Repair first, or replace?
Before you buy a new disposal, find out what is wrong with the old one. A humming unit that will not spin is often jammed, and an Allen key in the bottom socket may free it. A leak at the top flange or the side hose can be sealed. A cracked housing or a rusted-through body cannot be repaired, so it needs a new unit.
| Symptom | Often repairable? | What to do |
|---|---|---|
| Hums but does not spin | Yes | Clear the jam with a hex key, press the reset button |
| Dead, no hum | Often | Check the reset button and the power supply |
| Drips from the flange at the sink | Sometimes | Reseat the flange with fresh plumber's putty |
| Leaks from the body or bottom | No | Replace the unit |
| Loud grinding and vibration | Depends | Look for a foreign object, then consider replacement |
If the unit is repairable, our garbage disposal repair service is often the cheaper path than a new install. If it is not, the rest of this guide applies.
Choosing a unit that fits your sink
Motor size
Motor power is listed in horsepower. A smaller motor handles scraps and soft food. A larger motor shreds tougher waste more quietly. Match the motor to how you cook, since a household that cooks from scratch every day puts more load on a disposal than a household that mostly eats out.
Feed type and mounting
Continuous-feed units run while the switch is on. Batch-feed units run only when a stopper is in place, which some households prefer for safety. Check that the new unit uses the same mounting system as your sink flange, because a mismatch means changing the flange as well.
Dishwasher connection
Most disposals have a small inlet where the dishwasher drain hose connects. On a new unit this inlet is capped with a plastic plug. If you have a dishwasher, you must knock that plug out before you hang the unit. People skip this step and then find the dishwasher backs up into the sink.
Installation steps in order
- Switch off the circuit breaker, then confirm the power is off with a tester.
- Disconnect the old unit from the drain, the dishwasher hose and the power, and lift it out.
- Remove the old mounting ring and flange from the sink opening, and clean the area.
- Press a rope of plumber's putty under the new flange and seat it in the drain opening.
- From below, fit the gasket, backup ring and mounting ring, then tighten the mounting screws evenly.
- Knock out the dishwasher plug if the dishwasher drains into the unit.
- Wire the unit, or connect the power cord, following the maker's instructions.
- Hang the unit on the mounting ring and lock it in place.
- Connect the discharge tube to the trap, and attach the dishwasher hose with its clamp.
- Restore power, run water and check every joint for drips.
Turn off the breaker, then test the wires
Never rely on a wall switch alone. A switch controls only part of the circuit. Flip the breaker, confirm there is no voltage, and keep the area dry while you work. If you are not comfortable with wiring, hire a licensed professional.
Checks that decide whether to DIY
Hire a plumber if any of these apply
- There is no power outlet under the sink and one needs to be added
- The drain trap does not line up with the new unit and needs reworking
- The sink flange is old, corroded or a different style from the new mount
- The kitchen drain has a history of slow flow or clogs
- You are adding a disposal where none existed before
A first-time install is often a plumbing installation job. It may involve a new drain arrangement, an outlet and a switch. The mechanical part is not hard, but the combination of water and electricity rewards a careful person.
Licensing and permit notes for Romeoville installs
The Illinois Department of Public Health licenses plumbers under the Illinois Plumbing License Law. The state says people who plan, install, alter or repair plumbing must be licensed. Check the state licensing information before you hire anyone.
Nearby towns publish their own rules. Plainfield lists the 2014 State of Illinois Plumbing Code, with the latest amendments and a village IDPH amendment, among its adopted codes. Bolingbrook says permits are required for repairs and alterations and asks for three business days' notice before an inspection.
The Village of Romeoville sets its own permit rules. Call its building department before a first-time install if wiring or drain changes are involved. Waiting for an inspection can delay the finish date, so ask early.
Stuck halfway through an install?
If the trap will not line up or the wiring looks wrong, stop and call. We can finish the job or fix what is already in place.
Call (630) 822-9290What to put down a disposal and what to skip
A disposal handles soft scraps and small bones poorly. Fibrous peels, coffee grounds in volume, grease and starchy foods such as rice and pasta are the usual causes of a clog below the unit. Run cold water before, during and for about fifteen seconds after use so the waste travels past the trap.
- Skip grease, oil and fat, which coat the pipe wall after cooling
- Skip fibrous items such as celery strings and corn husks
- Skip large amounts of rice, pasta and potato peels
- Use cold water while the unit runs
- Cut large scraps into smaller pieces
For homes in Bolingbrook and Plainfield as well as Romeoville, a kitchen drain may already be marginal. A new disposal sends more solids into that line, so a cleaning before the install can prevent a backup the first week.
Garbage disposal installation questions
A straight swap of the same type is a short job for a plumber. A first-time install with new wiring or drain work takes longer.
Yes, if the dishwasher drains into the disposal. The plug is a thin plastic knockout inside the inlet. Leave it in place and the dishwasher cannot drain.
Most fit a standard 3.5 inch sink opening, but mounting styles differ. Check that the new mount matches your existing flange or plan to replace the flange.
Yes. The emergency line runs around the clock. If a disposal is leaking under the sink, turn off the water supply to the kitchen and call.
Rules differ by town. Bolingbrook says permits are required for repairs and alterations, and Plainfield publishes its adopted plumbing code. For Romeoville, ask the Village building department before you start.
No. A disposal grinds waste but does not clear a clogged line. If the sink drains slowly now, have the line cleaned before or at the time of the install.