4 yr old potty training issues

My 4 year old has been potty trained for almost a year. She has never had an accident at preschool or at any grandparents homes while they are sitting for us. In the past two months she has been having accidents almost daily. There have been many days that she has had more than three accidents in one day.
I have tried everything. All of the advice on the internet it really for non-pooping or how to potty train. I really do not believe this to be a potty training issue since she went nearly 8 months with an accident maybe three or four times.
Myself, her father and day care spend a lot of time with her talking to her and getting her to go often. She does not drink anything two hours prior to going to sleep. She is brought to the bathroom frequently. However, she does lie about what happens. If she has went panties she will tell you she is fine over and over.
Is this a phase?
I have tried the reward system too. No tv or playing outside. No buying new toys, no going to the zoo, etc.

[Rebecca Resnik, PsyD]

Hello,
   your daughter is indeed trained if she had full control for so long. The first stop should be to your pediatrician to rule out a bladder infection or other medical issue.

    As far as the lying goes, children her age lie frequently. It is not a sign that they are bad kids, but that they are so little. I am sure she feels stress about this and wants to give you the answer to your question that will make you happy. I would not worry about the lying right now, but tell her gently that you know she is wet and that it is time to change her clothes. Then put her back in a pull-up for a while.

You mention that you have tried a reward system, which is a good thing to do. However I notice that your system also includes some pretty serious punishments for a little child. My guess would be that the punishments are making the problem worse, as they are increasing her anxiety and frustration. You will get better results by giving rewards/attention/affection for successes rather than focusing on failures. You can check out my posts on child behavior management, however I think a better bet would be to meet with the pediatrician and ask for a referral to a psychologist or counselor who can help get her back on track. It would be great to figure out more about why this behavior is occurring. Kids lose control in times of stress, and this behavior may be a signal that she needs help. It can also be an attention getting behavior or a way of resisting control. Getting a professional to sort out what is keeping it going will be the fastest way of reversing this trend.

Best Wishes
Rebecca Resnik