How to Plumb a Kitchen Sink With Disposal and Dishwasher

How to plumb a kitchen sink with disposal and dishwasher? Step by step guide


Nothing is more annoying in maintaining a kitchen than dealing with food waste constantly.

Considering that, you have bought the garbage disposal for your sink. However, if you are wondering how to plumb a kitchen sink with a disposal and dishwasher, you are in the right place.

Dishwashers and garbage disposal are installed in a kitchen sink. They help drainage water including food scraps to move efficiently out of the sink after completion of each washing cycle. Luckily, it helps you save your time and energy.

You may find combining these crucial appliances to your sink somewhat challenging. However, with the right steps and essential tricks listed in this article, the task gets easier.

Here is everything you need to know about garbage disposal and dishwasher plumbing.

How to plumb a single kitchen sink with disposal and dishwasher?

The tool required to begin installing a garbage disposal in a sink without one existing disposal are:

  1. Adjustable Wrench
  2. Hammer
  3. Screwdriver
  4. Garbage disposal unit
  5. Piece of cloth

Before you begin with the single drain kitchen sink plumbing of disposal, make sure to do the following things.

  1. Turn off all the water supply in the kitchen. This helps to be certain that there is no threat of major leaks.
  2. Disconnect the pipes from the sink. You can use the adjustable wrench for doing it.
  3. Check the circuit breaker and turn it off for wiring garbage disposal.

Now, you may begin:

  1. Firstly, acquaint well with all the parts and accessories of the garbage disposal package. Also, make an effort to assemble them before starting the installation process.
  2. The first step to do is remove the old skin flange. You can do it by undoing the net that exists below the coupling. Once, it is loose enough, you would be able to pop this out easily.
  3. When it is removed, remove any residue left on the drain hole before the next step.
  4. Next, install the new sink flange of the garbage disposal. You can install the flange on the stainless steel sink with a rubber gasket which acts as a perfect seal for disposal. If your sink is of non-stainless steel, apply the appropriate plumber’s putty on the flange.
  5. After this, put the disposal unit on the drain collar.
  6. Put together fiber gasket, backup flange, and mounting ring. Slide these lightly onto the bottom of the collar. After all these things get in place, fit the snap ring and screw up the screws. Also, clean any excess putty.
  7. Uncover the wire plate to reach the electrical cord. Match the wire colors and attach them properly.
  8. As you would be using it with your dishwasher, use the hammer to knock out the drain plug.
  9. Now, join the drain by gently inserting the gasket in the disposal’s discharge outlet. Fix it with flange and bolts.
  10. Once it is done, suspend the disposal unit by making an alignment of the mounting ring with three tabs. To tighten the tabs onto the ridges, use the adjustable wrench.
  11. Reconnect the pipes to the new waste disposal unit.
  12. Connect the dishwasher line to the designated hole in the disposal.
  13. With everything in place, you can now enjoy your kitchen maintenance with no sink clogging.

If you are wondering about a double kitchen sink with garbage disposal plumbing, you can do it as well easily. You can do it by running its discharge tube straight to a tee below the next adjacent sink. To drain properly, the tube must drop about ¼.

How to install a dishwasher to garbage disposal? 

After the installation of garbage disposal, you can connect the dishwasher drain with the home’s drainage easily. It is because the disposal has a specific outlet for dishwashers. Below is your guide on how to plumb a dishwasher.

You will need the following tools.

  1. Screwdriver
  2. Compression clamps
  3. Dishwasher kit
  4. Hammer
  5. Air gap fitting

Installation process

  1. Turn off all the water supply.
  2. Unplug the disposal from the electric outlet. In case, they are wired into the electric circuit, switch off the main switch.
  3. Locate and remove the knockout plug that resides in the hose nozzle with a screwdriver and lightweight hammer.
  4. Put inside a threaded stem through the top of the air gap fitting into the hole that exists at the back of the sink. Insert the runner washer and fit it on the trip cap by using your hands.
  5. With your hands, rotate the air gap fitting unless the nozzled points are in the direction of the disposal unit.
  6. Now, push a side of the disposal’s drain hose upon the nozzle of the dishwasher. Tighten the hose clamps located on the hose’s opposite end. Also, insert the 2nd clamp (lower) on the nozzle and fit it by employing a screwdriver.
  7. Make sure the hose fits perfectly in the air gap nozzle without any bending. You can cut off the hose to any sizeable length.
  8. At the successful completion of these steps on how to plumb a single bowl sink with disposal and dishwasher, your dishwasher and disposal are all set to be used.

Note that the answer to how to plumb a double sink with disposal and dishwasher is also the above-mentioned process.

Sometimes, if you experience disposal waste backed up into your dishwasher, try pouring boiling water down the disposal unit every week. It prevents of clogging of the drain hose that links disposal and dishwasher.


With our guide on how to plumb a kitchen sink with disposal and dishwasher, we are confident that you can get these installed easily.

With these installed, you don’t need to pick up food scraps by hand from the sink. Neither, you will keep calling a plumber for sink clogging.

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