Heat oil in a 6-quart crock pot, add pork, onion and garlic and cook until pork is browned. Drain excess grease.
Add the water, chilies, enchilada sauce, tomatoes, taco sauce, bay leaf, salt, pepper and oregano, and cook over low to medium heat about 2 hours, stirring occasionally. After 2 hours, add more water if needed. Adjust seasonings if desired, and simmer 2 to 3 hours longer.