Please help, my cat uses my house as a giant bathroom!?

trust me, your doing nothing wrong. I have cats and one had the same exact problem. we found out the problem though. he didn't like the other cats. he was trying to get attention by making chocolate squirties everywhere. as much as we loved him, we gave him away. we had too. I know u may not want to, but it was the only solution for us. and same here, no new family members, no loses, just wanting attention. some cats just like being on their own. we have found our cat a new home, by himself, and has had no incidents for the past 3 years

Any change in the past that was upsetting to the cat (the pet sitter in 2011, for instance) that caused her to pee elsewhere is now reinforced by smells of urine in all the places she has gone. Also, even though you don't see any fighting, any time two unrelated cats live together in a home and there are dogs, there is stress. One cat is always the underdog(cat) and feels insecure. That is the cat that is going to pee on things.

First, clean up a bathroom (the people sized room with the toilet and sink in it) with nonammonia based cleaner (rip out any carpet) and put a new litter box with unscented litter in it, the cat food and water, and the cat. Never take the cat out of this room till she is reliably using the box. NEVER.This box must be scooped at least once daily (twice is better) and completely scrubbed out once a week and filled with fresh litter. Then you can only take her out for short periods while you are keeping both eyes on her. She cannot be trusted out of the room without being constantly watched. Put away all your shoes, clothes, paper, school bags, suitcases etc: they should be in closets with closed doors anyway. If you keep the place picked up, there will be less temptation to use it as a catbox. Third, use a blacklight to find EVERY place she has peed and inject a solution of Urinebgone under the carpet into the pad and scrub the areas clean with non-ammonia based cleaners. You can use baking soda too, but it will stain some carpets and floors and has to be left down for a number of days, a decently thick layer, to work.

I would also take this cat to the vet for a urinalysis (she may have to stay overnight) to make sure she doesn't have crystals in her urine bothering her bladder, or a bladder infection. Bloodwork can be done to make sure her liver and kidneys okay and then the vet can prescribe medication like amitryptyline to calm her stress and soothe her bladder.

If you are going to try to keep two cats in a house, you must have a minimum of THREE cat boxes, not all in the same room, and they must be kept scooped at least once daily and scrubbed out and refilled once weekly. Plus the dogs must not be able to keep the cats away from the litter boxes nor harass the cats when they are trying to go.

She does do this on purpose. She is trying to tell you that she has a physical or mental problem and she needs help.