What the job really involves
Split the work into five small tasks. You remove the old strainer or disposal, seat a new sink flange, hang the disposal body from the mounting ring, connect the discharge tube to the trap, and finish the power connection. A screwdriver, channel locks, a hammer, plumber's putty, and a non-contact voltage tester cover almost everything.
Weight is the surprise. A 1/2 horsepower unit runs about 10 pounds, while a 1 horsepower model with sound insulation can pass 15. Ask a helper to hold the body while you lock it onto the ring, because a dropped disposal cracks its housing.
The install, in order
Read the manual that comes with your model first, since mounting hardware differs between brands.
Cut power and clear the cabinet
Switch off the breaker that feeds the sink outlet and confirm it is dead with the tester. Empty the cabinet and set a bucket under the trap.
Remove the old parts
Loosen the slip nuts on the trap and the discharge tube. If you are replacing a disposal, twist the lock ring free and lower the old body. If you are starting from a plain strainer, unscrew the strainer nut from below.
Seat the sink flange
Roll a rope of plumber's putty about 1/2 inch thick and press the new flange into the sink opening. From below, add the gasket, backup ring, and mounting ring, then snap the retaining ring on. Tighten the three screws evenly until putty squeezes out, and trim it.
Knock out the dishwasher plug
If a dishwasher drains into this unit, open the inlet now, while the body is easy to hold. The next section explains how.
Hang the disposal
Lift the body onto the mounting ring and turn the lock ring until it clicks or the tabs seat. Rotate the unit so the discharge port lines up with the trap arm.
Join the drain and the power
Bolt the discharge tube on with its flat gasket, then rebuild the trap with fresh washers. Make the electrical connection last, using the cord kit or the wire nut method described below.
Test for leaks
Plug the drain, fill the sink halfway, and release it while you run a dry paper towel around every joint. Then switch the disposal on with cold water running and feed it a few ice cubes.
Wait until the paper towel stays dry for a full minute of running water.
Power and cord
Most disposals ship without a cord. You buy a 3 prong cord kit and wire it to the unit's terminal box, or you hardwire the disposal into a switched cable. Both are legitimate. The deciding factor is what already exists in your cabinet.
With the power off and verified, open the plate on the bottom of the disposal. Match black to black, white to white, and green or bare copper to the green ground screw, then close the plate. A loose ground is a common wiring mistake, so tug each wire once.
Stuck on wiring or a leaking drain? Call (385) 488-1892 and a licensed plumber can take over.
Call (385) 488-1892Plug-in or hardwired
| Factor | Plug-in with cord kit | Hardwired |
|---|---|---|
| Outlet under the sink | Required, ideally switched or with a countertop switch | Not needed, but a switched cable must reach the unit |
| Future replacement | Unplug, swap, plug in | Disconnect wires at the terminal box again |
| Typical DIY level | Reasonable with a tester and care | Reasonable only if the cable and switch already exist |
| New wiring needed | Only if no outlet exists | Only if no switched cable exists |
| Best choice when | A grounded outlet is already in the cabinet | A previous disposal was hardwired and the box is intact |
If neither an outlet nor a switched cable exists, stop. New wiring is electrician work, and it has permit consequences in Herriman.
The dishwasher knockout plug
Many new disposals have a thin plastic plug blocking the small side inlet where a dishwasher hose connects. If a dishwasher drains into your sink, that plug has to come out. Set a flat screwdriver against it from inside the grind chamber and tap the handle with a hammer until it drops.
Fish the plug out by hand with the power off. Left behind, it can jam the cutter plate on first use. Skipping the step altogether is the usual reason a new install leaves a dishwasher full of gray water.
No dishwasher? Leave the plug in place. Then confirm your dishwasher hose rises into a high loop under the countertop or runs through an air gap, as its instructions describe.
Herriman rules and water that shape this job
The city's building page says repair and maintenance of existing plumbing and electrical systems needs no permit, but adding new electrical or plumbing lines to a home does. A like-for-like disposal swap is maintenance. A new outlet circuit or a new drain branch is not, so ask the Herriman Building Department before you cut into a wall.
Jordan Basin Improvement District runs the sewer system here and tells customers never to pour oil or grease down sinks, toilets, or disposals. It says to let grease cool and harden in a can, then throw it away. A disposal grinds food but does nothing to stop grease from coating the line, so keep that can beside the stove.
Herriman's own water quality page calls local water very hard, with city wells between 25 and 60 grains per gallon and Jordan Valley Water supply between 10 and 12. Expect crusty mineral buildup on old flanges and slip nuts. Buy a spare set of washers and give yourself extra time on a decade old sink.
Signs this should be a licensed plumber's job
Call a professional rather than pushing on when any of these show up.
- The cabinet has no outlet and no switched cable, so the job now includes new wiring.
- The old drain pipe is cast iron, galvanized, or corroded enough to crumble when touched.
- The sink flange area is cracked, or the sink is a thin stainless or composite model that will not seat a mounting ring.
- Water appears at the cabinet floor after the test and you cannot trace it.
- The trap arm does not line up with the wall stub and needs a re-pipe.
- You are not sure the breaker is off, or you smell hot wiring.
A licensed plumber can repair or replace a disposal in a single visit, and larger kitchen changes fall under plumbing installation work.
The same call applies for homeowners in Riverton and South Jordan, since dispatch is based in Herriman and covers both.
Garbage disposal install questions
Does swapping a garbage disposal in Herriman need a permit?
The city's building page says repair and maintenance of existing plumbing and electrical systems does not require a permit, while adding new electrical or plumbing lines does. A direct swap on existing drain and power is maintenance. If you are adding a circuit or a drain branch, ask the Herriman Building Department first.
How long does a garbage disposal last?
Most last roughly 8 to 15 years depending on use. Hard water scale on the grind components and heavy grease use shorten that.
Can a disposal share a circuit with a dishwasher?
Often yes, but check each appliance's amp rating against the breaker. Combined starting loads can trip a 15 amp breaker. An electrician can confirm what your panel supports.
My new disposal hums but does not spin. What now?
Turn the power off and insert the hex key that came in the box into the socket on the underside, then work it back and forth. Press the reset button on the base and try again.
Do I need an air gap for the dishwasher?
That depends on the dishwasher's instructions and local code. Some use a high loop under the countertop instead. Follow the manual and ask the building department if unsure.
Want a pro to finish the job? Call (385) 488-1892 and ask about the next open slot.
Call (385) 488-1892Sources and standards
Local rules and figures in this guide come from the public sources below. Fees and codes change, so confirm the current version before you act on it.