Place the rinsed split peas, diced ham, chopped onion, diced carrots, and diced celery into the slow cooker.
Add the minced garlic, dried thyme, and bay leaf on top of the other ingredients.
Pour the chicken broth and water over everything in the slow cooker.
Stir gently to combine the ingredients and distribute the seasonings.
Cover the slow cooker and cook on low for 7 to 8 hours until the split peas are soft and the soup has thickened.
Remove and discard the bay leaf.
Taste the soup and add salt and black pepper as needed before serving.