Short definition
A drain-waste-overflow kit (DWO) is a packaged tub-drain assembly with all the components needed to plumb a tub: drain shoe, drain spud, vertical overflow tube, overflow plate (sometimes with trip lever), drain tee, tailpiece, slip nuts, washers, and the stopper or linkage. Plastic kits run $25 to $60; brass kits $80 to $200.
What it is
The kit’s job is to handle two flows: the main drain from the bottom of the tub, and the overflow protection that catches water when the tub fills past the rim level. They join at a tee under the tub:
- Drain shoe — elbow under the tub bottom; bolts to the spud.
- Drain spud — threaded fitting at the tub drain hole; visible inside the tub.
- Overflow tube — vertical tube from the tub-rim overflow opening down to the tee.
- Overflow plate — decorative cover, often with the trip lever.
- Drain tee — joins the shoe, the overflow tube, and the tailpiece into a single outlet.
- Tailpiece — the short pipe from the tee down to the trap arm.
- Slip nuts and washers — seal each connection.
- Stopper / linkage — varies by stopper style: trip-lever, lift-and-turn, push-pull, or toe-touch.
UPC requires a 1-1/2-inch minimum residential tub drain. Most kits ship in 1-1/2-inch PVC, ABS, or chrome-plated brass.
Why it matters to a homeowner
A DWO kit is the typical answer for two scenarios:
- New tub install. Set the tub, run the kit underneath, plumb to the trap and waste line, set the overflow plate at the front. Standard part of a tub-set labor pass.
- Tub stopper won’t hold water. Often the trip-lever linkage is just out of adjustment — bend the lift rod or shorten it from the overflow plate side. If the linkage is corroded or cracked, replacing the entire DWO kit is a 1 to 2-hour job.
Cost-wise, plastic kits are fine for most residential service. Brass kits cost three to four times as much and shine in two cases: a luxury install where the chrome-plated brass overflow plate is part of the trim package, and an uninsulated crawlspace where the freeze-resistance of brass over PVC matters. PVC has gotten better — modern kits with chrome-plated overflow plates over PVC bodies are hard to distinguish visually.
Common failure modes
- Plastic kit gasket cracks or O-ring fails. Leak under the tub. Fix: replace gasket or full kit.
- Trip-lever mechanism corrodes or sticks. Stopper sluggish or fails to seat. Adjust linkage; replace if corroded.
- Improper assembly. Forgot the bevel washer above the gasket — leak.
- Cheap chrome (zinc-pot-metal) overflow plate corrodes. Cosmetic; replace plate only.
Common variants
- Trip-lever DWO. Classic style; most common. Lever on overflow plate.
- Lift-and-turn DWO. Stopper is rotated by hand to open or close.
- Toe-touch DWO. Stopper raised by foot pressure.
- Pop-up DWO. Pop-up stopper similar to a lavatory drain.
- Cable-drive DWO. Modern Eurostyle external cable; separate product family.