Install a Garbage Disposal Unit
Created by Cheli
Step-by-step guide to safely install a garbage disposal under a kitchen sink.
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Checklist Items (22)
Gather tools and materials and ensure safety
Collect all necessary tools (adjustable wrench, screwdriver, pliers, bucket) and materials (mounting assembly, plumber's putty, electrical wire nuts). Turn off power at the breaker and shut off water supply valves.
Turn off power at the circuit breaker
Locate the breaker controlling the disposal circuit and switch it to OFF. Verify with a non-contact voltage tester.
Shut off water supply
Close the hot and cold water shut-off valves under the sink. Open the faucet to relieve pressure.
Gather tools and materials
Assemble adjustable wrench, screwdriver set, pliers, bucket, plumber's putty, mounting assembly, discharge tube, dishwasher inlet hose (if applicable), wire nuts, and electrical cable.
Review safety precautions
Wear safety glasses and gloves. Ensure work area is well-lit and keep children and pets away.
Check for existing wiring condition
Inspect the electrical cable for damage; replace if frayed or cracked.
Ensure proper ventilation
If working in a confined space, open windows or use a fan to avoid inhaling fumes from putty or solvents.
Remove existing garbage disposal unit
If replacing an old unit, disconnect and remove it before installing the new one.
Disconnect discharge tube
Loosen the clamp on the discharge tube and detach it from the disposal outlet.
Disconnect dishwasher inlet (if applicable)
If a dishwasher hose is connected, loosen the clamp and detach it.
Unmount the disposal
Rotate the mounting ring counterclockwise to release the unit from the mounting assembly, then lower it out of the sink.
Clean and prepare the sink flange opening
Remove old putty, clean the sink hole, and ensure the surface is smooth for a watertight seal.
Remove old plumber's putty
Scrape away any remaining putty with a putty knife; wipe the area clean.
Check flange fit
Insert the new flange into the sink hole to verify it sits flush; adjust if needed.
Install the mounting assembly
Attach the mounting ring and support bracket to the sink flange according to manufacturer instructions.
Apply plumber's putty
Roll a rope of plumber's putty and press it into the sink hole around the flange.
Insert flange and secure
Press the flange into the putty, then from underneath attach the mounting ring and tighten the bolts evenly.
Attach support bracket
Snap the support bracket onto the mounting ring and ensure it locks securely.
Make plumbing connections
Connect the discharge tube and dishwasher inlet (if present) to the disposal.
Attach discharge tube
Slide the discharge tube onto the disposal outlet and secure with the clamp; tighten with a screwdriver.
Connect dishwasher inlet (if applicable)
If you have a dishwasher, attach its hose to the disposal's inlet port and tighten the clamp.
Check for leaks
Turn water supply back on briefly and run water to check for leaks at all connections; tighten as needed.
Wire the garbage disposal
Connect the disposal's electrical wires to the house circuit following local code.
Connect ground wire
Attach the bare copper ground wire from the disposal to the ground wire in the wall box using a wire nut.
Connect hot and neutral wires
Match the black (hot) to black and white (neutral) to white, securing each with wire nuts; fold wires neatly into the box.
Mount the disposal unit onto the assembly
Lift the disposal and twist it onto the mounting ring until it locks.
Secure locking ring
Turn the mounting ring clockwise to lock the unit in place; ensure it is snug but not over-tightened.
Attach splash guard
If your model includes a splash guard, snap it onto the top of the disposal flange.
Test operation and clean up
Restore power and water, run the disposal to verify proper function, then tidy the work area.
Run power and water test
Turn on the breaker, switch on the disposal, and run cold water; listen for unusual noises or vibrations.
Clean up and dispose of old unit
Wipe down the sink area, store tools, and deliver the old disposal to a recycling center if applicable.