Replacing an InSinkErator disposal takes two to four hours and requires only basic tools

You can replace your InSinkErator garbage disposal yourself if you are comfortable working under the sink and handling plumbing connections. The job involves disconnecting the old unit, unbolting it from the sink, installing a new one in its place, and reconnecting the drain and electrical lines. Most homeowners with a wrench, screwdriver, and adjustable pliers can do this without calling a plumber.

The hardest part is usually breaking loose the old mounting ring that holds the disposal to the sink — it can be stuck tight. The electrical connection is straightforward: you either plug the new disposal into an outlet or wire it to a switch, depending on how your old one was set up. If you have never done plumbing work before, the drain connections are straightforward PVC or metal pipes that hand-tighten with a wrench.

Key Takeaways

  • Turn off the breaker or unplug the old disposal before you touch anything, and never reach into the sink opening while power is on.
  • The mounting ring holding the disposal to the sink requires a special wrench or a flathead screwdriver and hammer to loosen — do not skip this step or you will strip the bolts.
  • Take a photo of the drain connections before you disconnect them so you know which pipes go where when you reassemble.
  • The new disposal must be the same mounting type as your sink opening — InSinkErator makes three-bolt and EZ-Mount versions, and they are not interchangeable.
  • If your old disposal was hardwired to a switch, the new one must be too; if it was plugged in, the new one should be plugged in the same way.

What you need before you start

Gather these tools and materials before you go under the sink: an adjustable wrench, a flathead screwdriver, a hammer, a bucket or towel to catch water, a flashlight, and the new InSinkErator unit. Check the box to confirm it matches your mounting type — look at the bottom of your old disposal to see if it has three bolts around the edge (three-bolt mount) or a smooth collar (EZ-Mount). InSinkErator makes both, and they do not fit the same sink opening.

You will also need plumber's putty if your sink does not have a rubber gasket already installed, and you may need a new drain tailpiece or coupling depending on the condition of your old pipes. Have a bucket or old towel ready — there will be standing water in the trap under the sink, and it will spill when you disconnect the pipes.

Turn off power and disconnect the old disposal

If the disposal is plugged into an outlet, unplug it. If it is hardwired to a switch, go to your electrical panel and turn off the breaker labeled for the kitchen or disposal — flip it all the way to the off position. Wait 30 seconds, then go back to the sink and try to turn on the switch to confirm power is off. Never work on the disposal while power is on, even if you think it is off.

Place a bucket under the trap (the U-shaped pipe under the sink) and loosen the slip nuts on both ends with your adjustable wrench. The trap will drain into the bucket. Once the trap is loose, disconnect the dishwasher hose if one is attached to the disposal — it usually clips or bolts to the side. Then disconnect the drain tailpiece (the straight pipe coming down from the sink) from the disposal by loosening the slip nut where they meet.

Remove the mounting ring and old disposal

The disposal hangs from a mounting ring bolted to the sink opening. Look up into the sink from underneath and you will see three bolts (or a smooth collar for EZ-Mount) holding the ring in place. For a three-bolt mount, use your flathead screwdriver and hammer to tap each bolt counterclockwise — do not try to turn them by hand first, as they are usually very tight. Tap gently and work around the ring, loosening each bolt a little at a time so the ring comes off evenly.

Once all three bolts are loose, unscrew them by hand and set them aside. The mounting ring will drop, and the old disposal will hang from it. Support the disposal with one hand and unscrew the ring from the disposal body. Set the old unit aside. For EZ-Mount disposals, twist the collar counterclockwise by hand until it releases — no tools needed.

Install the mounting ring on the new disposal

If your new disposal came with a mounting ring, screw it onto the disposal body by hand until it is snug — do not overtighten. The ring should sit flush against the disposal. If you are reusing the old ring (which is common), make sure it is clean and free of old putty or debris. Screw it onto the new disposal the same way.

Before you lift the new disposal into place, check that the rubber gasket is seated properly in the sink opening. If your sink does not have a gasket, roll a rope of plumber's putty and press it around the underside of the sink opening to create a seal. This prevents water from leaking between the sink and the disposal.

Bolt the new disposal to the sink

Lift the new disposal into position under the sink so the mounting ring aligns with the three bolt holes in the sink opening. Insert the three bolts through the holes and hand-tighten them. Then use your flathead screwdriver and hammer to tap each bolt clockwise, working around the ring to tighten evenly. Tighten until the ring is snug against the sink — you should feel resistance, but do not force it or you will crack the sink or strip the bolts.

Once the ring is tight, the disposal should hang solidly from the sink with no wobble. If it moves or tilts, loosen the bolts slightly, reposition the ring, and tighten again. A properly installed disposal will not move when you push on it from below.

Reconnect the drain pipes and dishwasher hose

Reconnect the drain tailpiece (the pipe from the sink) to the disposal outlet by hand-tightening the slip nut. Use your wrench to snug it — you want it tight enough that it does not leak, but not so tight that you cannot loosen it later if you need to. Reconnect the trap by hand-tightening both slip nuts, then use your wrench to snug them. If your old dishwasher hose is still attached, clip or bolt it back to the disposal.

Before you turn on the water, place a bucket under the trap and run the sink for 10 seconds. Check for leaks at all three connection points: the tailpiece, both trap nuts, and the dishwasher hose if present. If water drips, tighten the nut a quarter turn and test again. Do not over-tighten — a small drip usually means the washer inside the nut has shifted, and a quarter turn will fix it.

Reconnect the electrical power

If your old disposal was plugged into an outlet, plug the new one in the same outlet. If it was hardwired to a switch, you will need to connect the electrical wires. The disposal will have a power cord with a plug on the end — you can either plug it into an outlet under the sink, or you can have an electrician hardwire it to the switch. Most new installations use a plug for safety and simplicity.

If the old disposal was hardwired and you want to keep it that way, turn off the breaker, disconnect the old wires from the disposal, and connect them to the new disposal using wire nuts. Match the colors: black to black, white to white, and bare copper to bare copper. If you are not confident with electrical connections, plug the disposal into an outlet instead — it is safer and easier.

Test the new disposal

Turn the breaker back on or confirm the plug is in the outlet. Turn on the cold water and flip the disposal switch. Let it run for 10 seconds, then turn it off and check under the sink for leaks. If everything is dry, run the water again and drop a few ice cubes down the drain to test the grinding. The disposal should sound normal — a grinding noise is fine, but a loud rattling or metal-on-metal sound means something is wrong and you should turn it off when ready.

Once you confirm there are no leaks and the disposal runs smoothly, you are done. The whole job usually takes two to four hours the first time. If you run into a stuck bolt or a leak that will not stop, it is worth calling a plumber rather than forcing something and causing damage.

Frequently Asked Questions

Can I install a different brand of disposal in my InSinkErator sink opening?

Yes, but only if the new disposal uses the same mounting type. Most standard three-bolt disposals fit any three-bolt sink opening, regardless of brand. However, EZ-Mount disposals only fit EZ-Mount openings. Check your sink opening before you buy a replacement — if you have three bolt holes, you can use any three-bolt disposal; if you have a smooth collar, you need an EZ-Mount unit.

What if I cannot loosen the mounting ring bolts?

explore penetrating oil (like WD-40) around the bolts and let it soak for 15 minutes. Then tap the screwdriver gently with the hammer, working around the ring. If the bolts still will not budge, you may need to cut the disposal away from the ring using a reciprocating saw or hacksaw — this is when calling a plumber saves time and frustration.

Do I need a plumber to hardwire the new disposal to a switch?

If your old disposal was hardwired, a licensed electrician should do the same for the new one. Electrical work under the sink requires proper grounding and connections that are code-compliant. Plugging the disposal into an outlet is simpler and safer if you are not experienced with wiring.

Why is water leaking from the connection where the drain pipe meets the disposal?

The rubber washer inside the slip nut has shifted or worn out. Tighten the nut a quarter turn with your wrench. If it still leaks, turn off the water, loosen the nut completely, remove the old washer, and replace it with a new one from a hardware store — they cost less than a dollar.

Can I run the disposal without water?

No. Always run cold water while the disposal is on. Water cools the motor and helps move ground food down the drain. Running it dry can damage the motor and create a fire hazard.