Double Kitchen Sink Plumbing Diagram

The double kitchen sink has found favor in many households due to its versatility and convenience. However, plumbing can pose a challenge. But you won’t have to get lost so long as you have a double kitchen sink plumbing diagram to guide you.

To install a double kitchen sink, you need to have extra space. When it comes to plumbing, things can get a bit more complicated. While there may still only be one faucet, you would still have to install two drain assemblies. Not to mention a dishwasher that utilizes the double sink drain lines.

A double kitchen sink enables one to do the dishes on one side and to make food preparations on the other at once. Although it is twice the size of a regular sink, installation is a reasonably straightforward process.

Read on to learn more about installation and plumbing using a plumbing diagram for a kitchen sink with a double basin.

Double Kitchen Sink Plumbing Diagram

You need to have extra space to install a double kitchen sink. When it comes to plumbing, things can get a little complicated. While there may still only be one faucet, you still need to install two drain assemblies. Not to mention a dishwasher that utilizes the double sink drain lines.

Shown above are diagrams that can help you understand the basic structure of the double kitchen sink plumbing system. Note that the setup illustrated includes connections for dishwasher and garbage disposal units. We shall discuss these in the sections that follow below.

Pros and Cons of a Double Kitchen Sink

Allows One to Perform More Than One Task Simultaneously

The dual basin has become a popular kitchen sink setup. It allows one to perform more than one task simultaneously. It’s beneficial in households that do not have dishwashers.

Multi-purpose and Flexible

Double kitchen sinks are multi-purpose and flexible. They allow one to wash the dishes on one side and rinse and dry them on the other side. You can also use the space to prepare food, such as rinsing fruit, vegetable, and meat or peeling potatoes and carrots.

Not Big Enough to Accommodate Large Kictchenwares

A double kitchen sink brings lots of advantages. But it does carry a few disadvantages, as well. Either side of the sink is usually not big enough to accommodate large pots, casseroles, or baking pans. 

Single-basin Sinks Are Still In

Also, contemporary trends tend to favor single-basin sinks. Lastly, there are still some homeowners who aren’t very keen on the double sink’s utilitarian appearance.

How to Install Double Kitchen Sink Plumbing

It only takes at least a basic understanding and knowledge of plumbing to connect the plumbing to the base of a double kitchen basin setup. The process isn’t as difficult as it seems. So don’t let yourself get too overwhelmed.

Remember that you only have to deal with one main drain and two rather short sink drain assemblies. The two drain assemblies are the only difference between a double and a single kitchen sink. Another difference is the “tee” fitting connecting them to the main drain.

Steps

The main steps in plumbing the drain lines onto a double kitchen sink setup are the following:

1. Prepare the Tools and Materials
2. Plan How to Use Each Tool and Material
3. Connect an Elbow Fitting to the Sink Drain Spout
4. Link a Pipe End to a Tee Fitting
5. Repeat Steps 3 and 4 for the Other Kitchen Sink
6. Fasten Plumbing Line Trap
7. Connect the Plumbing from the Trap into the Main Drain Line

1. Prepare the Tools and Materials

Once the sink has been set in position, gather all the tools and materials you require for the assembly.

You will be using PVC fittings with male threaded and female slip ends. The latter also comes with a seal and pipe connector on them. In most cases, there will be no gluing involved. You will need to use Teflon tape to seal the pipe connections’ threads.

2. Plan

Try to lay down the materials on a table. This step will help you envision the materials you will connect. Also, this way, you can check if you have all the parts you need before installing.

3. Connect an Elbow Fitting to the Sink Drain Spout

Begin by connecting an elbow fitting with a long, straight end to one of the sink drain spouts. Be sure to use a single Teflon tape wrap to make a good seal. Don’t tighten the connection all the way.

4. Link a Pipe End to a Tee Fitting

Put the end of the pipe that is not connected to the sink spout into one of the “tee” fittings’ short ends. As before, don’t tighten the connection all the way.

5. Repeat Steps 3 and 4 for the Other Kitchen Sink

Repeat the 3rd and 4th steps to the other side of the kitchen sink. The sink drain spouts should then be plumbed into both of the “tee” fittings’ short ends.

6. Fasten Plumbing Line Trap

Fasten the plumbing line trap to the long lower part of the “tee” fitting, which hasn’t been plumbed yet.

7. Connect the Plumbing from the Trap into the Main Drain Line

Finally, connect the plumbing from the trap into the main drain line. After, you must tighten all connections with the channel. Be sure to use only light pressure, or else you will break them.

Again, double kitchen sink plumbing diagram – what do you need? Ensure you have extra space if you plan to install a double kitchen sink. Plus, you have to install two drain assemblies and a dishwasher with double sink drain lines.

Plumbing a Dishwasher into a Double Kitchen Sink

Much Easier Process Than You Think

You might be wondering how you can install a dishwasher drain line into a double kitchen sink. Maybe, you’re concerned that you may have to add a third drain assembly to the setup. But that is fortunately not the case. Setting up a dishwasher drain line is a much easier process than you think.

Drain Lines Are Not Bigger Than 3/4 Inches

You’ve probably never seen water draining out of a dishwasher. This is likely because dishwasher drain lines are fully enclosed and usually hidden. Dishwashers don’t use as much water as most would think. That’s why they do not require huge drain lines. Typically, dishwasher drain lines tend to be no bigger than 3/4 inches.

Plumbers Cut a “Tee” Fitting into One of the Sink

Most plumbers would just cut a “tee” fitting into one of the double sink drain lines to empty the wastewater. It’s a rather simple setup, even if you do it as part of a retrofit. If you have a garbage disposal, you should be aware that manufacturers will usually include a connection that you can easily hook up to the dishwasher drain.

Plumbing a Dishwasher and Disposal into a Double Kitchen Sink

Generally, dishwashers and garbage disposals are both attached to a kitchen sink. This is for effective water drainage once the washing cycle has been completed.

Homeowners Find It Difficult to Install a Dishwasher and Garbage Disposal

Many homeowners find it challenging to install both a dishwasher and garbage disposal into a double kitchen sink setup. But it’s a different case if your double sink is already attached to disposal. Then it should already come with an outlet specifically designed to connect to the dishwasher drain line.

Verify the Dishwasher and the Garbage Disposal’s Size

Verify the size of the dishwasher and the garbage disposal. Then measure the space under your kitchen sink. If it is a proper fit, then you may begin the installation. Make sure that you shut off the water supply first before you start.

Tools and Materials

• Pipe wrench
• Pipe cutter
• Piece of cloth
• Dishwasher unit
• Garbage disposal unit
• P-traps
• Wye fittings
• Cements

Procedure

1. Get Rid of the Previous Sink Pipe
2. Install a Wye Fitting on the Drainage Line
3. Cut the P-traps into the Proper Shape
4. Remove Traces of Previous Putty Residue and Reapply New Putty
5. Do a Test Run of Your Dishwasher and Disposal Double Sink Setup

1. Get Rid of the Old Sink Pipe

Get rid of the previous sink pipe, also known as a P-trap, because of its p-shaped curve. It is responsible for the drainage of wastewater.

To remove the old P-trap, locate the tailpiece and rotate it counterclockwise. Doing so will take it out of the wall drain. If you are working with a plastic pipe, you can easily remove it by hand. But if it is a metal pipe, remove it using a pipe wrench.

Pressure all of the nuts out and disengage the pipe from all connections. Afterward, you may move on to step 2.

2. Install a Wye Fitting on the Drainage Line

Install a wye (y-shape) fitting on the drainage line. The wye is a fitting with three openings and is used to create branch lines.

The dishwasher and the garbage disposal cannot properly function in a single drainage line. That’s why you will need to install the wye so that the single drain line will have a double connection line.

Cut the wye to fit the drain line perfectly. It should be a 1/2 inch diameter less than the connection line. After you have cut it, the wye can fit perfectly to the line to enable the installation of the disposal and dishwasher under your sink.

3. Cut the P-traps into the Proper Shape

Cut the P-traps into the proper shape to fit into the right holes. Measure the diameter of the wye. Cut accordingly to be cemented and inserted inside the wall drain.

Insert one end of the P-trap into the wye and connect the other to the sink. This will allow them to both ends up in the dishwasher and disposal units. Be sure you have made the proper measurements before cutting, or it may not properly fit.

4. Remove Traces of Previous Putty Residue and Reapply New Putty

Cut out traces of previous putty residue and reapply some new putty. Then, insert the pipes and flanges into the right holes for the dishwasher and disposal units. Add the mounting ring, and then tighten back all the nuts to the system.

5. Do a Test Run of the Dishwasher and Disposal Double Sink Setup

Do a test run of your dishwasher and disposal double sink setup. Startup the dishwasher and disposal units and check for any signs of leaking. Also, make sure that the bend of the P-traps is on the right track to function properly.

More Tips on Doing Double Kitchen Sink Plumbing

Although they both use a single drain, double kitchen sink plumbing is more difficult than single sink plumbing. You need to add a drain assembly at the bottom of both sinks before they can “tee” together to go down a single drain. You can run into even more difficulties if you don’t do it correctly.

With a double kitchen sink setup, it’s possible to have twice as many problems. Be aware that twice as many places in a double sink setup can experience clogs or leaks. So, you need to be very careful and precise when you plumb to prevent any restrictions, clogging, or leaking.

Conclusion – Double Kitchen Sink Plumbing Diagram

To install a double kitchen sink, you need to have extra space for it. When it comes to plumbing, things can get a little complicated. While there may still only be one faucet, you would still have to install two drain assemblies. Not to mention a dishwasher that utilizes the double sink drain lines.

The double kitchen sink is convenient for people who want to get their kitchen work done as quickly and efficiently as possible. It allows them to perform two kitchen tasks, dishwashing and food preparation, at the same time.

It does twice the work that a single kitchen sink does simultaneously. However, it also takes twice as much work to install it. Also, if you make any mistakes during installation, you may end up with twice as many plumbing problems in the long run.

You can always hire a professional plumber to do the installation for you. But should you opt to do it yourself, the process doesn’t have to be as complicated as it would seem.

Installing a double kitchen sink can be made easy if you have a basic understanding of the system’s design and workings. By referring to a kitchen sink with a dual basin plumbing diagram, you can familiarize yourself with it.

Also, be sure to follow the installation steps carefully. Use the right tools and materials, and practice caution while plumbing. Your double kitchen sink will only work as well as you put it together. But once you have assembled it properly, you can expect kitchen efficiency to double without any trouble.