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

A well-organized home has a distinct atmosphere. However, because most of us live in small apartments, we must make the most of every inch of available space. We still have to cope with one of the most unpleasant issues: food waste. Installing a garbage disposal under your sink could be the solution, but what about the dishwasher? Typically, we connect a portable dishwasher’s disposal line to the sink’s disposal pipe under the sink. Because you’ve inquired if you may put the garbage disposal and dishwasher under the double kitchen sink, the short response is “yes.”

When plumbing your double kitchen sink drain line, be accurate.

Double kitchen sink plumbing is substantially more complicated than single sink plumbing, despite the fact that they both have a single drain. Before they “tee” together to go down the one drain, you must add a drain assembly to the bottom of each sink. That means if you don’t do it correctly, you’ll have more trouble. A double kitchen sink setup also means you have twice as many problems to deal with. As a result, you must be very careful during plumbing to avoid any constraints or blockages. With a double kitchen sink drain design, there are twice as many spots where water can leak.

The rationale for implementing a waste disposal system is as follows:

 A garbage disposal is usually installed under the sink in most modern kitchens. Furthermore, if you don’t already have one, you should be aware of all the benefits of doing so right now. Garbage disposals can help break up food residue that builds up in your sink and drain, allowing you to do the dishes faster and with fewer clogs. This is a fantastic addition for individuals who care about the environment. You may be able to lessen the amount of trash that ends up in landfills by breaking up more food waste and flushing it down the toilet.

More food gets disposed of by the garbage disposal, resulting in less food being wasted away. This means you’ll have fewer rodents and rats in your home if you live in a city. Because of the odour of food scraps, there is no need to be concerned about wildlife foraging through your rubbish in suburban areas. Another great advantage of having a trash disposal under your double bowl kitchen sink black is that it can deal with the harm that large chunks of food waste can do to your plumbing, resulting in fewer plumbing disasters and repairs.

Are garbage disposals worth it?

Installing a garbage disposal has a lot of advantages. They assist in preventing clogs by removing food that would otherwise enter the drainage system. As a result, because the pipes are now protected against clogging, there will be less repairs required. This can help you save a lot of money on plumbing repairs. Garbage disposals are not only great for your home and drainage system, but also help prevent your food scraps from going into the sewage and landfill. It’s a simple solution that helps homes manage their food waste better. 

Tools Required to Plumb a double Kitchen Sink With a Garbage Disposal?

double kitchen sink with a disposal and a dishwasher

Several common tools, such as the following, are required prior to installing the plumb:

  • Hacksaw
  • Hammer piles
  • Hex wrench
  • Screwdriver 
  • Plumbers putty
  • Pipe Cutter
  • Hammer plies
  • Pipe Wrench
  • A rag or an old piece of cloth.


  • Cement
  • P-traps
  • Dishwasher unit
  • Disposal unit

For the murky water left on the dishwasher to drain and leave you with a clean dishwasher, you’ll need a disposal system. Many people feel that installing a double basin undermount kitchen sink, disposal, and dishwasher in a kitchen is difficult. It isn’t, as the following procedure demonstrates:

Turning off the water supply

This keeps the double kitchen sink from overflowing. Before you begin, make sure the water supply to your sink is turned off.

Drilling a hole

Make a hole in the double kitchen sink with a drill. The diameter of the hole should measure since the air gap stem should fit into it.

Installing the air gap

 Pass the air gap with a rubber washer on top through the sink kitchen hole. Place the second rubber washer on the air gap system to guarantee that the air gap remains watertight and airtight. Hold the stem with one hand to keep the air gap tight as you tighten the compressor nuts. Tighten the compression nut under the sink with the wrench while holding the air stem tightly with pliers.

 Placing in the disposal pipe

 The dishwasher disposal line should be routed through the tiny air gap system that has been installed. You’ll need compression nuts or a high-quality water hose clamp for this. Check that the nuts and clamps are securely fastened. The disposal pipe should also be in good condition to ensure that murky water reaches the air stem every time.

Bridging the air gap and installing a twin double kitchen sink

Take a measurement from the air gap stem’s second outlet to the double kitchen sink drain pipe. Use a disposal hose that is larger than the measurement to improve flexibility. Cut the disposal pipe to the appropriate length and connect one end to the air system’s second outlet.

Using a wye in the dishwasher

Take a measurement of the wye’s length. Cut the pipe that will join in the right place. To properly set up the dishwasher, make sure the inlet pipe is facing upwards and the dishwasher is facing the war. Connect the why to the sinking bridge with nuts and washers to provide a watertight connection.

Join the wye to the drain pipe

Connect the wye to the other end of the ordain pipe that comes out of the air stem inlet. This keeps undesirable odours from escaping the input pipe and polluting the kitchen area. 

Turn on the Water line

Your double kitchen sink with disposal and dishwasher is complete once you attach the drainpipe to the wye. Turn on the water and check if everything you have done is working.

How to Install a Garbage Disposal in 10 Easy Steps

Before you install a garbage disposal, make sure you’re familiar with all of the components. It would be difficult for you to comprehend otherwise. Then, before you begin the installation, begin assembling all of the parts to ensure that they fit together perfectly. So, here are some easy steps to follow:

1. Plumber Putty: 

 Apply a layer of plumber’s putty to the flange. Then lightly hold and press to keep everything in place. Plumber putty is necessary for repairing and replacing plumbing equipment as well as preventing leaks in any plumbing operation.

 2. Flange Movement: 

 Set the garbage disposal on the collar of the garbage disposal to prevent it from moving. The flange provides a strong hold on things, preventing them from falling apart.

3. Place everything in the collar:

Pile up the flange and fiber gasket along with the mounting ring.

Then slide everything lightly into the underside of the collar to assemble things before setting.

4. Snap Rings:

 After you’ve put everything in its place, tighten the snap ring with the screws. It aids in the proper placement of everything.

5. Clean-Up: 

Using a rag or an old piece of cloth, remove any excess plumber’s putty. Separate out any materials that will no longer be used.

6. Electrical Cord:

Remove the wire cover plate to gain access to the electrical cord. Then match the wire colors and connect them properly. After the wire colors are connected, reattach the wire cover plate. You can connect them to a circuit in one or two directions.

7. Drain Plug: 

Make sure to use a hammer to remove the drain plug. Otherwise, it has the potential to open up.

8. Discharge Outlet:

 Connect the drain to the discharge outlet and insert the gasket with a gentle touch. Make sure to install bolts and a flange to secure the discharge tube.

9. Mount Ring:

 The disposal hangs from three tabs after aligning the mounting ring. Use the hex wrench to secure the tabs. The tabs must be locked or else they will fall apart in the mounting ring.

10. Connection to the dishwasher:

To complete the installation, connect the dishwasher drain and discharge pipe.

Why is dishwasher drainage so important?

Once your dishwasher has finished cleaning, empty the dirty water into your home’s drainage system. Without proper drainage, the dirty water will contaminate your dishes once more, making the problem worse. If you want your best countertop dishwasher to work properly, you’ll need to install a proper drainage system that allows dirty water to flow smoothly into the drain.

The Tools Required For Installing A Dishwasher On A Garbage Disposal?

The following are the most important tools to have on hand when installing a dishwasher in a garbage disposal:

  • Air gap fitting
  • Dishwasher install kit
  • Screwdriver
  • Light hammer
  • Utility knife
  • Two more rubber compression washers
  • One inch hose clamp
  • Two compression clamps

Why is installing a dishwasher drain important?

Your dishwasher drains dirty water into the kitchen’s drainage system after it has completed washing dishes. Without proper drainage, dirty water could back up and contaminate the dishes, which would be extremely unpleasant. Your countertop dishwasher must have an efficient drainage system to ensure the smooth flow of dirty water away from the appliance.

Installing A Dishwasher: 10 Easy Steps

Continue to carefully follow these 12 steps. You won’t be able to install a working dishwasher otherwise. 

1. Turn off the water supply:

 You must turn off the water supply before beginning the installation process. If you don’t turn off the water supply, water will spill out all over your workspace while you work.

2. Disconnect the garbage disposal: 

 Unplug the garbage disposal first from the electrical outlet. Working without unplugging the garbage disposal is dangerous because it is connected to an electrical cord.

3. Unplug the knockout plug: 

Locate and remove the knockout plug with a screwdriver and a light hammer.

4. Remove the hose nozzle: 

 Lose both ends of a hose and try to remove it. Then, by turning the hose nozzle clockwise, unscrew it. Then remove the hose nozzle with a needle-nose plier.

5. A fitting washer:

 Softly thread a thread above the air gap and up to the back of the sink’s hole. Tighten the runner washer at the trim cap with your hands.

6. Adjust the angle of the nozzle:

 Continue rotating the air gap fitting with your hands until the angled nozzle is pointing in the garbage disposal’s direction. Slide one side of the disposal drain towards the dishwasher’s nozzle.

7. Clamps for hoes:

The hose clamps at the end of the hose should be tightened. Using a screwdriver, tighten the lower hose clamps.

8. Ensure the hose is properly installed: 

Cut the upper side of the hose perfectly with a utility knife. Make sure it fits the air gap nozzle perfectly.

9. Make sure the vertical nozzle is tight: 

To prevent the hose from bending at the vertical nozzle, insert a 1-inch hose clamp on the other side of the hose clamp.

10. Installing the dishwasher:

After inserting the vertical nozzle, tighten it with a hose clamp. Then your dishwasher will be installed in its entirety.


Food waste is one of the most revolting issues we still have to deal with. Getting disposal under your sink could be the answer. It is simple and feasible to install a double kitchen sink with disposal and a dishwasher. Connect a dishwasher’s disposal line to the sink’s disposal pipe under the sink, and it’s connected to the garbage disposal.

All you have to do is adhere to the guidelines outlined above. Before you begin the installation process, make sure you read the manufacturer’s instructions and follow them exactly.

Frequently Asked Questions (FAQs)

Should the dishwasher connected to the garbage disposal?

Connecting your dishwasher drain to your garbage disposal will help you simplify and make things easier in the kitchen. You will need to dispose of the leftovers of the food while washing the dishes in the dishwasher, and having the garbage disposal connected helps to solve the problem. It aids in the reduction of trash in the kitchen, which can attract insects such as cockroaches and rodents.

Can a dishwasher drain directly into the waste line?

Yes, a dishwasher can drain directly into a waste pipe beneath the floor, but this has the potential to cause numerous issues. It is also critical that the drain is connected to a proper fitting with a trap that prevents sewer gases from entering the dishwasher.

Can I run my dishwasher drain into the sink?

Yes, it is very possible with the correct dishwasher and waste disposal installation. However, if it is not install in the right way, or one of them is damaged or broken, operating the dishwasher and the garbage disposal simultaneously may become an issue.