How to Install a kitchen Sink Drain
Before you can install a Kitchen Sink Drain, you should know what a kitchen sink drain looks like. Although I have used ABS (acrylonitrile butadiene styrene) pipes and fittings in this example, the same fittings are available in PVC (chlorinated poly-vinyl chloride). The main difference is that ABS is better in cold weather, but PVC is better for outdoors and warmer climate applications, PVC will generally last longer than ABS. But, many plumbers prefer ABS because it is easier to work with when it comes to gluing it, ABS does not require a primer and the glue set much faster so there are fewer chances of error. Here are a few typical examples:
In this photo you see a typical PVC dual kitchen sink drain, that drains through the floor.
In this photo you see a typical double PVC kitchen sink drain with a Dishwasher drain inlet, that drains through the wall.
Next I would like to show you the parts you are going to need for an ABS (black plastic pipe) or PVC (white plastic pipe) drain pipe assembly. To start with, you are going to need two strainers for a double sink installation, only one if you are installing a single sink. You can see more about how to install a kitchen sink drain in this video.
Kitchen Strainers come in either metal or plastic, the metal ones usually are made of stainless steel, but some have galvanized steel or brass parts as well. You can get them in chrome, brush nickel, brass, oil rubbed bronze and stainless steel.
The size is a standard (3-1/2") and fit nearly all kitchen sinks, some laundry tubs as well as some bar sinks.
Typically, they cost between $10.00 to over $100.00 depending on the quality and the finish. You can purchase them at your local home improvement store. If the ones you would like are not available you can order them here.
Next, you will need the following ABS, PVC or brass fittings
This is a "Tail Piece" is used to link the drain assembly (strainer) to the drain pipe which is normally 1 1/2" in diameter, for kitchen drains. The "tailpiece" attaches to the "sink strainer" and slips into the "trap adapter." (see photo - ABS trap adapter, Fig. 5) The "trap adapter" is normally glued on to the drain pipe. Typical tail pieces come in brass, plastic or chrome and cost just a few dollars. They're also available in 2", 4", 6" & 8" length. Don't worry, they don't cost much.
This is a typical female "trap adapter" fitting; it is glued onto the drain pipe using ABS or PVC cement depending on which type of pipe you are using and it is used to attach the tailpiece to the drain pipe, this makes a removable water tight connection, in case you ever need to take it apart in the future.
This fitting is made of either ABS or PVC and comes in various sizes include 1 1/4" all the way up to 2" for typical household plumbing. This fitting also comes in a male version and can be used where space is at a premium.
The next fitting you will need is what is commonly referred to as "P" trap (because it looks like the letter P). The "P" trap is meant to hold a small amount of water that acts as a barrier to prevent sewer gas and odors from entering your home through the drain pipes. For this reason "P" traps must be correctly installed and used in all drain applications that are connected directly to your home's sewer pipes. A "P" trap is generally used to connect the sink drain to a wall sewer pipe inlet.
Warning - "S" Traps Are No Longer Approved for Residential Plumbing
If you have a sewer pipe inlet that is coming straight up from the floor below the sink, then you will need to use an "S" trap as pictured here. "S" traps do the same job as "P" traps so you should use one or the other, not both. This trap comes in both PVC and ABS.
The code now requires you to use a "P" trap even for through the floor drain. The following diagram will illustrate exactly what I mean. Notice how the "P" trap is first connected to a short length of straight pipe before it is hooked up to the vertical drain pipe. This is done in order to break the siphoning action that is normally created by a straight "S" trap connection.
This type of drain connection also allows for the installation of an "AAV" (air admittance valve) should venting be required.
There are many alternatives when it comes to installing a "P" trap, these may vary in accordance with your local building codes. I recommend you check with your local building inspector to find out what is considered acceptable in your area.
Plumbing Vents: Code, Definitions and Specifications
See my Plumbing Vents, article of April 30,2015; on plumbing vent codes, definition and specifications for more on how to install a Kitchen Sink Drain.
This is a 1 1/2" ABS coupling. A coupler is used to join two pipes together. There are many types of couplers available, some are reducing couplers (used to join two pipes of different diameter together), some are threaded coupling, some are "union" type coupling (the one's that can be taken apart) some are made of ABS, some are PVC and still some are made of metal or rubber. You would use a couple like this one to join you sink drain pipe to your sewer drain pipe.
In order to better understand just how all of this fits together, have a look at the above diagram. It contains nearly everything we covered in this article about "How to Install a Kitchen Sink Drain." Note that the diagram shows a dishwasher "waste nib" this is sometimes referred to as a dishwasher "barb" connector. Since, I have not mentioned this type of connector in this article, I plan to cover it, in more detail in a future "How to Install a Dishwasher" post. The diagram is for a typical single kitchen or laundry tub installation. You will need to modify it a bit if you are installing a dual kitchen sink.
Kitchen Drain Installation Instructions
Follow these directions for a typical out of the wall drain assembly.
You should dry fit everything before proceeding with gluing all your parts, just to make sure that everything will fit perfectly.
Step 1: Install the strainer(s) Fig. 3, into the bottom of your sink. Keep in mind that the cardboard washer goes on last, just before the nut, it primary functions is to act as a lubricant for the large nut, it keeps the rubber from twisting as the nut is being tightened.
Step 2: Attach the "Tailpiece" Fig. 4, to the bottom of the sink strainer making sure to properly install the "Tailpiece Washer" (see Fig 3).
Step 3: Slip the "Trap Adapter" Fig.5, onto the "Tailpiece", Fig. 4, and tighten slightly.
Step 4: Slip the "Coupler" Fig. 8, onto the sewer drain pipe coming from the wall, remember not to glue anything yet.
Step 5: Now line up the top (short side, inlet) Fig. 10, of your "P Trap" with the base of the "Trap Adapter" and line up the Outlet end (short 90° end) with the "Coupler" on the sewer drain pipe.
Step 6: Measure the distance from the bottom of the "Tailpiece" to the top of the "P Trap" (the inlet side) and add approximately 3". This will give you plenty of length for adjustments.
Step 7: Cut a length of 1 1/2" pipe Fig. 12, to fit between the "Trap adapter" and the "P Trap" as per your measurements.
Step 8: Insert one end of the pipe into the "P Trap" and the other end into the "Trap Adapter" Fig. 10a. Remember, No Glue!
Step 9: Slide the "P Trap" up the "Tailpiece" until the "outlet" end of the "P Trap" lines up evenly with the wall drain pipe and "Coupler".
Step 10: Measure the distance between the "P Trap" and the "Coupler" then add 1".
Step 11: Cut a length of pipe to be inserted into the "P Trap" and the "Coupler" as per your measurement in step 10.
Step 12: Insert the pipe into the "Coupler and the "P Trap" check for alignment. Make sure everything fits well and everything looks good. If you are happy with everything so far go on to step 13.
Step 13: Starting at the wall drain pipe glue the "Coupler" onto the drain pipe.
Tip: When gluing plumbing pipes, be sure that the surface is cleaned properly and that you apply the proper glue to both pieces of the fittings to be joined.
Step 14: Now glue the horizontal pipe to the "Coupler" and the "P Trap" outlet.
Step 15: Now check the length of the pipe going from the top (inlet) of the "P Trap" to the "Trap Adapter" if it's too long you will need to cut a piece off, if it looks O.K., you can leave it.
Step 16: If you have decided that everything looks fine so far, you may apply glue the final parts in place. Glue the last remaining piece of pipe going vertically from the top of the "P Trap" to the bottom of the "Trap Adapter".
Let the glue stand for approximately 30 minutes and you will be ready to use your new plumbing.
Congratulations, you are done!
This is a diagram showing a typical dual sink installation, note that the plumbing code (regulations) sometimes differs from region to region. You will have to familiarize yourself with your local plumbing codes in order to carry out the proper type of installation.
This is a typical 1 1/2'' piece of ABS pipe. You can use PVC if you local codes call for it. You will need this to join your fittings together and attached it to the main drain.
ABS cement is used to glue the joints together if you are using ABS tubing and fittings. If your pipe is PVC then you will need to use PVC cement and PVC cement solvent, follow the manufacturer's directions when applying.
Tip: Use the appropriate cement for your type of applications only
Note, to our readers, I have tried to make this article as clear as possible. Please feel free to add your comments and let me know if you had difficulty understanding any part of these instructions. If you have any suggestions for improvement I would greatly appreciate it if you could pass them along so that I can improve this article for our future readers. Many thanks.