What a shower drain flange is and why it fails
The shower drain flange is the metal or plastic ring that sits on top of your drain pipe, under the shower floor. It holds the drain strainer basket in place and seals the gap between the pipe and the floor material — tile, acrylic, or fiberglass. When water leaks around the drain instead of down it, or when the flange cracks or rusts, you need to replace it.
Flanges fail because of age, corrosion from standing water, or damage during installation. If your shower is over 15 years old, the flange is likely corroded even if it is not visibly broken. A leaking flange sends water into the subfloor, which causes rot and mold — problems that cost far more to fix than the flange itself.
Replacing the flange is a weekend job if you have basic tools and the drain is accessible from below. If your shower is on an upper floor with no basement or crawl space underneath, or if the flange is glued to the pipe, the job becomes harder and may require a plumber.
Key Takeaways
- A shower drain flange is the ring that holds the strainer basket and seals the drain opening; it sits directly on top of the drain pipe under your shower floor.
- You can replace the flange yourself if you can access the drain from below — from a basement, crawl space, or by removing the ceiling in the room below.
- The job requires a pipe wrench, a screwdriver, plumber's putty or silicone caulk, and a new flange that matches your pipe diameter (usually 2 inches).
- If the flange is solvent-welded to the pipe, you will need to cut the pipe and install a new section with a slip-fit coupling, which is more involved than an unglued flange.
- After installation, seal the flange with plumber's putty or caulk and let it cure fully before running water, usually 24 hours.
Determine whether you can access the drain from below
Before you buy a flange, find out whether the drain is reachable. Go to the room directly below your shower — a basement, crawl space, or the floor below. Look up at the underside of the floor. You should see the drain pipe coming down through the floor. If you can see it and reach it, you can do this job yourself.
If there is no space below — if your shower is on a second or third floor with no attic or crawl space, or if the floor is solid concrete — you have two options. You can cut a hole in the ceiling of the room below to access the drain, which means patching drywall afterward. Or you can remove the shower floor from above, which requires breaking out tile or cutting through acrylic, then replacing it. Both routes are more work than accessing from below.
If you cannot access the drain at all, or if the flange is glued to the pipe with solvent cement, hire a plumber. Cutting and replacing the pipe section requires solvent-welded PVC work, which is beyond a basic replacement.
Gather tools and materials
You will need a pipe wrench (adjustable wrench works if the flange has a nut), a screwdriver (usually Phillips), plumber's putty or silicone caulk, and a replacement flange. The flange must match your pipe diameter — measure the pipe or bring a photo to the hardware store. Most residential showers use 2-inch PVC pipe.
Buy a flange rated for your pipe material. PVC flanges fit PVC pipe, cast iron flanges fit cast iron pipe. If you are unsure, take a photo of the pipe and the existing flange to the store. Also pick up a new strainer basket if yours is corroded or damaged — they cost $10 to $20.
Have a bucket or towel ready. Even though the trap below holds water, some will spill when you remove the old flange.
Remove the old flange and strainer basket
From above, unscrew the strainer basket. It usually has a Phillips screw in the center. Once the screw is out, the basket lifts away. Set it aside.
Go below and locate the flange nut — the large nut that holds the flange to the pipe. Use the pipe wrench to turn it counterclockwise. It will be tight. Once the nut is loose, you can usually unscrew it by hand. As you unscrew it, water from the trap will drip into your bucket.
Once the nut is off, the flange will slide up and off the pipe. If it is stuck, tap it gently with a hammer from below. Scrape off any old putty or caulk from the top of the pipe with a putty knife. The pipe surface must be clean for the new flange to seal.
Install the new flange
Slide the new flange onto the pipe from below. Make sure the flange sits flat against the underside of the shower floor. The flange should rest on the floor material — tile, acrylic, or fiberglass — not float above it.
Thread the nut back onto the pipe and tighten it with the pipe wrench. Tighten firmly but do not over-tighten; you want the flange snug against the floor, not crushed. The nut should be hand-tight plus a quarter turn with the wrench.
From above, the flange should now sit flush with the shower floor. If there is a gap between the flange and the floor, go back below and tighten the nut a bit more.
Seal the flange and reinstall the strainer basket
The gap between the flange and the shower floor must be sealed to prevent water from leaking down around the pipe. Use plumber's putty or silicone caulk. Putty is easier to work with and can be removed later if you need to access the flange again. Caulk is more permanent and better for tile.
If using putty, knead it in your hands until it is soft, then press it into the gap all the way around the flange. Smooth it with your finger. If using caulk, run a bead around the flange and smooth it with a wet finger or caulk tool.
Let the putty or caulk cure for 24 hours before running water. Once it is dry, screw the strainer basket back in place and test the drain. Water should flow straight down without leaking around the flange.
What to do if the flange is glued to the pipe
If the old flange will not unscrew — if it is solvent-welded to a PVC pipe — you cannot straightforward slide a new one on. The pipe itself must be cut and replaced. This requires a hacksaw, a slip-fit coupling (a short connector that joins two pieces of pipe without glue), and solvent cement to glue the coupling in place.
Mark the pipe about 2 inches below the flange. Cut through the pipe with a hacksaw at that mark. Remove the section with the old flange attached. Dry-fit the slip coupling onto the lower pipe section to make sure it slides on smoothly. Then explore solvent cement to both the pipe and the inside of the coupling, slide the coupling on, and hold it for 30 seconds. Let the cement cure for 24 hours before installing the new flange.
If you are not comfortable with solvent cement work, this is the point to call a plumber. A plumber can do this in an hour and charge $150 to $300 depending on location.
Frequently Asked Questions
Can I replace the flange from above without accessing the drain below?
No. The flange nut is on the underside of the pipe, below the floor. You must reach it from below to unscrew it. If you cannot access the drain from below, you will need to cut a hole in the ceiling of the room below or remove the shower floor from above.
What size flange do I need?
Most residential shower drains use 2-inch PVC pipe, so a 2-inch flange. Measure the outside diameter of your drain pipe or bring a photo to the hardware store. The flange must match the pipe diameter exactly.
How long does the putty or caulk need to cure?
Plumber's putty typically cures in 24 hours. Silicone caulk also takes 24 hours. Do not run water or use the shower until the sealant is fully cured, or water will seep around the flange and defeat the purpose of the replacement.
What if water still leaks around the flange after I replace it?
The sealant may not be fully cured, or the flange may not be sitting flat against the floor. Wait 24 hours and test again. If it still leaks, go below and check that the flange nut is tight. If the flange is tilted or the nut is loose, tighten it and re-seal the gap.
Do I need to replace the strainer basket too?
Not necessarily. If the old basket is not corroded or damaged, you can reuse it. But if it is rusty, cracked, or does not fit snugly in the new flange, buy a replacement. They are inexpensive and come in standard sizes.