Combine peas and water in a medium Dutch oven. Cover and let soak overnight.
Place Dutch oven over medium heat; add onion, celery, ham, salt, and pepper. Bring to a boil. Reduce heat; cover and simmer 3 hours, stirring occasionally.
Add milk; heat just to boiling, stirring occasionally.
Ladle soup into individual serving bowls; serve warm.
Oxmoor House Homestyle Recipes
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