How to Install a Garbage Disposal

Last Updated:  November 2, 2020

Most homeowners use garbage disposals to dispose of kitchen refuse. Garbage disposal grinds the food particles to a near liquid state to allow it to flow through the drainage pipes without clogging them. Like any other machine, disposals stop working due to defects caused by grinding the wrong items, old age, or due to other reasons. After it dies, your disposal unit will require replacing. We can help you replace the unit by guiding you on how to install a new unit to your sink.

Common Instructions for all Disposals

garbage disposal parts

Do you want to install or replace your old faulty garbage disposal? If you do, you need to know that replacing or installing a new disposal unit isn’t a hard nut to crack as long as you are equipped with the necessary tools and materials.

Tools Required

Materials Required

Installation Process

Step 1: Examine your Sink

Check your sink to determine its size and the voltage of your old unit, the manner it’s connected, the space available for the new unit you intend to install, and its horsepower. It is also advisable to ask yourself whether you want a more powerful disposal unit as compared to the previous one or not. 1/2HP is ideal for light use, 3/4HP for normal use, and 1HP for heavy-duty grinding. Those are some of the things that you need to check out when buying a new disposal unit.

Step 2: Detach the Drain arm and dishwasher pipe from the old disposal unit

The drain arm is a plastic pipe that drains the waste from the disposal while the dishwasher tube drains from the dishwasher unit and is typically thinner. Before disconnecting the pipes, place a bucket under the tubes to hold the water that might spill when detaching the pipes.

Step 3: Remove the Old Disposal Unit

Here, you will find out that the old unit is now attached to the sink and the electric mains. While holding your unit with one hand, twist the unit until it detaches from the mounting then proceed to disconnect the electrical wiring. When disconnecting your unit from the mounting, it is advisable that you loosen the screws rather than pulling them out. Remove the retaining ring with a screwdriver before pushing the drain through the sinkhole. Complete the process by removing the old seal using an Exacto knife.

Step 4: Preparing to Install New Unit

How do you prepare for the new unit? Simply wipe the areas under the sink with clean water. Carefully read and understand the disposal’s installation instructions on its manual guide. It is also important to arrange all the parts accordingly to make the installation process easy. You don’t want to frantically look for screws or parts while installing the unit.

Step 5: Connect the New Disposal’s Hardware

tart by laying the plumber’s putty about a ¼-inch wide and 1 ft long around the sink drain perimeter. Place the new drain on the putty before putting a rag on the drain. Proceed to set your disposal unit on the rag while holding the drain into place as you attach the new mounting assembly. Let the mounting assembly connect just like the old one. Fix the washer and the backup ring onto the drain before fitting the retaining ring into place. Once you are satisfied that it is attached well, tighten the bolts or screws to hold the entire unit securely into place. Remove the excess putty that is around the drain.

et the electrical plate and check out the wiring before connecting it by matching the wires with their respective colors. White wires, for instance, should attach to other white wires before securing them with wire covers. Finish the electrical connection by connecting the black wire to the green screw located on the disposal unit and then returning the electrical plate.

Step 6: Installing the Garbage Disposal Unit

If you are planning to connect the unit to your dishwasher, unblock the dishwasher tubes by knocking the blocker out with a hammer and screw. Install your new unit by holding it securely to the mounting assembly then screw it in a clockwise direction until it holds securely. It is advisable to keep the assembly in place with the help of a screwdriver as you turn the unit. After you are through, make sure to apply clamps to secure the connection.

Step 7: Test

Ensure to test whether the connections are perfect by running water through the drains to ensure there are no leaks under the sink.

Installing to Double Sink

If you own a double sink in your kitchen, you will definitely want to have all of them fitted with a garbage disposal unit. However, you can’t buy two disposal units for the two sinks. This is because this will be too expensive not only to acquire the units but also to operate it. With one unit installed perfectly for both sinks, however, you won’t see the need for buying another unit. To install a disposal to a double sink, you need to follow the process below and have the necessary materials and tools.

Step 1: Remove the Broken Disposal Unit

This applies to people with an old faulty unit that they want to replace with a new unit installed to a double sink. If you don’t have any unit, just move to the preparation stage. Carefully disconnect the old unit starting with the disconnection of the electrical parts. Proceed to detach the drains connected to the disposal and then detach the unit from the flange.

Before proceeding, you will need to disconnect the disposal flange mounting from the sink drains. You, however, can still mount it on this flange if you are installing a disposal unit from the same brand. Some experts are likely to advise to replace it all the same for a better sealing of the drain.

Disconnect the discharge tube and the entire drainage system from the second sink. You can do this if the tailpiece, the tee, and the drainage tube are faulty. If it does not experience any leaks, however, there is no need to replace it.

Step 2: Install the New Disposal Unit

The preparation process of installing a disposal unit to a double sink is slightly different if you have to prepare the second sink differently. When working with a sink that will hold the disposal unit, you can follow the process we mentioned above. Having said that, let’s see how you need to prepare the second sink.

Installing the materials of the second sink isn’t a difficult task if you follow the correct procedure. Seal the sink flange with silicon because you can rely on it to seal off leaks since it sticks securely in place. While holding the tailpiece into place, turn it in a clockwise direction until it fits securely under the sink. Follow this with a tee and connect it to the tailpiece. The tee will allow you to attach the discharge tube to the disposal unit in the first sink.

Prepare the discharge tube by first connecting it to the already mounted disposal unit. Mark it right at the correct measurement and cut it with a hacksaw for a perfect disposal installation. You can then loosen the discharge tube from the disposal unit so that you can insert it to the tee before reconnecting again.

Step 3: Connect the Electrical

Once you are sure that you have mounted the garbage disposal on the first sink securely and the second sink is well fixed, now is time to connect the electrical wires. Removing the wire cover plate, get the wires to match according to their respective colors. Afterward, insert the wires back and then reattach the cover place for safety.

Step 4: Connect the Drains

Attach the discharge tube with the flange and the screws or bolts. Using a hammer and screwdriver, unblock the dishwasher drain before connecting it.

Step 5: Test Your Disposal Unit

Testing allows you to confirm whether your installed unit works. Simply fill both sinks with water and run it to check for leaks. You can then switch on the unit by plugging in the power cord.

Installing to a Single Sink

Installing a disposal unit to a single sink is even simpler as compared to installing the unit to a double sink. This is because you won’t connect in the second sink. Here are the simple steps to follow whether you are replacing an old fault disposal or installing a new one.

Step 1: Turn off the Electrical

Unplugging the power cord will ensure your safety by protecting you from electrical shocks. Before you disconnect the drains, put a bucket under the sink in order to trap water that might still be within the drains. Detach the drains as well as the strainer.

Step 2: Prepare the New Disposal

Apply a plumber’s putty or silicone around the perimeter of the flange and then push it into place to fit securely. Place a towel or rag in the sink while setting the disposal unit on the flange so that it doesn’t move.

Assemble the fiber gasket, the backup flange, and the mounting ring in that order and then slip them onto the flange. Pull the snap ring to open it in order to fix it into place easily. Thereafter, tighten the screws in an even manner for a secure fitting on the backup flange. Make sure you clean off the leftover putty.

Step 3: Connect the Drains and Power Cord

Connect the dishwasher drains to the disposal unit by first unblocking with a hammer and a screwdriver. Before unblocking, remember to remove the plug from the inlet of your disposal unit. Connect the power cord by removing the cover plate and matching the wires with their respective colors before reattaching the cover plate.

Step 4: Install the Garbage Disposal

Now it is time to install the entire disposal unit under the sink. You can do this by inserting the gasket to the discharge outlet, connecting the discharge tube to the flange, and screwing the bolts for a firm fitting.

Align the three taps of the disposal with the mounting ring. Using a wrench, turn and lock the taps securely over the ridges. Connect the dishwasher drain and make sure the discharge tube is fixed properly before connecting the other drainpipes.

Step 5: Test

Before you fold your tools to go, make sure you have tested the disposal unit to ensure it is working properly. Moreover, check for any leaks by running water from an already filled sink.

Installing Badger Disposals

The process of installing a badger disposal unit only requires you to have a few tools and the materials needed. Check out the simple steps below!

Step 1: Turn off the Electrical and Unplug the Drains

Before you even start installing your badger disposal unit, make sure the place under the sink is clean. Turn off the electricity to the sink. Get a bucket under the sink to hold any water that may leak as you unplug the sink drains. If you have a dishwasher connected, you need to disconnect it as well. Remove the old sink drain by unscrewing it, move to the old disposal unit, and remove it by rotating it anticlockwise.

Step 2: Remove the Old Unit

When you have removed the flange, you will realize that there is old plumber’s putty around where it was attached. Scrap it off gently with a putty knife or a fine wire for one that is stubborn to remove. Get the new flange and smear putty around the underside where its threads meet with the sink rim. This is meant to seal the sink against leaking. Place the flange in the sinkhole and push it to fit firmly. Afterward, wipe off the excess putty from the hole.

Step 3: Prepare for Installation

Once the drain is in place, put some weight on it to keep it in place in order to install the mounting pieces without disturbing the drain. Carefully arrange the flange, mounting ring, and the snap ring and screw them to hold them securely beneath the sink.

Step 4: Install the Unit

This is now the time to bring in your badger garbage disposal under the sink. First, align the unit to the drain system before turning its mounting tabs until they hold firmly into place. Start to connect the dishwasher pipe and other drains to the respective openings on the disposal. Additionally, ensure the wiring is done well. Moreover, tighten all the fitting to ensure everything is perfectly in place.

Step 5: Test

After tightening all fittings, plug in the power cord and test whether your badger garbage disposal unit is up and running as expected.

Installing Insinkerator Disposals

Prior to installing an Insinkerator, it is recommended that you read and understand the installation instructions and safety precautions that accompany your unit. Here are the steps to follow when installing an Insinkerator under your sink.

Step 1: Detach the P-trap and Drainpipes

Loosen the nuts that hold the pipes into place and remove the parts once the nuts are off. Clean the pipes to do away with all manner of clogs. You can also disconnect the down drain pipe that comes from the sink and the p-trap. Make sure to remove the strainer too by unscrewing the large nut under the sink.

Step 2: Preparing for Installation

With the help of a screwdriver, you can loosen the mounting assembly by loosening the 3 crews holding it into place and then removing the snap ring. Remove the plumber’s putty that has aged before applying a fresh one around the drain opening. Fix the new sink flange through the sink opening and push it to hold firmly.

Step 3: Install the flanges and the Gasket

Turn your attention to the underneath of the sink and fit in the fiber gasket, the backup flange, as well as the mounting flange onto the sink flange. Keep all the components firmly into place and then slip on the mounting ring followed by a new snap ring. Ensure your mounting assembly and other pieces are tightly seated beneath the sink.

Step 4: Connect the Dishwasher and Electrical

If you intend to use a dishwasher, you need to knock out the dishwasher plug with a hammer and screwdriver. Additionally, remove the knockout plug that is loose inside the disposal unit. Afterwards, lay down the unit and connect the power cord from the power mains. Ensure you do the wiring correctly to avoid short-circuiting and damaging the unit.

Step 5: Installing the Disposal unit

Align the disposal unit to the three mounting tabs by hanging it while the slide-up ramps are on the mounting ring. Start by turning the lower mounting ring and lock the tabs into the mounting system. Once you lock them in, insert the discharge tube into the coupler and slide the clamp over the tube. Slightly turn the disposal unit until it aligns with the drain trap in order to fit it perfectly. Finish by locking the unit into place. You can then insert the Quite Collar Sink Baffle into the sinkhole and push it until it snaps into place.

Step 6: Test

Fill the sink with water and allow it to run while checking for leaks. Moreover, switch on the electrical to see how it operates.

Installing Waste King Disposals

Like the other disposal units mentioned above, installing a Waste King Disposal is also simple thanks to its precise installation guidelines. You just need to follow the five easy steps below when installing a disposal unit from Waste King.

Step 1: Disconnect the Existing Drain and Strainer

Start removing the existing drain by disconnecting water and electricity from the sink.r Moreover, remove the drain pipes that are connected to the sink right at the threaded fitting. Proceed to disconnect the sink strainer.

Step 2: Install a Flange and Mounting Assembly

Before installing the flange, roll the plumber’s putty around the base where it meets with the sink. Fit the flange securely and firmly to the drain hole of the sink. Turn under the sink and install the mounting gasket and retaining ring on the flange just as instructed by the manual from the manufacturer. Make sure the screws are tight enough to hold it firmly. Clean the excess putty from around the flange on the upside of the sink.

Step 3: Mounting the Disposal

At this stage, mount the disposal unit as per the guidelines of the manual. Connect the drainpipe and the dishwasher pipe if you have it. Fit the disposal flange onto the mounting bolts and attach the discharge tube securely. Ensure you also connect the power cord before screwing the disposal onto the mounts. It is advisable to do the wiring at this stage before firmly mounting the disposal unit.

Step 4: Attach the Waste Pipe

Attach the P-trap to the drain. You may cut the P-trap if need be in order to fit it in perfectly. Ensure that the waste pipe and the dishwasher pipes are also fitted firmly.

Step 5: Test

This is the time to test whether your unit is operational. Fill the sink with water and allow it to run down the drain to check for leaks. Additionally, turn on the power to see how it grinds.

Regardless of the model or brand of garbage disposal, following the right installation procedure is the only way to have your unit up and running efficiently. Make sure you read and understand the instructions provided in the manual guide before you start the installation process.