In a large pot, cook beef over medium heat until brown, 8-12 minutes; crumble beef. Drain grease and set aside.
In the same pot, heat oil; saute onions until tender. Add garlic; cook 1 minute longer. Stir in the green pepper, salt, chili powder and cumin. Cook for 5 minutes, stirring until combined.
Add canned beans, tomatoes and ground beef. Stir in water. Bring to a boil. Reduce heat; cover and simmer for about 2 hours.