It may be a 'disturbance' in her life. It may be a valve / UTI issue. It might be worth seeing a developmental pead. (They all seem to have differnet theories though - attention seeking, distracted, lazy, trauma, autism etc). Any change / reversion in development should be monitored. I understand though. I have a 4y8m who has done the same. I am pretty sure it is school related. I spend some time in the class observing interactions now. He seems reassured when I am there. Slow improvment but some days are better.
Interesting. She WAS completely potty trained but now she's reverted to peeing her pants again ...
Has there been a new babysitter? Is she being bullied at daycare/preschool?
Or is there a baby or toddler that she's been exposed to lately?
These things could cause her to start it up again.
Buy Febreeze - and add baking soda to her laundry in the wash. There'll be no more urine smell. Unless of course it is in her mattress - then no help there except a new one then cover it with waterproof mattress cover. Pillow too.