Can you install a disposal yourself? Usually, with two conditions
Yes, if you are replacing a disposal that is already there and you have a switched outlet under the sink. A like-for-like swap uses the same drain opening, the same sink flange, and the same power. Plan on an afternoon and a helper to hold the unit while you lock it in place.
Hand it off if the sink has never had a disposal, if there is no outlet or switch, or if the drain below is slow. The first case needs a drain connection and often an electrical change. The second and third are the situations where a careful DIY job still ends in a leak or a clog.
What decides how hard your install will be
| Your setup | Why it matters | Plan |
|---|---|---|
| Replacing an old disposal | Same mounting ring and drain opening often carry over | DIY is realistic. |
| First-time install, no disposal ever | The sink needs a disposal flange and a new drain connection | Licensed plumber. |
| Dishwasher drains into the disposal | The dishwasher hose connects to a side inlet, and a knockout plug must be removed | DIY with care. |
| Outlet under the sink, wall switch above | Power is already handled | DIY. |
| No outlet, or a switch that does nothing | New wiring is an electrician's job | Licensed electrician first. |
| Slow drain before you start | A new disposal pushes more food into a line that is already restricted | Clear the line first. |
Not sure your sink can take a disposal?
Call (855) 575-2890 and describe the sink, the drain, and the power under it.
The installation in eight steps
- Cut the power
Unplug the old unit, or turn off its breaker and test with a non-contact tester. Do not trust the wall switch alone.
- Disconnect the old unit
Loosen the drain tube and the dishwasher hose. Hold the disposal while you twist the mounting ring free, since it is heavy.
- Clean the sink opening
Scrape off old putty. Check the flange for cracks or a warped lip, and replace it if it is damaged.
- Seat the new flange
Press a rope of plumber's putty under the flange and tighten the mounting ring until putty squeezes out evenly. Wipe the excess.
- Knock out the dishwasher plug
If a dishwasher will connect, tap out the plug inside the side inlet and fish it out. Skipping this blocks the dishwasher drain.
- Hang the disposal
Lift it onto the mounting ring and rotate until it locks. Align the discharge outlet with the trap arm.
- Connect drain and hose
Fit the discharge tube with its gasket, then clamp the dishwasher hose to the side inlet.
- Restore power and test
Plug in, turn on the water, run the unit a few seconds, and check every joint with a dry paper towel.
Mistakes that cause leaks, jams, and hum
- The dishwasher plug stays in place, so dishwasher water has nowhere to go and backs up.
- One side of the mounting ring gets overtightened, which tilts the unit and weeps at the flange.
- A flattened old discharge gasket is reused. New units ship with one, so use it.
- The unit runs before the joints are checked, so a drip soaks the cabinet for an hour.
- Cold water is left off during use. A steady flow of cold water carries scraps through the trap and keeps grease from setting.
- The plumber's putty is skipped or smeared thin, and the sink flange seeps into the cabinet below.
Power and wiring: where DIY stops
A disposal draws real current, so treat the wiring with respect. Switch off the breaker, confirm the circuit is dead, and keep the cord clear of the damp cabinet floor.
If your unit is hardwired rather than plugged in, or if you have to add an outlet, bring in a licensed electrician. A plumber handles the water side and the drain. Permit rules for electrical and plumbing changes vary, so ask the building office before you start.
Continuous feed or batch feed, and how big
Continuous feed
Runs while the wall switch is on. It is the common type and the easier one to live with day to day.
Batch feed
Runs only when a lid is twisted into place. It costs more to buy, and it suits homes with small children.
Motor size
A bigger motor grinds faster and jams less, though it needs more room under the sink. Measure the cabinet before you shop.
Whatever you choose, a disposal does not make a drain bulletproof. Grease, fibrous peels, and coffee grounds still build up in the trap and the line beyond it. A drain cleaning visit is the fix when the sink backs up even with the unit running.
What a licensed plumber adds to the job
A plumber installs the unit and checks everything it touches. That means the drain tube slope, the trap, the vent that lets the sink drain, and the shutoff valves you will need next time.
If you would rather not wrestle a heavy unit overhead, our garbage disposal service covers installs and replacements, and you hear the clear price before work starts. Crews also reach Tremonton, about 20 miles north, and Perry, about 4 miles south.
Brigham City note: permits, licenses, and older downtown drain lines
The Brigham City building office handles permits and inspections through Community and Economic Development at (435) 734-6604. The city page does not spell out a rule for disposal swaps, so ask before you start. A short call can save you from redoing work if an inspection applies.
Older homes near downtown Main Street may still have older drain lines under the kitchen. A camera inspection confirms what yours has. If the line is rough or slow, clear it before a new disposal sends more waste into it. To check a plumber, use the Utah Division of Professional Licensing Verify a License tool, which lists apprentice, journeyman, and master classes.
Source type: City building office page and the Utah Division of Professional Licensing license lookup
Frequently Asked Questions
A swap with matching mounts often fits in an afternoon for a careful first-timer. A new install takes longer because the drain and wiring need work. Rushing the putty and the mounting ring is how leaks start.
Yes, if a dishwasher will drain through the disposal. The knockout plug sits inside the side inlet. Tap it out and take it out of the chamber, or dishwasher water has no path out.
A hum means the motor is getting power but the blades are stuck. Turn off the power, look for a jam from the top, and use the hex socket on the underside to turn the blades by hand. If it still hums, stop and call.
Permit rules vary, so ask the Brigham City building office at (435) 734-6604 before you start. The office is part of Community and Economic Development at 20 N. Main, 2nd Floor. A licensed plumber can tell you what they pull on a job like yours.
Not always. The sink needs the right opening size and a drain that flows freely. A slow or older line should be cleared or inspected first.
Sources and standards
- Plumbing codes in the UPC and IPC families set the rules for fixtures, venting and drains. Ask the Brigham City building office at (435) 734-6604 which edition and permit rules apply to your job.
- The Utah Division of Professional Licensing offers a public Verify a License tool for checking any plumber's license class.
Written by Brigham City Pro Plumbing. Last updated October 29, 2026.