Preheat the oven to 350 degrees F (175 degrees C). Grease a 2 1/2-quart baking dish.

Place bacon in a large skillet and cook over medium-high heat until crisp, about 10 minutes; drain and cool on paper towels. Crumble bacon once cooled.

Mix bacon, beans, onions, water, brown sugar, ketchup, molasses, vinegar, mustard, salt, and garlic powder together in the prepared baking dish. Cover the dish with aluminum foil.

Bake in preheated oven until bubbling, 45 minutes.