Cook bacon in a Dutch oven or large pot until crisp. Remove with a slotted spoon to a paper towel-lined plate and set aside.
Add sausage to the pot and cook in the bacon grease until browned. Remove with a slotted spoon and set aside.
Add onion to the pot and cook until softened, 4 to 5 minutes.
Add butter and when it melts, sprinkle flour over the onions. Cook and stir for 1 minute.
Gradually whisk in chicken broth, scraping up the browned bits off the bottom of the pot.
Add water, green beans, Cajun seasoning, black pepper, and garlic powder. Bring to a boil. Reduce heat to maintain a simmer. Cover and cook for 25 minutes.
Add potatoes. Stir them in so they are submerged as much as possible. If you need to, add a little more water.Cover and cook for 15 minutes.
Uncover the Dutch oven and add sausage. Cook uncovered for 15 minutes.
Stir in bacon and serve.
