Whether your tub won't drain or hold water, the first thing you need to do is determine which kind of drain you have. There are five basic types of tub drains: foot lock, roller ball, lift and turn, pop-up and plunger. Pop-up and Plunger tub drains have trip levers, mounted to the tub wall, that seal and release their stoppers. Roller ball, foot lock and lift and turn tub drains do not have trip levers. Compare your tub drain with the illustrations to determine which type you have. A beginner level DIYer should be able to repair a tub drain in about three hours with common household tools.