A garbage disposal replacement takes two to four hours and costs $150 to $500 in parts, depending on the model you choose

Replacing a garbage disposal is a plumbing job you can do yourself if you are comfortable working under a sink and have basic tools. The disposal itself is not difficult to remove or install — the real work is disconnecting the old plumbing lines and reconnecting new ones without leaks. If you have never done this before, budget extra time and keep a bucket under the sink while you work.

You will need to turn off power at the breaker, drain the sink completely, and disconnect three things: the drain line from the sink, the discharge pipe going to the wall, and the electrical connection. Then you reverse the process with the new unit. The hardest part is usually breaking the seal on the old disposal or getting the new one to sit flush against the sink flange.

Key Takeaways

  • Turn off the breaker that powers the disposal before you touch anything, and test the outlet with a voltage tester to confirm power is off.
  • You will need a bucket, adjustable wrench, screwdriver, flashlight, and plumber's putty or silicone caulk — most people already own these.
  • The disposal hangs from a mounting ring under the sink; you loosen three bolts to drop it out, then install the new one by tightening the same bolts.
  • The discharge pipe and drain line are held on with hose clamps that you loosen by hand or with a screwdriver — they do not require special tools.
  • If you are not confident with plumbing connections, a plumber can do this job in under an hour for $200 to $400 in labor.

What you need before you start

Gather your tools and materials in one place. You will need an adjustable wrench (or two), a screwdriver (both Phillips and flathead), a flashlight, a bucket, and old towels or rags. Have plumber's putty or silicone caulk on hand — you will use this to seal the sink flange where the new disposal connects.

Buy the replacement disposal before you start. Disposals come in half-horsepower (basic, quiet, slower) and three-quarter or one-horsepower (faster, louder, more expensive). Most homes use half-horsepower. Check your old disposal's nameplate or manual to see what you had, or ask at the hardware store what fits your sink. Bring the old unit's model number if you have it.

Turn off the breaker that controls the disposal. If you do not know which one, turn off the main breaker. Once the breaker is off, plug in a lamp or phone charger into the outlet under the sink to confirm there is no power. A voltage tester is safer — touch it to the outlet and it will beep if power is still on.

Remove the old disposal

Place a bucket under the sink to catch water and debris. Loosen the hose clamp that connects the drain line (the pipe coming from the sink strainer) to the disposal. You can usually loosen this by hand or with a screwdriver — turn the screw counterclockwise until the clamp is loose enough to slide off. Pull the drain line away from the disposal.

Loosen the hose clamp on the discharge pipe (the line going to the wall or drain). This is usually lower and to the side. Slide this pipe off as well. Some water will drip — that is normal.

Locate the three bolts that hold the mounting ring to the sink flange. These are under the sink, spaced evenly around the disposal. Use your wrench to turn each bolt counterclockwise. As you loosen them, the disposal will start to drop. Support it with your other hand so it does not fall suddenly. Once all three bolts are loose, the disposal will come free. Set it aside.

Disconnect the electrical connection. There is usually a plug under the sink, or the wires are connected with wire nuts. If there is a plug, unplug it. If there are wire nuts, unscrew them by hand and separate the wires. If you are unsure, take a photo before you disconnect anything.

Prepare the sink flange for the new disposal

The sink flange is the metal ring that sits on top of the sink opening. It is held in place by plumber's putty or caulk. Scrape away the old putty with a flathead screwdriver or putty knife. Get it as clean as you can — dried putty will prevent the new disposal from sealing properly.

Wipe the flange clean with a damp cloth and let it dry. If the flange is corroded or damaged, you may need to replace it, but this is rare. Most flanges last the life of the house.

Install the new disposal

Apply a bead of plumber's putty or silicone caulk around the underside of the sink flange. Press the new disposal up into place, aligning the three bolt holes. Hand-tighten the three bolts first, then use your wrench to tighten them evenly — do not over-tighten, or you will crack the flange. Tighten a little on each bolt, then move to the next, so the pressure is even.

Reconnect the drain line from the sink to the disposal. Slide the hose clamp over the connection and tighten it with your screwdriver. It should be snug but not so tight that you strip the screw.

Reconnect the discharge pipe to the disposal outlet. Again, use the hose clamp to secure it. Make sure both pipes are angled slightly downward so water flows toward the drain, not back toward the disposal.

Reconnect the electrical connection. If there was a plug, plug it in. If there were wire nuts, match the wires (usually black to black, white to white, and bare copper to bare copper or green), twist them together, and screw the wire nuts back on. If you are unsure about electrical connections, have a plumber do this step.

Test the new disposal

Turn the breaker back on. Run cold water into the sink for 30 seconds, then turn on the disposal. Let it run for a few seconds while water is flowing. Listen for unusual noises and watch under the sink for leaks.

Check both hose clamps while the disposal is running. If you see water dripping from either connection, turn off the disposal and tighten the clamp a little more. It is normal for a small amount of water to be present under the sink, but it should not be actively dripping.

Run the disposal a few more times over the next day to make sure everything is working. If you notice a leak that does not stop after tightening the clamp, the hose may be cracked or the connection may need to be redone. At that point, it is worth calling a plumber rather than guessing.

When to call a plumber instead

If the old disposal is stuck and will not come out, or if the mounting bolts are corroded and will not turn, a plumber has tools to handle this without damaging the sink. If you are not comfortable working with electrical connections, a plumber can do the whole job safely. If water backs up into the sink after installation, the discharge line may be blocked or misaligned — this is also a plumber's call.

A plumber can usually replace a disposal in under an hour. Labor typically runs $200 to $400 depending on your area and how difficult the old unit is to remove. If you are renting, check your lease — some landlords require a licensed plumber to do this work.

Frequently Asked Questions

Do I need to turn off the water to replace a disposal?

No, you do not need to turn off the main water supply. You do need to turn off the breaker that powers the disposal and make sure the sink is empty before you start. Have a bucket ready to catch water that drains from the pipes when you disconnect them.

Can I install a new disposal if my old one is jammed or broken?

Yes. A broken or jammed disposal still comes out the same way — you disconnect the pipes and loosen the mounting bolts. The disposal does not need to work to be removed. If it is truly stuck, a plumber can help, but most come out with patience and the right wrench.

What if I have a septic system instead of a sewer line?

You can still use a garbage disposal, but be more careful about what goes into it. Avoid putting grease, bones, or fibrous foods down the drain — these can clog your septic tank faster than they would a municipal sewer. The installation process is the same regardless of what your drain line connects to.

How do I know if the new disposal is the right size for my sink?

Most kitchen sinks have a standard 3.5-inch opening, and disposals are designed to fit this. Before you buy, check your old disposal's model number or measure the opening. If you are unsure, bring a photo to the hardware store or ask the salesperson — they see this question every day.

Is it normal for the disposal to leak a little after installation?

A small amount of moisture under the sink is normal, but active dripping is not. If you see water running down the pipes while the disposal is on, tighten the hose clamps. If tightening does not stop it, the hose may be cracked or the connection may need to be redone — call a plumber at that point.