Can I install a garbage disposal myself?

Yes, if you are comfortable making a simple wiring connection and there is already a disposal or a switched outlet under the sink. Replacing an existing disposal is squarely DIY — the mounting ring and drain connections are straightforward and the wiring is like-for-like. Installing a disposal where there was never one before is also DIY on the plumbing side, but it needs a dedicated switched, GFCI-protected circuit; if that circuit and switch do not exist, adding them is licensed electrical work. The disposal itself is about a 1 to 2 hour job.

Do I need an electrician to install a garbage disposal?

Only if the electrical supply is not already there. If you are replacing an old disposal, the wiring and switch already exist and you simply reconnect. If you are adding a disposal to a sink that never had one, you need a switched circuit under the sink — usually a dedicated 15- or 20-amp GFCI-protected circuit with a wall switch — and running that new circuit is a job for a licensed electrician in most jurisdictions and may require a permit. The plumbing side of a new install remains DIY.

Why does my new garbage disposal leak?

Trace it to one of three points. A leak at the top sink flange means the plumber's putty seal under the mounting ring was thin or the ring is not evenly tightened — re-seat it with a fresh, generous rope of putty. A leak at the dishwasher inlet or the discharge tube means a loose clamp or a missing gasket. And a leak from the bottom of the unit itself means the disposal is cracked or the internal seal has failed, which on a brand-new unit means a warranty return. Tighten and gasket the connections before suspecting the unit.

Do I need to remove the dishwasher knockout plug?

Yes — if your dishwasher drains into the disposal, you must punch out the knockout plug inside the disposal's dishwasher inlet before connecting the dishwasher hose, or the dishwasher will not drain and can back up and overflow. Tap the plug out with a screwdriver and a hammer and, critically, reach into the disposal and remove the loose plastic disc, or it will rattle and eventually block the drain. This is the single most commonly forgotten step on a garbage-disposal install.

How do I reset a garbage disposal that stops working after install?

Check the red reset button on the bottom of the unit first — press it in, as it trips if the motor was overloaded or bumped during install. If the disposal only hums but does not spin, the flywheel is jammed; turn the power off and use the hex wrench in the bottom socket to free it. If it is completely dead, confirm the wiring connection, the wall switch and the breaker. Most post-install failures are a tripped reset or a jam, not a bad unit.

How to Install a Garbage Disposal: DIY Step-by-Step

Written & researched by Priya Anand DIY & Tools Editor

Updated August 2026

Close-up detail of the material being worked in a diy plumbing project, in soft overcast light

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Installing a garbage disposal is a manageable DIY job — 1 to 2 hours, $80 to $250 for the unit, and no permit for a straight replacement. You mount the ring assembly to the sink flange, make a simple wiring connection, hang the disposal, and connect the drain and dishwasher hose. Replacing an old disposal is fully DIY. Adding one where none existed is DIY on the plumbing but needs an existing switched, GFCI-protected circuit — if that power is not there, an electrician runs it, and that part may need a permit.

We never buy, test or physically handle the products we rank; recommendations come from aggregated owner reviews and expert consensus, described in how we rank. More at the DIY plumbing hub.

How to Install a Garbage Disposal — Lowe's

Tools and materials

The disposal, plumber's putty, and the discharge tube and gaskets (usually included).
Screwdrivers, channel-lock pliers, a hacksaw (to trim the discharge tube), a wire nut or the included connector, and a voltage tester.
A bucket and towel, and the hex wrench that ships with the unit.
Basic hand tools — see best plumbing tools.

Overhead view of a person's hands tightening a fitting under a kitchen sink with a wrench, in soft overcast light

Step 1: Kill the power and remove the old unit

Turn off the breaker to the disposal circuit and verify with a voltage tester — this is the safety step you never skip. If replacing an old disposal, disconnect its drain and dishwasher hose, support the unit, and twist its mounting ring to drop it free. Disconnect the wiring inside the old unit's base plate. Remove the old sink flange and scrape off the old putty.

Step 2: Mount the new sink flange

Roll a rope of plumber's putty about a quarter-inch thick and press it under the lip of the new sink flange. Drop the flange into the sink drain hole and press it down so putty squeezes out evenly. From below, slide on the gasket, backup ring and mounting ring, and tighten the three screws evenly so the flange is pulled down snug and level. Wipe away the squeeze-out.

Overhead view of a person's hands tightening a fitting under a kitchen sink with a wrench, in warm evening lamplight

Step 3: Wire the disposal

Remove the plate on the bottom of the disposal. Feed the supply cable through the strain-relief connector, and join wire-to-wire: black to black, white to white, and the green or bare ground to the green screw. Cap each with a wire nut, tuck them in, and replace the plate. If your dishwasher drains into the disposal, knock out the dishwasher plug now with a screwdriver and hammer and remove the loose disc from inside — forget this and the dishwasher cannot drain.

Step 4: Hang the disposal and connect the drain

Lift the disposal to the mounting ring, align the three tabs, and turn to lock it on. Attach the discharge tube to the side outlet with its gasket, cutting it to length with a hacksaw so it meets the P-trap. Connect it to the trap and tighten the slip nuts hand-tight plus a nudge. Connect the dishwasher hose to the inlet and secure it with a clamp.

Close-up detail of the material being worked in a diy plumbing project, in warm late-afternoon light

Step 5: Restore power and test

Turn the breaker back on. Run cold water, switch on the disposal, and let it run for 20 seconds while you check every joint — the sink flange, the discharge connection, the P-trap and the dishwasher hose — for leaks. Run the dishwasher on a short cycle to confirm it drains through the disposal. Tighten anything that weeps.

Common mistakes

Forgetting the dishwasher knockout plug, so the dishwasher backs up.
Skimping on plumber's putty under the flange, causing a slow leak at the sink.
Not verifying power is off before wiring.
Uneven mounting-ring screws, leaving the flange tilted and leaking.
Leaving the loose knockout disc inside the disposal, where it blocks the drain.

When to call a pro

Call a licensed electrician if there is no existing switched, GFCI-protected circuit under the sink — running a new dedicated circuit is code-regulated and often permitted work. Call a plumber if adding a disposal requires reworking the drain height or trap arm to meet code, or if your local code prohibits disposals on a septic system (some do). A straight swap onto existing power and drain needs no permit.

How to Install a Garbage Disposal