My garbage disposal started making a noise I can only describe as “angry rocks.” Then it stopped making any noise at all. Just a low hum when I flipped the switch, followed by silence. The reset button on the bottom did nothing. The Allen wrench trick — turning the flywheel manually from underneath — did nothing. It was dead.

I called a plumber for a quote: three hundred and fifty dollars including the new unit. I bought a new disposal for ninety dollars and installed it myself in about two hours. Most of that time was spent lying on my back under the sink, staring at pipes, questioning my life choices. The actual work was straightforward.

Before You Start: Unplug It

This is not a suggestion. Unplug the disposal from the outlet under the sink. If it is hardwired, turn off the breaker and tape it so nobody flips it back on. A disposal is a blender for sink waste and it will remove fingers. Respect the machine.

The Removal

1. Disconnect the drain pipe from the disposal — the horizontal pipe that runs to the main drain. Loosen the slip nut with pliers. Have a bucket under it because water will come out.
2. Disconnect the dishwasher hose if you have one. It is a rubber hose clamped to a small nipple on the side of the disposal. Squeeze the clamp with pliers and slide it off.
3. Support the disposal with one hand. Insert a screwdriver into the mounting ring tab and turn counterclockwise. The disposal will drop free. It is heavy — about fifteen pounds — so be ready for the weight.

The Installation

If your new disposal is the same brand as the old one, the mounting ring on the sink is probably compatible — you can skip to hanging the new unit. If not, you need to swap the mounting assembly. This involves removing three screws, a snap ring, and the old flange. Your new disposal comes with instructions and the new mounting hardware.

To hang the new disposal:

1. Line up the three mounting tabs on the disposal with the three ramps on the mounting ring.
2. Lift and turn clockwise until it locks. You will feel it seat.
3. Reconnect the dishwasher hose and drain pipe. Tighten the slip nuts hand-tight plus a quarter turn with pliers — do not overtighten or you will crack the plastic.
4. Plug it in. Turn the breaker back on.

The Knockout Plug

If you are connecting a dishwasher, there is one thing the instructions will mention: knock out the dishwasher inlet plug inside the disposal’s inlet nipple before connecting the hose. It is a plastic disc blocking the hole. Stick a screwdriver in and tap with a hammer — it pops right out. If you forget this step, your dishwasher will not drain and you will have a very wet kitchen floor.

I forgot this step. My dishwasher backed up and flooded the cabinet. I got to take the hose off, knock the plug out, and reconnect everything while standing in a puddle. Learn from my puddle.

Test for leaks by running water through the disposal for a full minute while feeling every connection with a dry paper towel. Any moisture at all — tighten that connection.

Ninety dollars and two hours versus three hundred and fifty. I have since installed two more for friends. The first one is the only hard one.