Our 3 year old tabby cat has recently started pooping all over the house.he is eating and drinking well. We have 2 litter boxes upstairs and just put one downstairs in the basement were he sometimes goes now.the boxes are cleaned every day.he sometimes goes in the boxes and pee's in there all the time.
We got a kitten about a year ago and they took to each other very well and get along great.
He has just started doing this about 3 months ago.

Please any suggestions or advice on how to stop this or why he is doing this would be great. We love him to death but it has to stop.
Thanks

The stoddy family

Try washing the boxes out weekly with a decent detergent , and rinising them out with a vinegar water sloution. This should take care of any remaining smell, make sure you do the outside of the box as well. I would also make sure the area where the boxes sit, are cleaned really good as well. Some cats want their boxes scooped out often. I had a cat I had to scoop her box out each time she pooped or she would go in the bathtub... etc When she peed I would have stir the litter around to make sure it absorbed and there was no wetness. She started this when she was around a year old.