My son is similar, except I still put him in a diaper when he sleeps (both nap and at night). I just attribute it to him not wanting to stop playing to go potty. (Do make sure it's not something mental going on in her life--is your job or your husband's job suddenly stressful which may be causing stress in the home, and therefore stress in your daughter's life? It can happen.) I know when my son needs to go potty, because whenever I give him some juice to drink, he guzzles it and then has to pee a few times after about 15-20 minutes. So after giving him his juice, I'll set my mental clock to watch him to make sure he's going, and if not, remind him before he wets his pants. If he says he doesn't have to go, and then 5 minutes later he's all wet, I do punish him for that. Usually he takes himself just fine (and has for months), so I know he has the capability....just not the desire sometimes.
One more thing--does your daughter get positive reinforcement for wetting her pants? Does she get to spend more time with you (since she's getting washed, new clothes, etc.) than she would if she behaved herself? If that may be the case, you might need to step up the amount of time you spend with her--read her extra stories, turn off the TV and play with her at night, or just involve her in the activities that occupy your nights, whether that's cleaning the house or doing laundry (she can help put clothes in the dryer, or can hand you clothes from the basket to put into the washer).