Machine Shed Restaurant Baked Potato Soup

2 1/2 pounds baby red potatoes, quartered
1/2 cup uncooked bacon, finely diced
1 jumbo onion, diced
1/4 bunch celery, diced
2 quarts milk
1 quart water
4 tablespoons chicken base
1 teaspoon salt
1 teaspoon black pepper
3/4 cup (1 1/2 sticks) margarine or butter
3/4 cup flour
1/4 bunch freshly chopped parsley
1 cup whipping cream
Shredded Colby cheese, fried bacon bits and/or
    chopped green onions for garnish

In large pot, boil potatoes in water 10 minutes. Drain and set aside. In large heavy pot, saut