Chop onions and peppers. Set aside
Brown ground beef. Drain beef and make sure that most of the grease is out of the skillet. Return to skillet.
Add onions and garlic to the skillet and cook for 10 minutes over medium heat
Add peppers, ketchup, mustard and water and cook for another 15 minutes until most of the liquid is reduced and sauce is thick.
Preheat oven to 300 F
Split rolls in half and place on a cookie sheet and in the oven for a few minutes to toast lightly.
Serve Sloppy Joes on toasted rolls.