but if we are at a party he will never stop what he is doing to go to the bathroom on his own what should i do ?

[margypops]

Is he drinking more than usual ..any tummy pains could indicate a bladder infection, .Anything new happened in his life ..new baby ..new school, does he get on well at school.