Pour the water into a large pot over high heat and bring to a boil.
Meanwhile, in a large bowl, combine the ground beef, rice, egg, oregano, garlic salt, ground black pepper and cumin. Mix well and form into 1 inch meatballs.
Roll the meatballs in the flour, coating well, and carefully drop them in the boiling water. Reduce heat to low and simmer for 45 minutes, stirring frequently, and making sure soup does not get too thick.
Add more water, if necessary, and add the potatoes to the soup. Simmer for 1 more hour, or until potatoes are tender. Season with salt and pepper to taste.