My garbage disposal made a noise like a cement mixer full of rocks, then stopped making any noise at all. The reset button did nothing. The Allen wrench trick did nothing. It was dead. And I had never touched plumbing in my life.

I called a plumber. Quote: $280 for labor alone — the disposal itself would be extra. I hung up and watched a YouTube video. Two hours later I had a new disposal installed and running. Here is exactly what I did.

Before You Touch Anything: Safety

Garbage disposals run on electricity. Water and electricity do not mix. Unplug the disposal from the outlet under the sink. If it is hardwired, turn off the breaker. Test that it is dead by flicking the switch before you reach under there.

Put a bucket under the P-trap. When you disconnect the plumbing, the water in the trap will come out. It smells. Have a towel ready.

Removal: Easier Than You Think

The disposal is held to the sink by a mounting ring with three tabs. It twists on and off — no screws, no bolts. The whole unit is suspended from that ring.

1. Disconnect the drain pipe from the disposal’s discharge tube. One screw clamp.
2. Disconnect the dishwasher hose if you have one. Another clamp.
3. Support the disposal from underneath — they are heavier than they look. Most are 10-15 pounds of solid metal.
4. Insert the special wrench that came with the new disposal (or a large flathead screwdriver) into one of the mounting ring loops and twist counterclockwise. The disposal drops free.

The hardest part was supporting the old disposal with one hand while twisting the mounting ring with the other. I balanced it on a stack of books. Not elegant, but it worked.

Installation: Match the Brand If You Can

If you buy the same brand as your old disposal — Insinkerator for Insinkerator, Waste King for Waste King — the new unit probably fits the old mounting ring. You just twist the new disposal onto the existing ring and reconnect the plumbing. Twenty minutes.

If you switch brands, you need to swap the mounting ring too. It is not hard, just a few extra steps — remove the old ring from the sink flange, install the new ring, apply plumber’s putty to the flange. The instructions in the box walk you through it.

The Dishwasher Connection Plug

New disposals come with a plastic knockout plug in the dishwasher inlet. If you have a dishwasher, you must knock this plug out with a screwdriver and hammer before installation. If you forget — and I forgot — the dishwasher will not drain and you will have to take the whole thing apart again. Ask me how I know.

Testing

Reconnect the drain and dishwasher hose. Plug it in. Run cold water. Flip the switch for one second and listen. If it sounds smooth — you are done. If it sounds like metal grinding — something is inside the grinding chamber. Unplug, reach in with pliers, remove the obstruction.

Check for leaks at all connections. A drip at the discharge tube or dishwasher inlet is usually just a clamp that needs another half-turn of tightening.