Saute the bacon until crisp. Remove and place on a paper towel to drain.
Drain excess bacon grease and saute' the onions and celery until the onions are translucent. Add the parsley and stir in. Cook for two minutes.
Add the bacon back to the pan. Add salt and pepper.
Turn heat to simmer
Heat water to a boil in a Dutch oven, then add the sliced potatoes. Cook until tender and add to the bacon, onion mixture
Add milk to cover the potatoes by about an inch. Increase the heat until hot, but do not boil.
Add the butter to a skillet and heat to medium. When the butter has melted, add the bread pieces and frequently stir until they are browned on two sides.
Put the hot soup into a bowl, top with croutons, and serve.