What You Need Before You Start

A Badger garbage disposal installs under your sink in place of the old one, or as a new unit if you don't have one yet. The job takes two to four hours and requires basic hand tools—a wrench, screwdriver, and adjustable pliers—plus a bucket to catch water. You'll also need plumber's putty and a new rubber gasket if you're replacing an old unit.

Before you begin, turn off the power at the breaker box to the outlet under your sink. If you're replacing an existing disposal, turn it on and run cold water to clear any debris, then turn it off and unplug it. If you're installing in a new sink opening, you'll need a hole saw to cut a 3.5-inch hole in the sink basin—most modern sinks come pre-drilled for this.

Check your sink's plumbing setup. You need a P-trap (the curved pipe under the sink) and a drain line running to the wall. If your sink has a dishwasher, you'll need a dishwasher inlet on the disposal. Badger makes models with and without this feature, so confirm which one fits your setup before you buy.

Key Takeaways

  • Turn off power at the breaker box before you touch any wiring or the old disposal.
  • The mounting ring screws to the sink flange from underneath, and the disposal hangs from that ring—do not skip tightening the mounting bolts or the unit will leak.
  • The discharge tube connects to your P-trap with a slip nut; hand-tighten first, then use a wrench to snug it without crushing the rubber seal.
  • Once installed, run cold water for 30 seconds before and after grinding to protect the motor and clear the drain.
  • If water leaks from under the sink after installation, the mounting bolts are loose—tighten them in a cross pattern like a car wheel.

Remove the Old Disposal (If You Have One)

Place a bucket under the P-trap to catch standing water. Loosen the slip nut that connects the discharge tube (the pipe coming out of the disposal) to the P-trap using an adjustable wrench. Turn it counterclockwise by hand first, then use the wrench to break it loose. Slide the discharge tube out of the P-trap.

If your disposal is hardwired (connected directly to the electrical box rather than plugged in), you must call a licensed electrician to disconnect it. Do not cut the wire yourself. If it's plugged into an outlet, unplug it now.

Locate the three mounting bolts on the mounting ring that holds the disposal to the sink. These are under the sink, spaced around the ring. Loosen all three bolts by turning them counterclockwise with a wrench. The disposal will drop into your hands—it's heavy, so support it as you work. Set it aside or have someone help you lower it into the bucket.

Prepare the Sink Flange for the New Unit

The sink flange is the metal ring that sits in the drain hole at the top of the sink. Scrape away all old plumber's putty from the underside of the sink around the flange using a putty knife or old credit card. Wipe the area clean with a damp cloth and let it dry completely.

Roll a rope of fresh plumber's putty about the thickness of a pencil and press it around the underside of the sink flange, making a complete circle. This creates a watertight seal between the sink and the mounting ring. Don't skimp on the putty—gaps here are the most common source of leaks.

If you're installing in a new sink hole, insert the flange from the top of the sink so the wider collar sits on top of the basin. The threaded part should point downward into the cabinet.

Install the Mounting Ring and Gasket

Slide the rubber gasket (a flat ring that came with your Badger unit) onto the threaded part of the flange from underneath the sink. This gasket compresses when you tighten the mounting bolts and creates the seal that stops leaks.

Slide the mounting ring onto the threaded flange. This ring has three evenly spaced bolt holes. Insert the three mounting bolts through the holes and thread them by hand into the flange. Do not tighten them all the way yet.

Tighten the bolts in a cross pattern—if they were at 12 o'clock, 4 o'clock, and 8 o'clock, tighten 12, then 4, then 8, then repeat. Turn each bolt a quarter turn at a time. This distributes pressure evenly and prevents the gasket from pinching unevenly. Stop when the ring is snug against the sink and the gasket is compressed. You should not be able to move the ring by hand, but do not over-tighten—you'll crack the gasket.

Hang the Disposal and Connect the Discharge Tube

The Badger disposal has a mounting collar on top that hooks onto the mounting ring. Align the three tabs on the collar with the three slots on the ring. Lift the disposal up and slide the collar onto the ring, then twist it clockwise about a quarter turn until it locks. The disposal should hang securely and not move when you push it gently.

The discharge tube is the pipe that sticks out from the side of the disposal. Slide it into the P-trap opening. The slip nut (a large nut with a rubber washer inside) screws onto the discharge tube and tightens against the P-trap. Hand-tighten the slip nut first, then use an adjustable wrench to snug it another half turn. Do not over-tighten—you'll crush the rubber washer and create a leak that gets worse over time.

If your old discharge tube is damaged or doesn't fit, Badger sells replacement tubes in different lengths. Measure from the disposal outlet to the P-trap opening before you buy.

Connect the Dishwasher Inlet (If Applicable)

If you have a dishwasher and your Badger model has a dishwasher inlet, locate the inlet port on the side of the disposal. It's a small threaded opening, usually with a rubber cap. Remove the cap and screw the dishwasher hose connector onto the inlet using a wrench. Tighten it snugly but not hard enough to crack the plastic.

Run the dishwasher drain hose from your dishwasher to this inlet. The hose should slope downward slightly to prevent water from backing up into the dishwasher. Clamp the hose to the inlet with a hose clamp, tightening it with a screwdriver until it's snug.

If you don't have a dishwasher or your model doesn't have an inlet, leave the cap on. Some Badger models come with a removable plug instead of a cap—do not lose it, as it seals the opening.

Restore Power and Test

If the disposal is plugged into an outlet, plug it back in now. If it's hardwired, the electrician will restore power when they reconnect it. Turn the breaker back on at the electrical panel.

Run cold water from the tap for 30 seconds to flush the drain and check for leaks. Look under the sink with a flashlight. Water should not drip from the slip nut, the mounting bolts, or the flange. If you see drips, turn off the water and tighten the leaking connection a quarter turn at a time until it stops.

Turn on the disposal and let it run for a few seconds with the water running. It should make a normal grinding sound. If it makes a loud rattling or grinding noise that sounds wrong, turn it off when ready and check that nothing is stuck inside. Never put your hand into the disposal—use tongs or pliers to fish out debris.

Frequently Asked Questions

Can I install a Badger disposal myself or do I need a plumber?

If you're comfortable with basic hand tools and the disposal is plugged into an outlet, you can do it yourself. If the old disposal is hardwired to the electrical box, you must hire a licensed electrician to disconnect and reconnect the wiring—this is a safety and code requirement.

What if water leaks from under the sink after I install it?

Leaks almost always come from loose mounting bolts or a slip nut that isn't tight enough. Turn off the water, place a bucket under the leak, and tighten the bolts or slip nut a quarter turn. Repeat until the leak stops. If the leak is at the flange (where the disposal meets the sink), you may need to remove the disposal and add more plumber's putty.

How do I know which Badger model to buy?

Badger makes models in different horsepower sizes (typically 1/3, 1/2, and 3/4 horsepower) and with or without a dishwasher inlet. For a typical household, 1/2 horsepower is standard. Check whether your sink has a dishwasher connection before you buy—if it does, get a model with an inlet.

Do I need to use plumber's putty or can I use caulk?

Use plumber's putty, not silicone caulk. Putty stays pliable and can be removed later if you need to service the disposal. Caulk hardens and makes future removal difficult. Plumber's putty is inexpensive and available at any hardware store.

Can I run the disposal without water?

No. Always run cold water for 30 seconds before you turn on the disposal and keep the water running while it grinds. The water cools the motor and flushes ground food down the drain. Running it dry can damage the motor and cause clogs.