How To Plumb A Garbage Disposal?
A proper plumbing connection to the garbage disposal unit is a prerequisite for successful installation.
If you fail to plumb the garbage disposal unit properly, you will experience problems, such as leaks, clogs, or worse.
To avoid those issues, you should plumb the food waste disposer correctly.
That’s where this guide comes into play. This how-to guide will walk you through step-by-step instructions to plumb the garbage disposal unit.
As a result, you can confidently connect the plumbing, such as attaching the drain line to the disposal’s discharge tube, connecting the dishwasher tube to the disposal’s inlet, and installing the p-trap between the disposal and the drain line.
Without further ado, let’s dive deeper.
Table of Contents
- Tools & Materials Needed:
- How To Plumb A Garbage Disposal Unit: Step-By-Step Instructions?
- FAQs
- Conclusion
Note: This guide only walks you through a step-by-step process to connect the disposal to the plumbing. To connect the disposal unit to a power source, you can read this article on garbage disposal installation. Or, you can check out this guide that explains how to wire a garbage disposal with a plug-in cord.
Tools & Materials Needed:
Before plumbing your garbage disposal, gather these tools and materials at your fingertips:
- Plumber’s putty
- Wrenches
- Teflon tape (for sealing pipe threads)
- PVC pipes and fittings (for drain connections)
- P-trap (for connecting the disposal unit to the drain line)
- Discharge tube (connects to the garbage disposal unit)
How To Plumb A Garbage Disposal Unit: Step-By-Step Instructions?
To plumb your garbage disposal correctly, go along with these steps:
Prepare The Sink Flange
The sink flange is a metal component that connects the food waste disposer to the sink.
You must first apply the plumber’s putty underside to the sink flange to create a watertight seal between the sink and the flange.
Regarding this, make a small ball with the plumber’s putty and turn it into a rope. Then, apply the plumber’s putty around the underside of the sink flange.
Then, press the sink flange into the sink opening and put a weight on it.
Attach the Mounting Assembly To The Sink Flange
Go under the sink flange.
Slide the fiber gasket through the sink flange. Next, insert the backup flange, mounting ring, and snap ring into the sink flange.
Then, secure the mounting assembly by tightening the three nuts. Afterward, go to the top of the sink opening and scrape the excess plumber’s putty using a putty knife.
Connect The Garbage Disposal To The Mounting Assembly
After attaching the mounting assembly to the sink flange, it’s time to connect the disposal unit to the mounting assembly.
Lift your garbage disposal and align it with the mounting assembly under the sink.
Next, turn the disposal unit clockwise until it locks in place. Ensure the garbage disposal unit is secured tightly to avoid wobbling or loose connections.
Attach The Discharge Tube To The Disposal Unit
Connect the discharge tube to the garbage disposal.
Sit the discharge tube’s gasket on the discharge tube.
Then, insert the elbow flange into the discharge tube, align the discharge tube with the disposal’s discharge outlet, and secure the connection with the nuts.
Install the Trap and The Drain Pipes
Now, install the trap and the horizontal drain pipes.
Connect the trap to the discharge tube and secure it with the pipe connector. Then, attach the drain pipes to the P-trap. Ensure the pipe connections are snugly secured with slip nuts and washers.
The scenario can be different if you install a garbage disposal under a double sink. In this case, you should install a straight pipe.
Connect the Dishwasher Line To The Disposal
Skip this step if you don’t have a dishwasher line.
To connect the dishwasher hose, slide the dishwasher hose into the disposal’s inlet and secure the connection with the clamp nuts.
Don’t forget to remove the knock-out plug from the disposal inlet before connecting the dishwasher line to the disposal unit.
Hammer down the knock-out plug and remove it from the grinding chamber.
Check For Leaks
Once you complete the plumbing connection, it’s time to check for leaks.
Turn on the cold water faucet and let the water flow for a few minutes. Check all the plumbing connections under the sink.
If the leak appears, tighten the connections.
FAQs
Should I shut off the water supply before plumbing a garbage disposal unit?
You don’t need to shut off the cold water supply before plumbing a garbage disposal unit. Just ensure the under-sink area is dry to avoid leaks while working.
Do I need to use the plumber's putty when installing a garbage disposal?
You must apply the plumber’s putty to create a watertight seal between the sink flange and the drain opening. The plumber’s putty creates a watertight seal to prevent water leaks.
What are common mistakes to avoid when plumbing a garbage disposal?
Common mistakes you should avoid when plumbing a garbage disposal unit are:
- Failing to check for leaks
- Not applying the plumber’s putty
- Improper pipes alignment
Conclusion
Correct plumbing is essential for a successful garbage disposal installation.
Following our step-by-step instructions, you can properly attach the plumbing to the disposal unit.
Whether you are an experienced DIYer or a novice, you can confidently connect the garbage disposal to the plumbing under the sink.
Keep in mind; that this how-to guide only shows the way you can connect the disposal unit to the plumbing. It doesn’t include an important garbage disposal installation process- wiring the garbage disposal.
Without wiring the garbage disposal unit, you can’t power the food waste disposer to grind food particles.
To get detailed guidelines from wiring to plumbing to troubleshooting, you can check out the comprehensive garbage disposal manual.
Our garbage disposal manual covers everything to make your installation a success.
Sohel Rana is the founder of FixTheDisposal.Com. He is a plumbing expert with 7+ years of hands-on repairing garbage disposals, water heaters, space heaters, and other appliances used in a home. Before the launch of Fix The Disposal, he wrote and provided advice on water heaters, sump pumps, and space heater repairing & troubleshooting tips for LilDutchUncle.Com.
