Speedy Beef Taco Soup

1 pound ground beef or turkey
1 onion, chopped
1 can Ro-Tel tomatoes with chiles
1 can corn, drained
1 can pinto beans
1 can water
1 envelope taco seasoning mix
1 envelope Hidden Valley Ranch Dressing

Brown the meat and drain. Mix beef with remaining ingredients; simmer for 45 minutes.

Serve topped with grated Jack cheese and sour cream. Serve with warm tortillas.