Place bacon in a large pot and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Drain bacon slices on paper towels; crumble into pieces when cool.
Reduce heat to medium-low and add bacon grease to the pot. Add celery and onion; cook and stir until starting to brown. Slowly pour in water; bring to a boil. Reduce heat, cover, and cook until vegetables are soft, about 1 hour.
Return bacon pieces to the pot. Sprinkle in thyme, sage, onion powder, parsley, and white pepper; stir to combine. Add cubed ham; simmer soup for flavors to combine, about 30 minutes.
Stir peas into the soup; cook until very tender and they start to disintegrate into the soup, about 30 minutes.