I recently had to put my 15 year old cat down. Two years before I had to put her down she started doing the same thing. I think it might be for lack of better words lazyness, your cat is an old lady. And she just can’t make it to the bathroom.Also make sure that they litter box is always very clean. But there is a great product called Urine Begone that works really great to get the stain and the smell out of carpet.

i have no idea but my cat is starting to do the same thing he his also old. It might be thatwant more attention.because when cats get older you don’t have the same feeling for them or may be he litter box is messed up or he like the smell of the floor

is it near a light if so leave her a lite on she may be blind but can see lite

As animals age they loose control of bladder functions
Try moving the letter box to where she is making her
messes now. Or just keep two litter boxes available
one in her regular spot and the new spot.

Jtownman,
It’s very important to keep the litter box clean (very clean), for some cats. If I don’t keep the litter box really clean my cat go’s to the box and stands on the edge and does her business in the floor, right next to the box. Cats are very finicky when it comes to their litter box. This is probably tiggered from the fact that she is getting very old and even more finicky.
TDCWH

Is it happening near her litterbox? Is the litterbox too high for her to get into?

Also, have you checked her for kidney disease?

Sounds like she is losing her “night” vision sense of direction. She’s very old in cat years (89) and slowly dying. Maybe getting a bit alzeimerish. Just deal with it and at night, put her box where her ‘new’ spot is and see if she uses it there.

She was already check for uti? What about kidneys and liver testing through blood work.

Put another litter box where she is going. Something easy for her to get in and out of. Maybe when she wakes up in the middle of the night it is difficult for her to get in and out of the one you have. 16 is OLD!!