we have been getting a cat strolling in our house as if it owns it ,vicious nasty thing scratches and hisses if i try to get it off furniture etc .the other morning at 6oclock i could hear meowing then realised the blinking thing was walking around the house ugh!.it's not a stray as i've seen it go through a bedroom window of a hose near ours every day .
Cats go where they please - the water treatment should give it the message eventually - that's the trouble, they are so flippin' independent that think they own the rights to go anywhere and do anything.
cats will do What The Funicular they want, your only option is to keep your doors and windows closed you could try a citrus spray around where he gets, they don't like the smell much