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How Do You Rough In A Double Sink Vanity?

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

Double sink vanities are regal, striking and completely practical, you’ve most likely seen them or even grew up in a household that boasted them.

If not, in simple terms a double sink vanity is a vanity with two sinks instead of the regular one, they’re useful if you have multiple people in the household, as it allows the freedom and space for two people to get ready each morning without the stress.

In short, you get two sinks for the same price as one. You may be wondering that if there’s two sinks then there will be two sets of plumbing needs too, but that’s not necessarily the case.

In most situations supply and drain pipes can accommodate two sinks and all you’ll need is tee fittings, hoses, 90 degree elbows, extension pipes and special valves.

Before starting this task, as with all plumbing jobs you should consult the local plumbing regulations and have a quick chat about your plans with the local plumbing inspector. 

This article will outline the process of how to rough in a double sink vanity within your home and some tips and tricks regarding it. So let’s get started. 

What Is Rough In Plumbing?

A plumbing rough in refers to making holes in the framing studs and flooring, which is where the water supply and drain pipes will run.

Then all the pipe connections are made either to feed into or take from the plumbing fixture. 

So what does the rough in part actually mean? Well, the “rough” part refers to the pipe’s dead end being in the lower part of the wall, more specifically behind the vanity cabinet doors.

No sink or faucet has been attached to them yet, so they are technically unfinished.

Everything to do with the plumbing will be behind those vanity cabinet doors, the exact same as a single sink’s plumbing is enclosed beneath the sink.

As the double vanity is large enough for two sinks, as too are they large enough to encase all the plumbing needed.

Some Points To Consider Regarding Double Sink Vanities and Plumbing

If you’re going to install double sinks, they should be spaced at least 30 inches apart but if possible, 36 inches is a lot better.

Remember, you’ll most likely be standing in there with another person, you’’ll want enough elbow room when you’re brushing your teeth.

Along with giving both of the people in there enough space, this also allows plenty of space beneath the sink for the plumbing needed to feed water to and drain it from both sinks too. 

What Materials Should You Use?

Materials for bathroom sinks are in abundance and there will most likely be at least one to your style.

A double sink configuration will often come as a single vanity top, which 

eliminates the need to measure the spacing between the sinks. 

Some popular materials used for bathroom sinks include:

  • Ceramic is by far the most popular used for bathroom sinks because it is durable, easy to clean and blends well with most bathroom interiors.
  • Stainless steel is a little boring by comparison to all these materials, but it is an eco-friendly option, it’s cheaper than most other materials and germ-resistant.
  • Porcelain whilst it belongs in the same family as ceramic, it is significantly tougher. It’s soft in appearance whilst also remaining easy to clean. 
  • Teak wood is often the most common wood material used for bathroom sinks as it is highly resistant to mildew and brings a natural and warm interior atmosphere to the bathroom. You shouldn’t ever clean this type of sink with a scourer, use a soft pad when cleaning. 
  • Bronze elevates a bathroom’s interior appearance because of how unique it is whilst also remaining durable. It is highly resistant to corrosion and has antimicrobial qualities.
  • Natural stone sinks such as onyx or marble are characterized by unique quirks and differences that make each natural stone sink completely unique. They are very low maintenance and easy to clean and are very adaptable and customizable because they are all handcrafted. 

Whatever material you decide to use will make your bathroom stand out and make a statement due its uniqueness and classy fixtures. 

Plumbing Needs

Each sink will have a drain line that carries out the waste water, and the pipe has to have a trap to seal the drain.

The seal is needed to prevent sewer gasses from getting to the bathroom.

As well as this, every sink needs a sink vent so that it can function correctly.

How Do You Rough In A Double Sink Vanity (1)

A vent will help to equalize the pressure on the drain pipe as the water flows down to ensure that the water flows smoothly. 

Some Handy Plumbing Instructions 

As with most things nowadays, there’s usually a youtube video or two to go into more detail regarding the process, and to visually show you everything to do.

We recommend that you watch a few so that you’re comfortable with the process and can do it with ease. 


Regardless of the amount of people within your household (unless you’re living alone) it is always convenient to have the extra space and so there’s no arguments about who’s been in the bathroom for too long. 

The extra space and the regalness of it is an added bonus, but what if we told you that it would increase the value of your house too?

Most household bathrooms will have a single sink vanity, so if yours has a double sink vanity it’ll definitely look more attractive to potential buyers if you ever decide to sell. 

There’s not really many cons to a double sink vanity, except for the fact that the sinks take up quite a lot of space so you won’t be able to place a lot of things on there unless they’re small.

But you would have the same problem with a single sink vanity, and there is always an option to opt for a larger width cabinet.

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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