Plumbing

[jeffbirdwell]

I have just removed my single sink vanity from my bathroom.  I replaced it with a double sink vanity.  I have water connections and drain for one sink rather than two seperate drains and waters connections for each sink.  Are there shut off valves that allow for two water supply connections.  Can I plumb the drains like the kitchen sink is plumbed.  The main thing I want to avoid is having to run another drain and water supply.

Please Help! we are tired of brushing our teeth at the kitchen sink!!

[Chris_HD_CHI]

Hello jeffbirdwell.  Welcome to the Home Depot Community!

It’s quite common for there to be only 1 line each in a bathroom for the drain, cold and hot water.  Yes, the drain can be plumbed like a double kitchen sink by converting the 1.25” sink flanges to a 1.5” and using a Tee below one of the bowls to join them.  There are also 1.25" flanged 90 elbows (shown below) that provide another way to accomplish this.  The “P-Trap” will be placed below the pipes that join the bowls.  How you actually design this will depend on where the wall drain is relative to the bowls.  Any Home Depot plumbing associate can help you with this given a simple drawing of the bowl spread, and location of the wall drain.

For the water supply, you can either use a Tee with 2 valves for each supply, or a simple double outlet valve like this:

I hope this helps.

Newf

[davidwh]

The problem with using one drain line for the double sink replacement is always blockage of drain lines from vanity drawers, and each vanity is different. 

I have been successful with several ubgrades by simply removing the drawers, plumbing the drains then shortening the drawers needed to let the drains pass behind.

Often only one drawer needs to be shortened. The process is to cut the back off straight with a table saw and then just replace the back of the drawer.

Sorry I am so lazy, but no issues so far.

[Chris_HD_CHI]

Hello davidwh.  Welcome to the Community!

I agree that there are times when drawers get in the way.  In addition, the place allocated in the cabinet design for the wall drain may not be where the wall drain actually is.  Vanities do vary in design.

It will always be easier to modify the vanity cabinet to accommodate plumbing than to tear up the wall and move the outlet or add another one.  I like your process for shortening drawers.  It seems quick and easy.

Thanks for the tip,

Newf.

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[mac517]

Newf-

I read a 2010 reply you posted for a user interested in installing a double sink for a bathroom vanity where currently only one existed.  I am doing the same thing and found your post helpful. Two follow up questions:  1)  does the second plumbing connection which will be connected to the first need to be vented or is the vent from the existing connection sufficient?  2)  If I understand your previous answer, the new sink flange will also have a P trap that empties into  the horizontal PVC pipe connecting to the Tee elbow.  Is this correct?

mac517

[Chris_HD_CHI]

Hello mac517.  Welcome to the Community!

Normally the venting for sinks is a vertical pipe inside the wall which leads from the drain up to the roof.  It is not necessary for each basin to have its own vent, as you will tie both basins to that same wall drain.  Only if you are starting with a stud wall and using separate wall drains will you need both to be vented.  Even then you would simply tie the vents together at some level higher than the sink tops.

How you do that depends on what is the easiest way given vanity layout, drawers and spacing between the basins.  You can either tie the basins together before a single P trap like is often done with double kitchen sinks, or have each basin get its own trap and run their horizontals into a Tee or Wye fitting at the common wall drain.  In addition, some installations would use a double Wye where the extra hub has a cleanout plug.

Is this what you are looking for?

Newf.

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