I have a [female] domestic short hair cat. She's going to be 16 year old in February. Yes, I know she's quite an old lady now, but health-wise she's doing really well. Vet checks are good. Lately, I noticed a small issue with her. She has been peeing outside her litter box. I clean the box regularly and make sure there's enough litter in there; I just have no idea what the problem is. She doesn't go anywhere in the house, which is good, she sticks to using the box, but it seems like she doesn't completely get in it... I bought various types of litter boxes within the past few months and cannot seem to find one that contains her. I had the regular pan/tub, the box with the high sides that curve in at the top, and now have a dome... She still manages to keep her tail-end out or over the edge... I just have no idea what to do. She always was great about going and this problem just recently developed. I'm not sure if it's a "age related" thing or if she's just being 'lazy'... She poops inside just fine, it' just seems to be a urination thing... Any suggestion on what kind of litter box to use or any ideas of what her problem may be?