Crock pot BBQ pork

• 1-2 cups chopped celery
• 1 cup BBQ sauce
• 1 cup ketchup
• 1 medium onion, chopped
• 1 teaspoon garlic powder
• 1 teaspoon chili powder
• salt and ground black pepper to taste
• 1 (4 pound) pork shoulder roast

Combine ingredients, add pork to crock pot, and pour sauce on top. 

Can add water if needed, but final was way too watery with original 1/2 c water.