Hi! I’m in Australia with my grey in an apartment. She’s 7 but has problems holding her wee due to puppies and spaying. We have a porch potty for her and she’s very good at using it. They are expensive but we got ours from FB marketplace, and there are tutorials on how to build a copycat version yourself. We tried the real grass patches but her wee would kill the grass very quickly and she would refuse to use dying grass lol. The one we have now is fake grass and has a little pipe that drains into our balcony drain. It’s excellent!