If you want to install a bathroom in a house and the pitch of the house runs the wrong direction, you can always install a sewage ejector by the bathroom and pump the sewage uphill. A sewage ejector is a small 18-gallon basin that sits below the ground. It has a pump grinder with a float, when the water rises up to the maximum level, the pump turns on and removes the contents by vacuum and forces the products up to the level of the sewer line. The distance the water will travel determines the horsepower of the pump.
But you may be able to drain by gravity, if the sewer line uphill is low enough below the surface of the ground. Everything will need to be determined by an estimator. You will need someone with experience to come out and discuss your plumbing installation questions with you – and review the solutions available.