Replace a Toilet Flange

A toilet flange is the fitting that connects your toilet to the drain pipe and anchors it to the floor. When it cracks, corrodes, or breaks—usually from years of pressure or overtightening—the toilet rocks, leaks at the base, or won't seal properly no matter how many wax rings you throw at it. The fix isn't complicated, but it requires working in tight quarters and making sure the new flange sits flush and secure. Do it right and you'll have a rock-solid toilet. Rush it and you'll be mopping up seepage within a week.

1. Empty and Disconnect. Shut off the water at the angle stop behind the toilet, flush to empty the tank, and sponge out remaining water from both tank and bowl. Disconnect the supply line, unscrew the closet bolts at the base, and lift the toilet straight up and off the flange. Set it on cardboard in the hallway.
2. Scrape Clean to Bare Metal. Use a putty knife to scrape all old wax from the flange and the bottom of the toilet horn. Get it completely clean—any leftover wax will compromise the new seal. Inspect the flange for cracks, rust-through, or broken bolt slots.
3. Cut Out the Old Flange. If it's a plastic flange, cut through it with an oscillating tool or hacksaw, working carefully to avoid damaging the pipe below. For cast iron, chisel out the lead or oakum joint if it's an old hub connection. PVC slip-fit flanges can sometimes be pried up after cutting the caulk bead. Pull out all screws or bolts anchoring it to the subfloor.
4. Verify Flush and Level. Dry-fit the replacement flange to confirm it sits flat on the subfloor and the pipe connection is snug. The flange top should be flush with or slightly above the finished floor—never below. If the pipe is too high, you may need a flange extender or offset flange. Check that the bolt slots align perpendicular to the wall.
5. Lock Flange to Floor. Apply PVC primer and cement if it's a glue-on flange, or tighten the compression ring if it's a twist-lock style. Once the pipe connection is set, drive stainless steel screws through the flange holes into the subfloor—at least four screws evenly spaced. Use screws long enough to bite into solid wood, not just the underlayment.
6. Set Bolts and Wax Ring. Drop new brass closet bolts into the flange slots and position them evenly. Press a new wax ring onto the flange, centered over the drain opening. If the flange sits low, use a wax ring with a plastic horn extension to make up the gap.
7. Lower Toilet, Compress Seal. Lift the toilet, align the holes in the base with the closet bolts, and lower it straight down onto the wax ring without rocking or twisting. Press firmly to compress the wax, then hand-tighten the nuts onto the bolts, alternating sides. Snug them down with a wrench but don't crank hard enough to crack the porcelain base.
8. Flush and Inspect. Hook up the supply line, turn the water back on, let the tank fill, and flush three times while watching the base for any seepage. Check the connection at the flange and around the bolt nuts. If it's dry after three flushes, trim the bolt threads with a hacksaw and cap them with plastic covers.