Garbage Disposal Installation and Troubleshooting Guide

A garbage disposal makes kitchen cleanup faster and reduces food waste going to landfills. When one jams, leaks, or stops working, it brings the whole kitchen to a halt. This guide covers installing a new unit, fixing the most common problems, and keeping your disposal running for years.

Choosing a Garbage Disposal

Key specs to consider before buying:

Motor size: Measured in horsepower (HP). For most households, ½ HP handles light use; ¾ HP works for average families; 1 HP is best for heavy daily use or tougher food waste
Grinding stages: Two-stage grinders (with stainless impellers and a grind ring) are more effective and less prone to jamming than single-stage units
Sound insulation: Higher-end models include foam or anti-vibration mounts that significantly reduce noise
Capacity: Larger grind chambers reduce jam frequency

The InSinkErator Evolution Compact is a ¾ HP two-stage unit with excellent jam resistance and sound insulation — a great mid-range choice. For heavy use, step up to the InSinkErator Evolution Excel 1 HP.

Tools and Materials Needed

Adjustable pliers or channel-lock pliers
Screwdrivers (Phillips and flathead)
Plumber’s putty
Bucket and towels
Flashlight

Most disposals include all mounting hardware and electrical connections needed for installation.

How to Install a Garbage Disposal

Step 1: Disconnect Power

Turn off the circuit breaker for the disposal. If the unit is hardwired, verify power is off with a voltage tester. If it plugs in, unplug it.

Step 2: Remove the Old Disposal

Disconnect the discharge tube (the pipe going from the disposal to the drain)
If connected to a dishwasher, remove the drain hose from the disposal inlet
Insert a flathead screwdriver or the disposal wrench into the mounting ring and turn counterclockwise to release the unit from the mounting assembly
Lower the old disposal and set it aside

Step 3: Install the Sink Flange

If replacing the mounting assembly (most replacements will use the existing one):

Remove the old flange from below the sink — unsnap the snap ring, remove the backup ring, fiber gasket, and upper mounting ring
Roll plumber’s putty into a rope and press it around the underside edge of the new sink flange
Push the flange into the drain hole from above
From under the sink, install the fiber gasket, backup ring, and upper mounting ring
Tighten the mounting ring screws evenly until the putty squeezes out above
Scrape away excess putty from above

Step 4: Wire the Disposal

If your disposal is hardwired:

Remove the wiring cover plate from the bottom of the unit
Connect white to white, black to black, green to ground using wire nuts
Replace the cover plate

If it plugs in, ensure the outlet is a GFCI-protected outlet.

Step 5: Mount the Disposal

Lift the disposal and align its mounting tabs with the mounting assembly
Turn clockwise until it locks into place
Connect the discharge tube to the drain outlet (with the provided gasket)
Connect the dishwasher drain hose if applicable (knock out the plug inside the inlet with a screwdriver first)

Step 6: Test

Turn the water on first, then restore power and run the disposal briefly. Check all connections for leaks.

Troubleshooting Common Problems

Disposal Won’t Turn On

Check the reset button: A small red or black button on the bottom of the unit. Press it firmly — you may feel or hear a click
Check the circuit breaker: Reset if tripped
Test the outlet: Plug something else into the outlet to confirm it has power

Disposal Is Humming but Not Spinning (Jam)

A jam means something is stuck between the impellers and the grind ring.

Turn off the power — do not put your hand inside while power is on
Use the disposal wrench (often included, or use a garbage disposal Allen wrench) in the hex socket on the bottom of the unit and work it back and forth to free the jam
Use tongs to remove the object from inside the chamber
Press the reset button, restore power, run with water

Disposal Is Leaking

Leaking from the sink flange (top): Putty has dried or the mounting bolts have loosened — tighten the mounting ring screws or reseat with fresh putty
Leaking from the discharge outlet: Tighten the screws or replace the discharge outlet gasket
Leaking from the bottom (bottom of the unit): Internal seal failure — the unit needs replacement, as internal seals are not serviceable

Disposal Smells Bad

Run the disposal with cold water and a cut lemon or orange. For deep cleaning, put a cup of ice and a half cup of salt down the drain and run the disposal — the ice and salt scrub the grinding components.

What Not to Put in a Garbage Disposal

Grease, oil, or fat — they solidify and coat the chamber
Fibrous vegetables (celery, asparagus, artichokes) — fibers wrap around the impellers
Starchy foods (potato peels, pasta, rice) — expand and create thick paste
Bones larger than small chicken bones
Coffee grounds — accumulate and clog the drain
Non-food items of any kind

Conclusion

Garbage disposal installation is one of the more manageable DIY plumbing projects, typically completed in under two hours. When problems arise, work through the reset button and jam-clearing procedure before assuming the unit needs replacement. With proper use — no grease, no fibrous vegetables, always running cold water — a quality disposal lasts 10–12 years.