I have a three y/o cat and a nine y/o dog. The cat knows to use the litter box when left in the restroom...?

But when I let her out she'll wait until I'm not paying attention and pee on the couch. She is a spayed calico cat. We have two couches all have been peed on multiple time. How do I teach her to only pee in her litter box? I would like to keep her out all day.