How do I remove a bathtub drain?

You need a way to grip the flange, a screwdriver, and a clear idea of what sits under the tub. There are three common ways to grip a flange, and its design decides which one fits:

• Pliers on the lugs. Kohler's retrofit guide says to insert pliers into the flange and twist it counterclockwise using the lugs. Lugs are the small tabs inside the ring.
• A drain wrench on the crossbars. Many flanges have two bars across the opening, and a tub drain wrench fits into them.
• A dumbbell-style drain wrench. Superior Tool describes its dual-ended tub drain wrench as able to remove tub drains without crossbars, without scratching fine finishes. You can turn it with a ratchet, an adjustable wrench or a heavy-duty screwdriver.

Know the parts before you start. Oatey describes a bath waste and overflow system as two pieces that share one connection to the household drain: an overflow near the top of the tub and a waste at the bottom. You are working on the waste. The overflow plate on the tub wall is a separate piece, so leave it alone unless your drain assembly is being replaced. Buy the replacement flange before you pull the old one, and take the old one with you so the thread size and style match, since tubs and manufacturers differ.

Lay a towel or a piece of cardboard in the tub so a dropped tool does not chip the finish. Then find out what the tub is made of. Kohler's guide says to confirm an acrylic bath has a floor at least 3/16 inch thick before you go on. A thin acrylic floor is one more reason to go easy.

Remove the stopper first, then turn the flange counterclockwise. Kohler says to lift the stopper and toggle out, and if the stopper catches as it comes up, to wiggle it as you lift. On many tubs the stopper assembly threads into the flange. Kohler's guide says you take it off the flange by turning it counterclockwise, so unscrew it the same way if it will not lift out.

With the stopper out, look into the opening. If you see lugs or crossbars, seat your tool firmly so it grips evenly, and turn with steady pressure. If the tool is slipping or the bars are flexing, stop. Cracked crossbars are the usual way this job goes sideways, and a no-crossbar wrench then becomes the better choice.

Work in good light and keep a rag handy for the gunk that sits under the flange. Once the flange breaks loose, it usually spins out easily. Set it aside with the stopper. In a retrofit, Kohler says to discard the old flange, so plan on buying a new one rather than reusing a worn part.

That's the removal. The rest is cleanup and putting the new one in.

The flange can stick, and the drain below it is not something you can see from above. Old putty hardens and can bond the flange to the tub, and mineral scale from Phoenix's hard water can add to it on old fittings. Do not take a hammer to it, and do not force a tool that is not gripping.

Underneath is the drain elbow, the overflow pipe and a tee, all sealed with gaskets. Kohler's retrofit guide warns that "Removing the existing overflow cover may effect the seal." It also tells you to provide access to the back of the bath and to inspect it for leaks afterward. Kohler's installation guide says that for replacement installations you remove the wall covering from the drain end of the bath and remove the existing drain. In other words, if the whole drain assembly needs replacing, the work moves to a wall or ceiling opening.

That matters in Phoenix. In a single-story home on a slab, the tub's drain and trap often sit in or under the concrete, so there may be no wall or ceiling to open from below. If the flange comes out but the drain elbow is cracked or the threads are stripped, that is a plumber's job, not a bigger wrench. And if your real problem is a slow tub, you may not need to remove anything. Why a bathtub won't drain covers cleaning the stopper and trap without pulling the flange, and what a P-trap is explains the water seal below.

Clean the opening, seat the new flange in sealant, tighten it, and fill the tub. Kohler's guide says to thoroughly clean the surface around the drain opening and the threads in the drain elbow, then dry fit the replacement flange, taking care not to cross thread it. Next, apply plumber's putty to the bottom of the flange, thread it into the drain elbow, and tighten it firmly with pliers.

Pick the sealant by material. Oatey's guide says to apply silicone sealant or plumber's putty to the bottom of the drain spud flange, and it adds, "Plumber's putty should never be used on ABS components." If your drain parts are ABS plastic, use silicone.

Test before you walk away. Kohler says to fill the bottom of the bath with water and check for leaks, then fill the tub the rest of the way and check again. Oatey's guide, for a full drain kit, says to fill the tub above the overflow inlet and confirm that all connections are watertight. Look underneath if you can. A drip you catch now costs a towel. One you miss can cost a ceiling.

Swapping a flange is a repair, and Phoenix's work-exempt list does not require a plumbing permit for repairing leaks in fixtures, as long as no valves, pipes or fixtures are replaced or rearranged. That same list says that if a concealed trap or drain pipe has to be removed and replaced with new material, it counts as new work that needs a permit and an inspection. Confirm the repair scope with Planning & Development before opening a wall.

Kohler's retrofit guide states that the retrofit should be performed by a qualified plumber, a fair sign of where the do-it-yourself line sits when you are changing the drain and overflow, not just the flange. Call a licensed plumber when the flange will not budge, when the drain elbow or overflow pipe is cracked or leaking, when you see a stain on the ceiling below an upstairs tub, or when the fix means cutting into a wall. A stain below the tub is worth checking right away, and a water leak from the ceiling walks through what to look at first. HQ Plumbing & Air offers 24/7 emergency service, is licensed and insured, and gives free estimates and upfront pricing.