This is a family favorite.
Clean and destring the green beans and break or cut them into bite-size pieces (about 2 or 3 inches long). Wash and peel potatoes, cut them into ½-inch cubes. Peel and wash onion. Cut in half lengthwise and slice into 3 or 4 big chunks. Cut the bacon into ¼ to ½ inch pieces.
Put the onions and bacon into a stock pot or dutch oven and fry until bacon is almost crispy. Add potatoes and green beans. Add ½ cup water and cover. Let it steam until potatoes are cooked. Add more water if needed.