My house is kind of small but it is 2 stories and has a basement, I put the litter boxes in the basement, some poop and pee is in the litter box when I clean it but on the other half of the basement there is tons of poop and pee. My older cat before I got my kitten never did this but since we got the kitten about 1 year ago they both have started doing this (I believe... I'm not sure who is doing it.) How can I stop this, it's driving me crazy!