Bring a large pot of lightly salted water to a boil. Add penne, and cook for 8 to 10 minutes, or until tender. Drain.
Heat a large skillet over medium-high heat. Add ground beef and onion; cook, stirring to crumble the beef, until evenly browned. Drain off excess grease, and mix in the cream of onion soup, cream of chicken soup, and Cheddar cheese soup, along with the water and sour cream. Simmer over medium heat for a few minutes. Stir in the cooked pasta, and serve immediately.