Best Guide: How to Plumb a Double Kitchen Sink With Disposal and Dishwasher (Updated 2022)

In the event that you’ve just acquired a new dishwasher and want to attach it to a garbage disposal in order to ensure proper drainage, you’ve arrived at the perfect place.

Garbage disposals and dishwashers are often connected to a kitchen sink so that water could be properly drained when the washing phase is finished.

Homeowners often encounter significant difficulties when attempting to install these two vital appliances, which is particularly true when attempting to install a double sink.

Nevertheless, if you have a garbage disposal linked to your double sink, the mechanism would already have a connection for the dishwasher sewer line built in.

Therefore, the procedure of plumbing a double kitchen sink that includes a dishwasher and a garbage disposal is somewhat straightforward.

How to Plumb a Double Kitchen Sink With Disposal and Dishwasher

How to Plumb a Double Kitchen Sink With Disposal and Dishwasher

Incase your double sink water system already includes a garbage disposal, connecting a dishwasher drain is a straightforward task since the disposal is already equipped with an outlet that is particularly built for dishwashers.

Follow the following procedures to properly plumb a double kitchen sink that includes a garbage disposal and a dishwasher:

Step 1: Turn Off the Water Supply

Whenever you begin, turn off the water supply to your home altogether.

Step 2: Make a High Loop

  • Make a high loop with your dishwasher drain pipe by running it up and around it many times.
  • When using a dishwasher or sink, it is critical to ensure that the loop is set as high as possible to prevent water from flowing backwards into the dishwasher.
  • Because when the loop is divided by a wider distance, the pressure buildup causes the system to shut down, stopping the water from returning back to the dishwasher.
  • Furthermore, if the twist is not installed at an appropriate height, it may result in the accumulation of moisture and mildew, which may eventually seep into the water.
  • Later, this contaminated water would be used to wash your dishes, which you do not want to happen.

Step 3: Maintain the Loop

  • During this stage, just tying a high loop will not be sufficient to keep it in place for the whole process.
  • As a result, you will need to use a bracket or a clamp to maintain this high loop in place.
  • The most secure area to make the knots would be behind the countertops or against the back ends of the walls in the corner present between the wall and the counter.
  • Next, you must pinch the loop that is formed between the wall and the counter as tightly as possible.

Step 4: Connect the Disposal Inlet

  • Then, you have to connect the disposal inlet to the drainpipe’s end.
  • Connect the pipe to the disposal tube by using a hose clamp, compression washer, or nut to hold it in place.
  • All of these fastening supplies should be included in the set of installation components that come with your dishwasher.

Step 5: Check For Leaks

  • Activate the water supply system.
  • You can turn on the water system provided that everything has been properly fastened.
  • Operate your dishwasher to see if there is any evidence of a leak. As long as there are none, you’re fine to go.
  • Incase, you notice any leaking, adjust the compression nuts to complete the task.

And there you have it! You’ve completed one of the most fundamental tasks that most double sinks enable you to do. Ideally, you will not be required to spend more than one hour on the task.

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How to Plumb a Double Kitchen Sink With Dishwasher and Without Disposal

How to Plumb a Double Kitchen Sink With Dishwasher and Without Disposal

A dishwasher that has just been installed requires both a water source and a place to drain. Incase, you do not have a garbage disposal, you must attach the sewer line to your double sink drain to ensure that your dishwasher drains effectively.

It is possible to install a drain fitting that is specifically built for this reason, rather than having to replace the complete drain system below your sink.

Step 1: Shut off Water Supply

  • Shut off the water supply to prevent any potential issues or the possibility of anyone turning on the faucet when you’re in the midst of your job.

Step 2: Find the Slip Nut

  • If you have a double sink, you have to pick a drain that is near your dishwasher installation to ensure that you can connect it. 
  • Find the slip nut that joins the sink drain‘s tailpiece to the strainer basket.
  • They are usually located below your sink.
  • Pump pliers could be used to release the slip nut, allowing it to glide down the tailpiece.

Step 3: Remove the Tailpiece

  • Remove the tailpiece from the drain basket and look for the second slip nut, which should be located at the bottom of the tailpiece.
  • You can use pump pliers to remove this nut.
  • Remove the existing tailpiece from the sewer line that links the two sink drains and store it somewhere safe.
  • The slip nut that was used to join the tailpiece to the drain basket should be removed, and the nut that was present at the bottom of the tailpiece should be left in place.

Step 4: Cut PVC Dishwasher Wye Tailpiece

  • Calculate the length of the existing sink drain tailpiece with the help of a measuring tape.
  • Next, trim a PVC dishwasher wye tailpiece to fit using the preceding measurement.
  • You can create cuts using a hacksaw and finish by smoothing the corners with 320-grit wet/dry sandpaper.

Step 5: Remove the Slip Joint Washer

  • Remove the slip joint washer present in the slip nut.
  • This is the slip nut that you previously left in position. Now replace it with a new rubber slip joint washer.
  • Connect the cut finish of the PVC dishwasher wye tailpiece to the slip nut on the drain line.
  • You can use  pump pliers to fasten it .
  • Connect the dishwasher wye’s head to the drain basket’s bottom.
  • Additionally, the wye will have a new slide nut and washer attached to the head.

Step 6: Insert Drain Hose Clamp

  • Install the slip nut and washer on the drain basket by slipping them up the wye and turning them clockwise.
  • With pump pliers, twist the nut even further.
  • Plug a drain hose clamp into the drain line.
  • Next, run the drain line above the tiny pipe protruding from the dishwasher wye tailpiece, which you have recently mounted in the double sink.

Step 7: Tighten the Screw

  • Twist the screw present on the hose clamp to secure your dishwasher drain line to the sink drain.
  • Switch on the water system and check to see that the drainage is perfect.

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Whether You Need an Dishwasher Air Gap or Not ?

How to Plumb a Double Kitchen Sink With Dishwasher and Disposal

Whenever you start attaching a dishwasher drain without a garbage disposal, you must determine whether or not an air gap is needed.

In several parts of the globe, plumbing rules require the installation of an air gap between a countertop or sink and a dishwasher. The dishwasher drain would initially join this air gap before connecting to the kitchen sink drain.

Its principal function is to prevent backflow from a dishwasher that has been fitted.

However, installing a two sink dishwasher with such an air gap isn’t quite as attractive, and it could be legally required.

If your local plumbing codes do not need an air gap, you may simply utilize the high loop stated above.

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Why is dishwasher drainage necessary ?

  • As soon as your dishwasher finished washing, it must empty the unclean water into the drainage system of your house.
  • Without adequate drainage, the contaminated water will contaminate your dirty dishes once again, exacerbating the problem.
  • If you really want your ideal countertop dishwasher to operate successfully, you must install an adequate drainage system that allows filthy and waste water to flow freely into the drainage system.

The Cost of Installing a Garbage Disposal

Before you can install a double kitchen sink with a disposal unit and dishwasher, you’ll have to spend for a few things. First and foremost, there is the garbage disposal unit.

Obviously, the price will be hugely affected by the model and brand that you use. The cost might range from $100 to more than $200.

However, if you fix it manually, you will save a lot of money. Reliable plumbers who are sure to perform a decent job may charge you the same amount for installing the systems.

But don’t fear;, installing and piping this unit is very straightforward; with a little effort and skill, there’s really no excuse why you would not be able to handle it on your own.

However, if you discover that it is too hard for you at any point, just call a professional, and they will quickly complete the task!

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Aren’t these the best ideas and tricks on how to plumb a double kitchen sink with disposal and dishwasher? We think so!

Every day, our simple guidelines may save you a massive amount of time and energy.

Furthermore, you may finally be free of the dreadful sensation of handling wet food.

Remember to include these tips into your everyday routine for the major benefits

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