We have three cats and one suddenly goes potty on the carpet, but not urinating as of yet, a 16 year old female, and this started about 6 months ago. Normally she did this once a month, but now (as of a few weeks ago) she is at 4x a week! I just rubbed her face in it and smacked her butt which I feel guilty about now. Clearly I am getting very frustrated. We took her to the vet, she had blood work done, no age related issues were detected. We are positive it is her, and we have seen her in the act. The cat boxes (two of them) are cleaned twice daily, we use unscented cat litter, a good quality dry cat food, etc. At nights when we sleep (this is her time when she does it) I am thinking about locking her up in a room w/food ~ litter box and letting her out in the a.m. I am very concerned that the other two cats will copy her actions eventually... any suggestions are appreciated?