A leaking or damaged garbage disposal flange is a common plumbing issue. This guide will show you how to remove the old flange so you can install a new one and stop the leak for good.
Understanding the Garbage Disposal Mounting System
First, know that the flange is not part of your sink -- it is a separate component of a mounting system that holds the disposal unit beneath the sink. Most modern disposals, especially InSinkErator models, use a quick-mount system with three main parts:
- The Sink Flange: The visible part in the sink drain.
- The Mounting Ring/Collar: An assembly that locks onto the flange from below.
- The Disposal Unit: Attaches to the mounting ring.
Tools and Materials You Will Need
- Channel-lock pliers or an adjustable wrench
- Flat-head screwdriver
- Putty knife
- Bucket and rags
- Optional: Hairdryer or heat gun (for stubborn flanges)
- For reinstallation: New sink flange gasket or plumber's putty, new snap ring (if applicable)
Two Methods for Flange Removal
| Method | Best For | Key Tools | Core Concept |
|---|---|---|---|
| Standard Split Ring Method | Standard InSinkErator-style mounts where a snap/split ring is visible | Screwdriver, Pliers | Prying off a retaining ring to release the flange |
| Stubborn Flange Method | Flanges sealed with old, hardened plumber's putty or sealant that won't twist loose | Heat gun, Pliers, Putty knife | Applying gentle heat to soften the sealant for removal |
Method 1: The Standard Split Ring Removal
Disconnect and Remove the Disposal Unit
Turn off power and water. Disconnect the drain pipes and electrical connection. Rotate the mounting collar to unlock and lower the disposal unit from the mounting assembly.
Locate the Snap Ring
Look up at the mounting assembly from under the sink. You will see a large plastic or metal ring (the mounting ring) held by three screws. Above it, you should see a black rubber or metal split ring snapped into a groove on the underside of the sink flange.
Pry Off the Split Ring
Insert a flat-head screwdriver under the split ring and carefully pry it out of its groove. It may pop off. Keep a hand on it so it does not fall.
Remove the Mounting Ring
Unscrew the three mounting screws and remove the entire mounting ring/collar.
Remove the Flange
From above the sink, the flange should now be free. You may need to twist it or gently tap it from below with a wooden block to break the old sealant's hold.
Method 2: Removing a Stubborn, Sealed Flange
Follow Steps 1-2 Above: Remove the disposal and mounting assembly to isolate the sink flange.
Apply Heat: From under the sink, carefully use a hairdryer or heat gun to warm the metal of the sink flange and the sink basin around it. Do not overheat or use an open flame. The goal is to soften the decades-old plumber's putty, not melt the sink.
Twist and Remove: While the metal is warm (wear gloves), try to twist the flange from above. Work it back and forth while pulling up. You can also gently tap it upward from below with a wooden block.
Clean the Sink Hole: Once removed, use a putty knife to scrape all old putty and sealant from the sink drain hole.
How to Install a New Flange
Apply New Sealant
Roll a 1/2-inch diameter rope of plumber's putty and place it under the rim of the new sink flange. Alternatively, use the provided rubber gasket.
Insert the Flange
Push the flange down into the drain hole from above. From below, thread on the mounting ring and gasket (if separate).
Tighten and Secure
Have a helper hold the flange steady from above while you, from below, screw the three mounting bolts evenly and snugly. Do not overtighten.
Finalize
Wipe away the excess putty that squeezes out around the flange. Reattach your disposal unit following the manufacturer's instructions.
Frequently Asked Questions
Do I always need to replace the sink flange when replacing the disposal?
No. If your flange is in good condition, not corroded, and compatible with the new disposal's mounting system, you can reuse it.
What's better -- plumber's putty or a rubber gasket?
For sink flanges, a generous bead of plumber's putty is the traditional and highly recommended method. It creates a superior, moldable seal that fills imperfections better than a rubber gasket.
The disposal is removed, but I can't see a split ring. What now?
Your model may use a different system. Look for a large locking nut or a ring with setscrews. Consult your unit's manual. The general principle is the same: dismantle what's holding the mounting assembly from below.
Is it safe to use a heat gun under my sink?
Yes, if done with caution. Use a low setting, keep it moving, and avoid pointing it at electrical lines, plastic pipes, or the sink's finish. A hairdryer is a safer, lower-heat option.
My flange is turning but won't come up. Why?
You've likely unscrewed it from the mounting collar, but the old plumber's putty is still acting like glue. Apply gentle heat from below to soften the sealant.
Conclusion
Removing a garbage disposal flange is a manageable DIY task with the right tools and approach. The key is identifying your mounting system -- most modern disposals use a split ring that can be pried off with a screwdriver, while stubborn, older flanges may require gentle heat to loosen hardened sealant. The most common reason for a leak after the job is improper sealing, so use a generous rope of fresh plumber's putty and tighten the mounting bolts evenly.
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