In a large skillet over medium-high heat, add the ground beef and cook, breaking it apart with a spatula, until browned and no longer pink, about 7-8 minutes.
Drain excess fat from the skillet.
Add the diced onion and minced garlic to the skillet with the beef and cook for 3-4 minutes until the onion is softened.
Stir in the diced tomatoes with their juice, tomato sauce, dried Italian seasoning, salt, black pepper, and water.
Bring the mixture to a simmer, reduce heat to medium-low, and cook uncovered for 5-7 minutes, stirring occasionally, until slightly thickened.
Remove from heat and let the mixture cool completely.
Divide the cooled ground beef mixture into freezer-safe containers or heavy-duty freezer bags, label with the date, and freeze for up to 3 months.
To reheat, thaw overnight in the refrigerator and warm on the stovetop over medium heat until heated through.