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How To Install A Double Vanity Drain Plumbing? [Complete Guide]

Living in a house with more people and fewer washrooms requires an extra sink. The problem is, most houses come with only one sink. 

Now, installing a new sink is not a problem at all. But what should be our move when you have only one drainage system? You need to turn that into a double vanity drain system.

How to install a double vanity drain plumbing?

Start off by making holes in your sink table if you have to. Then assemble most of the parts into a single pipe. That way you’ll be able to directly set it up. Remove the shelf and attach the assembled pipes to the main drain and the sink. Finally, connect the other sink.

This brief description is nothing compared to the detailed information that you will learn along the way. Sounds interesting? Read along!

Installing The Double Vanity Drain Plumbing in 3 Simple Steps

The thing is, you’re not going to have two drainage systems where there’s only one sink. You’ll have to call up a plumber and install another drainage system. Unless you install a double vanity drain plumbing by yourself. 

It’s okay, don’t worry because we have provided a step-by-step installation process just for you. Follow every step thoroughly and you won’t face any problem at all.

Necessary Equipment

Before we get into the steps, make sure you’ve got everything you need. Here are the tolls you’d need-

  • 2¼ inch Drill
  • One Rubber Flexible Couple
  • Two PVC 90 degree Street Flange
  • One PVC Tee Pipe
  • One PVC 45 degree Street Flange
  • Two 1¼ inch Marble Connector
  • Two P Traps
  • Straight Pipes (two or one; depends on you)

Now that you have all the equipment that you’ll need, let’s install the double vanity drain pump-

Step 1 of 3: Drilling The Sink Table Wall (Optional)

The first thing you have to do is drill the sink wall, but that’s optional. We’re saying that this is optional because not everyone would need this step. You’ll require this only if the sink table has walls between each sink. 

Remove the cabinet doors first. It’ll make your work much easier. It could be old and door hinges might become faulty. Just to be safe, learn to adjust old cabinet door hinges.

If there’s only one wall, just level the two pipes properly. But, if there are two walls, then you’ll have to be slightly sly. The wall close to the drain will be slightly lower than the other one. This will ensure that you get a smooth flow of water.

You’ll most likely have to cut the pipe that comes down of the new sink. This is to ensure that everything is at a level. 

Step 2 of 3: Assembling The Pipes

Let’s begin to assemble the pipes now. You’ll assemble some of the parts beforehand so that it’s easier to put them on.

The lower end of the Tee pipe will connect to the drain line. The upper end will connect to the second sink. And the center end will connect to the first sink.

In case you’re not sure which Tee pipe to get, here’s a list of some of the best ones-

Product 1
Product 2

Fit the two 90 degrees street flanges on the upper and lower end of the Tee pipe. On the lower end, fit the flexible coupling. It depends on you which type of flexible coupling you want to use.

On the upper end, connect the 45-degree street flange. Then, attach the straight pipe to the 45-degree street flange. And connect one of the marble connectors at the end.

Now attach the other marble connector to the center end. 

Most of the pipes have now been assembled. Let’s start setting them up now. 

Step 3 of 3: Setting Up The Pipes

If there’s a shelf, take that out first. Now, attach one of the P traps on the drain of the first sink. Then, take the assembled pipe and put it in place. Be sure to look out for leaks in the sink while you’re at it.

Tighten the P traps on the center end of the Tee pipe. Attach the lower end of the Tee pipe to the main drain. Make sure you tighten the hose clamps on the marble connectors. 

Let’s go to the other sink now. Attach the P trap on the drain of the sink. At the end of the P trap, connect the other 90-degree street Flange. 

Now, connect this street flange to the straight pipe. If your sinks are far apart from each other, then one straight pipe won’t do. Attach another straight pipe in between them. You can use a snappy trap instead of using another PVC pipe as they’re more flexible.

That’s just about it. You’re done installing the double vanity drain plumb. Check for low water pressure in your sink once you’re done.


Question: Will a double vanity add value to my home?

Answer: Yes, a double vanity makes your home more desirable. It also makes your house more attractive. It attracts potential buyers. If you ever plan on selling your house, a double vanity will help.

Question: How long is a double vanity usually?

Answer: They’re usually around 60-70 inches. But then again it also depends on the amount of space you need on the countertop.

Question: Which is better, a single vanity or a double vanity?

Answer: A single vanity has more countertop space. And a double vanity can fit in a whole extra person. You know which one you need more.


Well, this is everything you need to know about installing a double vanity drain plumb. You shouldn’t face any problem fitting them by yourself. Just make sure to follow our instructions the right way.

If you still face any issues, feel free to call a plumber.

Good Luck!