How Do You Cap Off A Dishwasher Drain Line?

You might be renovating your kitchen and installing a new dishwasher, or your dishwasher’s drain is damaged or misaligned. Or you are using a garbage disposer, and you need to connect your dishwasher with it. In any case, it is mandatory to cap off your dishwasher’s drain line to make the process hassle-free. 

Based on your requirement, you can seal the drain line temporarily or permanently by covering it with a rubber or a copper cap.

The capping process begins by cutting the drain pipe and sealing it with a conical rubber cap which measures 3\4 inches in width. It is as simple as pushing this conical rubber into the drain pipe. You can also use a copper drain cap and seal the outlet by screwing it in place.

You can easily cap off the drain pipe. Still, it’s crucial to acknowledge the step-by-step systematic process to make the operation easy and effective.

In this article, I will help you understand the step-by-step process to cap off your dishwasher’s drain line. At the end of this article, you can cap off your drain line even if you are unaware of the technical side of dishwashers.

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What is the drain line in the dishwasher?

Before jumping into the solution, if you are wondering what a drain line is, it is the system that the dishwasher uses to drain off the water after every wash cycle is completed.

A drain line consists of a pipe or a hose that is located under the dishwasher.

You can take out the dishwasher to reach out to the drain line.

How does the drain hose work?

Usually, the dishwasher’s drain leads to a garbage disposal that contains valves to pull off the dirty water after every wash cycle.

When installing your new dishwasher, you must seal the drain pipe to make the sink convenient.

Otherwise, you will end up flooding the kitchen floor.

If not, still, it’s better to cap off because you might unknowingly turn on the pipe that will mess up your kitchen floor, as I mentioned before.

If your kitchen floor is wooden, you might be extra cautious to avoid this mishap. 

Dishwashers have different types of drain line connections.

You must understand the drain connection to make the operations precise and successful. 

The dishwasher drain may be connected to the air gap to lead to the garbage disposal.

It can also be directly connected to the drain without the air gap or the garbage disposal.

Another type of configuration is the high loop connections. 

There will be a high loop connection either to the drain directly or through the garbage disposal.

Check your dishwasher for the connections mentioned above to make the process simple.

How do you cap a drain line?

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Here comes the solution which you are looking for.

As I said in the beginning, it’s easy to cap off your dishwasher drain.

Still, a basic understanding of the drain line and the step-by-step guide will help make the process even more effective. 

In case of renovation, you can go for the temporary sealing in which you can remove the cap to connect back to the dishwasher later.

You can find methods for both temporary and permanent sealing.

Also, you can use the below-listed methods to seal off leaking and damaged pipes.

Capping drain line temporarily:

If you are cleaning the kitchen or painting the house, you can use this method if your dishwasher is damaged and you want to detach it to fix the issue.

It can be any reason.

Here are the important steps mentioned for you to follow while capping off.

Follow these steps for the successful operation of capping off the drain line.

  1. Disconnect the water supply: Imagine what will happen if the water supply is on while operating the drain line area. Water will flood the kitchen area, and you cannot fix the cap properly. Cutting the water supply is simple. You have to turn off the water supply button near the button.
  2. Measure the drain pipe: After the water supply is disconnected, use a measuring tape to measure the particular drain pipe you have to seal or cap off. Consider avoiding random measurements without using the measuring tape. Precise measurement will lead to the proper sealing of the drain line.
  3. Cut the pipe: After measurements are done, it’s time to cut the measured area. You can use a hacksaw to cut the pipe. Ensure the precise cutting procedure.
  4. Clear the pipe: Now, you can see so much dirt and debris deposited inside the pipe. The next step is to clean it. You can use hot water, baking soda, or vinegar to clean the pipe. Use baking soda and vinegar to put at the bottom of the dishwasher. Let it sit for 20 minutes. After that, run hot through it to clear the debris and dirt.
  5. Smoothen the edges: You can see the rough and unequal edges after cutting the pipe. This will cause the detachment of the cap. Use an emery cloth to smoothen the edges.
  6. Fix the cap: Here comes the important step of mounting the cap into the drain line. You can use a conical rubber cap of 3\4 inch width or a copper cap of 1\2 inches to seal your dishwasher drain line.
  7. Time for a final check: Check if the cap fits properly to the drain line. Before mounting the cap, it’s important to check the dimension of the pipe and the cap are aligned. If not, try fixing it or ask for professional help if you feel you need it. 

Permanent capping of the drain line:

If you are facing the issue of leaking pipes or some unused pipes, then you can choose the permanent capping-off method.

You should consider capping off the leaking pipes because it may make the kitchen messy, thus making it unpleasant to work. 

This permanent capping method is a little more complicated than the temporary method.

Follow this method for effective results:

  1. Disconnect the water supply: It also starts with cutting off the water supply. It will make the pipe fix sturdy. Switch off the water supply button to hurdle-free capping.
  2. Measure and cut the pipe: Locate the damaged or leaky pipe. Then use the measuring tape for the precise measurement. Measure the area you need to cut. After successfully measuring, use a hacksaw to cut the particular area which is damaged.
  3. Clean and smoothen the pipe: After cutting the pipe, use baking soda, vinegar, and hot water, as mentioned in the previous process, to clean the pipe. Now smoothen the edges of the rough pipe to align the cap and the drain pain well.
  4. Coat with the primer: After thoroughly cleaning, coat the exterior and interior parts of the pipe with primer. Prime will initiate the chemical reaction to soften the pipe to prepare the cement coating. After applying the primer, cement will hold the pipe tight. Allow the primer to dry.
  5. Apply the PVC cement: After the primer coating is done, apply the cement. As you are permanently capping off the drain line, cement will prevent the long-term leak. Apply the PVC cement to the cap’s sides and pipe. Pull the cap onto the drain pipe to fix it properly. Keep it undisturbed for 20 to let it dry.
  6. Final step: Check if the leaking is fixed or not by turning on the water supply. If the water is not leaking, the issue is fixed. If it’s still leaking, try to find what went wrong. In case you couldn’t figure it out, seek professional help.

Why do you need to cap off the drain line? 

Capping off the drain line is important in many circumstances.

Here is the reason why you should consider capping off the drain line.

  • Save water: Let’s say your pipe is damaged and leaking. In that case, water will keep flowing, increasing the water bill. Also, the continuous water flow will make your kitchen messy and hinder your day-to-day kitchen activities.
  • No additional expenses: Capping off the dishwasher is not an expensive process. You can do it yourself by following the two effective methods mentioned above.
  • Hassle-free repairs and renovation: If something goes wrong with your dishwasher or you are renovating your home, capping off the drain line will prevent any hurdle. You can seal your drain pain by just capping the ends.
  • Prevent damaging the pipes: A continuous flow of water will damage the pipes, thus leading to the replacement of it, which will cost you money. Also, the water flow will fill the nearer area with salt deposition that will affect the look of your kitchen. 

How to remove the cap?

If you are done with renovating or installing the new dishwasher, you want to remove the sealed cap.

Follow these steps to pull the cap back. 

  1. Disconnect the water supply: It’s always better to start any process by switching off the water supply. It will prevent the mess from happening.
  2. Removing temporary cap: Use an adjuster tool to pull the cap from the drain line. Mostly, you can pull it with your hands. 
  3. Removing permanent cap: Removing a permanent cap is not as easy as removing a temporary cap. As the cement is tightly attached to the cap and drain line, you can’t pull it off easily. Use a saw to cut the joining of the pipe and the cap. To smoothen the end, use emery cloth. 

Effective ways to clean the dishwasher drain line

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Keeping the drain line clean is always best to avoid clogging with debris and food particles.

You can use these methods to keep the drain line of your dishwasher clean. 

  • Garbage disposal cleaning: If the garbage disposal of your disposal is filled with filthy water, it will cause the water to come back. This will cause a draining problem in the dishwasher. Remove all the clogs and run the hot water through to make the garbage disposal clean and empty.
  • Air cap check: You can locate the air gap installed near the sink and countertop. This will prevent the sink water from entering the dishwasher. If there is a build-up on the air gap, that will cause a draining issue in the dishwasher. Remove the air gap to check for any debris deposits. If you find any deposits on the air gap, run the hot water, you can also use baking soda and vinegar if the deposit is very stubborn.
  • DIY solution: Baking soda and vinegar are the best ingredients that we can use to remove the clogs in the drain line. Pour the vinegar and the baking soda mixture into the bowl and run it through the drain pipe for 20 minutes. 

These are the ways you can ensure the cleanliness of the drain line of the dishwasher.

Final thoughts

Capping the drain line helps you save water and prevent damage to the pipe or chances of water spillage on the kitchen floor. The best thing is you can do it yourself without the help of a technician or plumber.

I have explained the two ways of capping off a dishwasher drain line in this article, and you can try any of these as per your convenience and requirement. I have also explained how to remove the cap as and when needed.

Reference: Home Plumbing CDC guidelines

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Jeniffer Smith

Hi, I am Jeniffer Smith, a housemaker and blogger, and I grew up in Shrewsbury, Massachusetts. I have been researching and fixing appliances and other things around the home and kitchen from a young age to help my single mother. Every time something went wrong, I couldn't rest until I fixed it. And ever since, I have enjoyed fixing things around my home, and I am always ready to help my friends and family with advice and hands-on help. Since we were always looking for affordable ways of fixing things, we rarely hired experts and tried to fix most things ourselves. That interest brought me to write for this blog, as I realized my knowledge could help many people trying to fix things around their homes on their own without spending hundreds of dollars.

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