Full Guide for How to Install or Replace a Garbage Disposal
0 8 min 2 mths

Using a garbage disposal unit simplifies the process of getting rid of food waste. The typical garbage disposal will last for a little over a decade. Do you know how to install a garbage disposal? Keep reading to learn about how to install a new unit either to replace an old one or to put one in place for the first time. 

What You Need to Know Prior to Starting Garbage Disposal Installation or Replacement

When you turn on the switch to activate your garbage disposal and you hear a hum or the sound of grinding metal, you’ll realize something is not right. If this happens, you’ll probably need to replace your garbage disposal. The good news is that it’s not a difficult process even if some plumbing work is required. We asked several licensed plumbers like Cheap Plumbers to share some tips about how to install a garbage disposal. What you’ll see below are their recommendations for a smooth, problem-free installation.

  • Check with local codes prior to putting in a garbage disposal. Some regions have plumbing codes that don’t permit disposals due to sewer capacity limits. They may also mandate the installation of an air gap if the disposal will be used along with a dishwasher. 
  • The disposal will connect to the sink and will need a discharge that connects to the drainpipe. The outlet hose for your dishwasher connects to the disposal.
  • Garbage disposals are usually available in different horsepower amounts. If your property has a septic system, you’ll require septic-safe disposal.
  • If you’re installing a garbage disposal for the first time, you’ll need to do some wiring and plumbing work. Will you be able to do this? If not, consider hiring a professional with the right skills. Most current building codes mandate a dedicated 20-amp 120-volt outlet beneath the sink close to the garbage disposal. The outlet must be controlled by a switch that is easy to access by anyone standing at the sink. You likely already have this switch in your kitchen. If you don’t, you need it if you’re installing a garbage disposal. 

Checking to See if You Should Replace Your Garbage Disposal

Disposal that isn’t working right might be fixable. Try these three things to see if you can fix it:

  • Check to see if there’s a jam. 

Is there something jamming your garbage disposal? If something like a piece of glass or some other hard object is trapped inside, the motor might have jammed. Switch off the power, turn off the water, and unplug the unit. If your garbage disposal is hardwired, you’ll need to turn off the breaker. Take out the rubber baffle located within the drain, use a flashlight to look into the hole, and use pliers or tongs to remove whatever is jamming the unit.

  • Manually turn the motor. 

For this step, you’ll need a hex wrench. Rotate the wrench back and forth until the motor turns a full revolution. Remove the wrench and turn on the motor.

  • Press the reset button. 

If your motor overheated following the prolonged operation, wait five minutes so that it cools down. Press the reset button. If there’s a jam, the motor might overheat.

Steps to Remove an Old Garbage Disposal

If the above mentioned steps didn’t resolve the problem, you’ll need to replace your garbage disposal. Here’s what you need to do:

Step 1. Switch Off the Power

Switch off the power to your disposal.

Step 2. Disconnect Drain Tap

Get a bucket of water and some towels before tackling this part. Unscrew the drain trap and disconnect it from your old disposal unit. Loosen the nut on the PVC pipe. Use the bucket to collect any water or debris that may be in the pipe. Remember to keep the pipe since it’ll be needed when putting in your near garbage disposal.

Step 3. Take Out Old Disposal

Insert the wrench one a lug on the mounting ring. Use your other hand to support the base of the garbage disposal. Doing so will ensure that the mounting ring doesn’t fall down when you loosen it. Turn in a leftward direction to unscrew it from the ring. 

Step 4. Unscrew Electric

Your next task is to disconnect your garbage disposal from the electrical supply. Use a screwdriver to take off the cover plate on the bottom of the unit and then disconnect the wires. 

Steps to Install a New Garbage Disposal

Step 1: Disconnect the Pipes and Take Out the Strainer

Start by disconnecting the circuit breaker linked to your kitchen. You will then need to place a bucket beneath the P-trap. Then detach the drainpipes, take out the sink strainer, and remove any excess putty.

Step 2: Apply Plumbers Putty

Apply plumbers putty to the flange and press it into place. Place a towel in the sink and put the disposal on the flange so that it doesn’t move.

Step 3: Install Snap Ring

Beneath the sink, put in place the fiber gasket, the backup flange, and the mounting ring. Then slide them onto the flange’s underside. Put on the snap ring. You can do this by pulling it open and snapping it into place. Then tighten the screws with a screwdriver. The snap ring should be firm against the backup flange. Finish this third step by wiping away excess putty.

Step 4: Attach to the Dishwasher Drain

You’ll need to connect to the dishwasher drain. A hammer can be used to tap out the drain plug. Remove it from the disposal’s inlet.

Step 5: Take Out and Reattach the Wire Cover Plate

Remove the wire cover plate and attach the electrical cord. Ensure that you match up the wire colors. Push the wires back in and then put the plate back on.

Step 6: Connect the Drain

Connect the drain by putting the gasket in the discharge outlet. After that, attach the discharge tube using the flange and bolts. Hang the disposal. You’ll do this by aligning the three tabs with the mounting ring. Use a wrench to turn and secure the tabs over the ridges. Attach the dishwasher drain. Ensure the discharge pipe is properly lined up and attach the drainpipes. Use a tee pipe before the P-trap.

Step 7. Test the Garbage Disposal

Test your connections. You can do this by, firstly, putting the stopper into the sink drain and, secondly, turning on the water to fill the sink. Check to see if there are any leaks. Plug in the garbage disposal and switch on the power.

If you’ve read all the steps and think that it’s a tall order for you, remember that you don’t have to do it yourself. You can call a licensed plumber to take out your old unit and install a new one. A licensed plumber knows the ins and outs of working with plumbing and electricity. They also understand how to install a garbage disposal. For the help you need, contact local plumbers to have a licensed professional do the work for you.