How to Install a Garbage Disposal, Step by Step

On this page (12 sections)

1. What should you check before buying installation parts?
2. What tools and drain kits do you need?
3. How do you prepare the sink and power?
4. How do you remove the old disposal?
5. How do you install a garbage disposal mount?
6. How do you connect the disposal to the drain?
7. How do you connect a dishwasher hose?
8. How do you connect power to a garbage disposal?
9. How do you check the installation for leaks?
10. What mistakes should you avoid after installation?
11. When should you call a plumber or electrician?
12. Which parts should you choose for your installation?

To install a garbage disposal, disconnect power, prepare the mount, secure the unit, and connect the drain and power in the order its manual requires. Check every plumbing joint for leaks before restoring power.

Before buying parts, compare the new unit’s mount, drain outlet height, and power connection with your current setup. Our garbage disposal buying guide covers unit choices, while these garbage disposal replacement checks help you plan a swap.

What should you check before buying installation parts?

Check the space, drain route, mount, and electrical connection first. A drain kit cannot fix a disposal that hangs too low for the wall drain or does not fit beneath the sink.

Measure from the sink bottom to the cabinet floor and note shelves, water filters, and other obstacles. Compare the new disposal’s dimensions and outlet position with the space available.

The drain needs a downhill route toward the wall connection without creating an improper trap arrangement. If the wall opening sits too high, get a plumber’s advice before choosing the unit.

Check whether the new disposal includes its mount, discharge elbow, and cord. Reuse an existing mount only when the new disposal’s instructions confirm compatibility.

Choose motor capacity separately from cabinet fit. Our guide to what size garbage disposal you need helps you compare household needs before committing to a model.

What tools and drain kits do you need?

Gather the disposal’s required tools and replace only the drain parts your layout needs. Have a bucket, towels, flashlight, measuring tape, and the hand tools named in the manual ready.

You may also need approved flange sealant, replacement fittings, and a compatible power cord. Confirm these needs before taking apart a working sink.

The PF WaterWorks kit suits a job where several drain sections need replacement. It contains 1-1/2 in OD polypropylene components, including 6 in and 14 in flanged tailpieces, a drain arm, tee, elbow, trap, connection boot, and washers.

Skip a full kit if your existing pipes are sound and only one fitting needs replacement. Compare the required pipe lengths and joint types with the included pieces before buying.

Choose PlumbCraft when you need to shorten plastic drain sections to fit the cabinet layout. It works with standard plastic or chrome-plated brass drain systems using 1-1/2 in OD piping.

Its tailpieces, waste arm, and wall tube can be cut after measuring. Skip it when your job needs only a disposal outlet elbow or when the required connections do not match.

These are drain kits, not replacements for the disposal’s sink mount or electrical parts. Photograph your existing plumbing before removal so you can compare the route and connections during assembly.

How do you prepare the sink and power?

Switch off the disposal’s circuit at the breaker before disconnecting anything. The wall switch alone does not isolate the electrical supply.

Unplug a cord-connected disposal after switching off the breaker. For hardwired equipment, have a qualified person verify that the wiring is de-energized with an appropriate voltage tester before disconnecting it.

Clear the cabinet and place a bucket beneath the trap. If your tools or body could strike nearby water supply valves or hoses, shut off those supplies too.

Support the disposal before loosening its plumbing. Disconnect the dishwasher hose if present, then release the drain connections while leaving the mount secured.

How do you remove the old disposal?

Support the unit’s weight before releasing its mounting mechanism. Use a helper if you cannot safely hold it while operating the mount.

Follow the old disposal’s removal instructions and lower it carefully into the cleared cabinet. Do not let it hang from the drainpipe, dishwasher hose, or wiring.

Remove the sink flange and mounting assembly if the replacement requires new hardware. Clean off old putty or sealant without scratching the sink, then inspect the opening for damage.

Keep the removed elbow and hardware nearby for comparison. If replacement is still undecided, read about a disposal that hums but does not spin before treating a jam as a failed motor.

How do you install a garbage disposal mount?

Fit the flange and mounting hardware in the exact order shown in your model’s manual. The sink seal and the mechanical mount perform different jobs, and both must be secure.

Use plumber’s putty or another sealant only when approved for the disposal and sink material. Do not assume putty is suitable for every stone or composite sink.

Keep the flange centered while fitting the parts beneath the sink. Tighten the mounting hardware evenly as directed, then remove excess sealant.

How to install a garbage disposal in the right order

Prepare any connections that become hard to reach before hanging the disposal. Depending on the model, this may include the electrical connector, discharge assembly, or dishwasher inlet.

Lift the unit into place and engage the mounting mechanism fully. If the design allows rotation, position the drain outlet toward the plumbing before completing the final locking step.

How do you connect the disposal to the drain?

Align the drain fittings without pulling them into place with the nuts. Forced connections can leave washers crooked and put strain on the disposal outlet.

The Mr. Scrappy kit suits a missing or damaged outlet assembly when the remaining drain plumbing is usable.

It includes a PVC elbow, flange, rubber gasket, and 2 screws.

Confirm the outlet shape, screw spacing, and drain connection fit against your disposal’s requirements. Skip this kit if you need a full trap arrangement or cannot confirm the mounting fit.

Dry-fit the pipes before cutting anything. Mark the needed lengths with enough pipe left to seat properly inside each joint, then make straight cuts and remove burrs.

Place each washer in the direction required by the fitting instructions. PlumbCraft directs you to hand-tighten its plastic nuts; using a wrench can damage them.

Keep the trap accessible for future cleaning. Do not use thread tape as a substitute for a missing or poorly seated slip-joint washer.

How do you connect a dishwasher hose?

Remove the disposal’s dishwasher inlet knockout only if a dishwasher hose will connect there. Retrieve the loose plug from inside the disposal before use.

Attach the hose with the correct clamp and follow the dishwasher manual’s routing instructions. Local rules may require an air gap; a high loop is not a substitute where an air gap is required.

Leave the knockout intact when no dishwasher connects to the disposal. A forgotten knockout can prevent dishwasher drainage, while an unused open inlet can leak.

How do you connect power to a garbage disposal?

Use the connection method approved for your exact disposal. A cord kit must match the unit, and a plug-in setup requires a suitable grounded outlet within reach.

The InSinkErator EZ Connect cord suits compatible Power Series and Advanced Series continuous feed models. Its connector inserts into the disposal’s bottom, and the kit includes a ground screw and instructions.

Skip it for other models, including units whose cord connection requires a different assembly. Check how garbage disposal power cords work before selecting an electrical accessory.

Follow the manual for grounding, connector security, and cover installation. Keep the cord clear of sharp edges and strained connections, and do not stretch it to reach an outlet or use an extension cord.

Have an electrician handle new outlets, circuit changes, or hardwired connections you cannot complete correctly. Leave the breaker off until the full installation is secure.

How do you check the installation for leaks?

Check the plumbing with water while power remains disconnected. Dry the cabinet and all joints first so new moisture is easy to spot.

Confirm that the disposal is locked onto its mount and that drain connections and hose clamps are secure. Run water, then fill and release some sink water to check the joints under a larger flow.

Inspect the sink flange, disposal outlet, trap, and wall connection. Press a dry paper towel against each joint to help find slow drips.

Correct any leak before restoring power. Once everything is dry and secure, run cold water and briefly operate the disposal according to its manual.

Check again after operation and after the dishwasher drains, if connected. Disconnect power before adjusting any fitting or hose.

What mistakes should you avoid after installation?

Use the disposal for small food scraps and keep grease out of the drain. Feed scraps gradually with cold water running, following the unit’s instructions.

Keep bones, fibrous scraps, and other restricted materials out according to your model’s manual. Never put your hand inside the grinding chamber, even when the wall switch is off.

Do not repeatedly reset a unit that hums or stops. Disconnect power and follow the manual’s jam-clearing steps before trying again.

Clean the accessible splash guard and sink opening as directed. Our guide to cleaning a garbage disposal explains a practical care routine.

When should you call a plumber or electrician?

Get professional help when the drain cannot align correctly, the sink mount is damaged, or the electrical work exceeds your skills. Persistent leaks also need correction before normal use.

A direct replacement with matching connections is a simpler DIY job than adding a disposal to a sink without one. New wiring, a high wall drain, or major pipe changes can turn the job into several separate tasks.

Consider the old unit’s condition before buying repair parts. Read how long a garbage disposal lasts if age and repeated problems affect the decision.

Which parts should you choose for your installation?

Choose a full drain kit for several missing fittings, an elbow kit for an outlet repair, and a cord only after confirming compatibility. Knowing how to install a garbage disposal starts with buying parts that match the actual job.

Pick PF WaterWorks for a broader drain rebuild or PlumbCraft when its cut-to-fit sections suit your layout. Choose the Mr.

Scrappy elbow kit only for a matching outlet assembly, and reserve the InSinkErator cord for compatible EZ Connect models.

Before ordering electrical parts, review your garbage disposal power cord options. Resolve fit, drainage, and power questions before removing the old unit.