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Vanities for Small Bathrooms

Updated sinks and faucets add a modern look to any bathroom. My prior post shared how we replaced my sister’s 1970s vanity cabinet with a new one from Allen and Roth.

Installing the faucet and sink took us less time than we thought. Primarily because new faucet technology makes faucet replacement a lot easier than it used to be, compared to even just 3 years ago.

After reading this tutorial you should be able to do this project in less 1 hour. If anything, it probably will take you longer to remove the old faucet if you’re not removing the sink.

Here’s a list of tools & supplies you’ll need for this project:

  • Channel Locks
  • P-Trap Assembly
  • Tailpiece Extension Tube
  • Caulk
  • Caulking Gun
  • Teflon Tape
  • Hack Saw
  • Miter Box (optional)
  • Crescent Wrench
Let’s get started!!


Step 1: Add the Faucet to the Sink

One big recommendation I have is to use name brand faucets. Having several rental properties has taught me to do this because if the faucet breaks you can easily get replacement parts.

American Standard faucets have been a good choice for me in the past and my sister chose one for her bathroom.

The water should be shutoff to the old faucet by turning the shutoff valves completely to the right.

Rest the new bathroom sink on the floor and insert your new faucet into it.

Insert the faucet into the sink

Place the black mounting nuts that came with the faucet onto the faucet tailpieces. Tighten the nuts until the faucet is snug against the sink.

Place the black mounting nuts on the faucet tailpiece

Insert the drain that came with the faucet into the sink. Ensure the slot for the stopper faces the back of the sink. Then slide the rubber sealing gasket up the drain so that it sits against the sink.

Insert the drain into the sink

Make sure the tabs in the stopper slot are in the correct position. Our American Standard faucet required the tabs to be at 1 o’clock and 7 o’clock. This is SUPER important and will enable your pop-up stopper to properly go up and down.

Make sure the tabs in the stopper slot are in the correct position

Insert the plastic washer that came with the faucet drain against the rubber sealing gasket.

Place the plastic washer against the rubber sealing gasket

Slide the plastic locknut up the drain and tighten it with channel locks. If there’s going to be a water leak it will be in between the rubber gasket and sink. The plastic locknut pressing the gasket against the sink is what stops water leaks.

Slide the plastic locknut up the drain and tighten it with channel locks

Attach the pop-up stopper assembly to the stopper slot and tighten it by turning it to the right. This is one of the best parts of new sinks. The pop-up stopper assembly is now super easy and doesn’t require any fiddling around with nuts, clips, linkage, etc.

Attach the pop-up stopper assembly to the stopper slot

Test the pop-up stopper to make sure it goes up and down. If it doesn’t unfasten the stopper assembly from the stopper slot and make sure the tabs in the slot are in the correct position.

Honestly, this happened to me but it didn’t take much time to fix.

With the sink still on the floor I highly recommend fastening the steel braided water supply lines to the faucet. I never use any other type of supply line and if your shutoff valves are in bad shape this is a good time to replace them, too.

Fasten steel braided water supply lines to your faucet tailpieces

At this point you can pick up your sink and place it on your bathroom vanity cabinet.

Step 2: Assemble the P-Trap to the Bathroom Faucet

This is perhaps the most frustrating part of putting together vanities in small bathrooms. Primarily because there are so many places for water to leak.

The P-Trap consists of numerous slip nuts that always like to give me headaches.

Here in the states bathroom plumbing for P-Traps is usually 1 1/4 inches in diameter. The faucet and sink manufactures never provide P-Trap parts.

So if you want to replace them you’ll need to buy a kit that looks like this (this is the diagram on the back of the bag).

Buy a P-Trap kit for the new sink

Here’s a tip you need to know: purchase a tailpiece extension tube. This tube fits on the drain tailpiece and extends it downward. I can’t tell you how many times I’ve needed this. Now that I think about it, I’ve needed on every sink I’ve installed.

You can find it in the same section as the P-Trap kit.

Begin the P-Trap assembly by attaching a slip nut on the tailpiece followed by the slip nut washer. Make sure the washer’s tapered end faces downward.

Place a slip nut and slip nut washer on the drain tailpiece

Put the J-Bend and wall tube together. Place the the wall tube in the wall stub-out. Make sure the wall tube goes into the stub-out as much as it can to ensure there won’t be a water leak.

Check to make sure the drain tailpiece will go down into the J-bend by at least 1 inch.

Assemble the wall tube and J-bend

If you need to trim the drain tailpiece use a hacksaw and miter box to make a clean cut. Make sure the cut edge is smooth because any loose plastic fillings will cause the fitting to fail.

You could also buy a plastic pipe cutter. This tool is fantastic and as a result I’m never using a hacksaw again to cut P-Trap parts 🙂

Use a hacksaw or plastic tube cutter to trim P-Trap tailpieces

With the P-Trap in place tighten all the slip nuts except for the one that connects the J-Bend to the tailpiece or extension tailpiece.

Tighten all the slip nuts except the one that connects the J-bend to the tailpiece

Step 3: Securing the Sink to the Vanity Cabinet

Lift the sink off the vanity cabinet and apply a bead of silicone caulk along the cabinet top perimeter.

Apply a bead of caulk to the top perimeter of the vanity cabinet

Set the sink back onto the top of the vanity cabinet and tighten the slip nut that holds the J-bend & drain tailpiece together.

Hand tighten the water supply lines to the shutoff valves. Use a crescent wrench to turn the supply line nut 1/4 to 1/2 turn to the right.

Fasten the water supply lines to the shutoff valve

Remove the strainer from your faucet before running the water to prevent debris from clogging it. This is especially important if you’ve been doing extensive remodeling in your bathroom.

Remove the strainer from your faucet before running the water

Turn on the water to the faucet and check to make sure there are no leaks coming from

  • the hot water supply line at the faucet  tailpiece and shutoff valve
  • the cold water supply line at the faucet tailpiece and shutoff valve
  • the rubber gasket on the underside of the sink
  • the slip nuts in the P-Trap
  • the stub-out at the wall

If you encounter leaks at the supply line fittings tighten them 1/4 turn with a wrench.

If you encounter leaks at the slip nuts place a bucket under the P-Trap. Then undo the slip nut and make sure the P-trap fittings are sitting flush before re-tightening them. You can also put teflon tape on the threaded ends of the P-trap pipes.

Finished bathroom sink faucet

Here are the Summary Points for this tutorial

  • Turn the water off at the sink faucet shutoff valves
  • Insert the new faucet into the new sink
  • Place the black mounting nuts on the faucet tailpieces
  • Tighten the mounting nuts until the faucet is snug against the sink
  • Insert the drain into the sink
  • Slide the rubber bushing up the drain
  • Make sure the tabs for the stopper slot are in the correct position
  • Place the plastic washer against the rubber sealing gasket
  • Slide the plastic locknut up the drain and tighten it with channel locks
  • Attach the stopper assembly to the stopper slot and test
  • Fasten the steel braided water supply lines to the faucet tailpiece with channel locks
  • Assemble the P-Trap to the sink drain
  • Tighten all the slip nuts on the P-trap except for the one that connects the J-Bend to the tailpiece
  • Apply a bead of caulk on the vanity cabinet top perimeter then set the sink back in place
  • Tighten the P-trap slip nut between the J-Bend and tailpiece
  • Take the strainer off your faucet before running the water
  • Turn on the water and check for leaks


What’s Next 

If you’re doing a bathroom remodel and need help, join one of our online courses – they’ll make your bathroom renovation much easier!

Let me know if you have any questions and I’ll do my best to help.



Vanities for Small Bathrooms

  1. SheilaG @ Plum Doodles says:

    Thanks, Jeff- this will come in really handy. Pinning it so I can find it easily! 🙂

    1. Jeff says:

      I’m really happy to help you any time Sheila 🙂

      Let me know if you ever have any questions.

      Thanks for the pin!!

  2. Connie Lichtenberg says:

    I am considering refinishing or painting our current bathroom vanity. It’s a light wood whereas the floor & sink are a black & white marble. Would there be any additional prep if I wanted to simply remove the vanity for refinishing and then reinstalling the same sink/vanity once the refinishing is complete? I don’t want to ruin the vanity getting it off the wall. However I don’t want to ruin the floor of sink by refinishing it in place. Any help would be appreciated as the updates we’d like to make to our new 20 year old home are numerous. Having put most of our money toward the purchase makes replacing everything with brand new cost prohibitive.

    1. Connie, I totally know where you’re coming from. You described our first house to a T. Removing the vanity shouldn’t be too hard. It’s probably attached to the studs with a few screws. Simply remove the screws and pull the vanity away from the wall. But make sure the previous owners didn’t caulk both the sink and vanity to the wall itself.

      If they did, just go ahead and score the caulk with a utility knife then remove everything. Before painting the cabinet sand it down with 220 grit sandpaper, remove excess dust with a sponge, let it dry then prime it. You can then add Floetrol to your topcoat of paint to get a great looking finish.

      Hope this helps you get started 🙂


  3. Susan says:

    Hi Jeff,

    First off…love your blog! Second, I own a home that has numerous poorly executed renovation projects. The latest of the headaches is the leak under the bathroom sink. It’s coming from the area where the tailpiece meets the drain pipe. I’ve tightened the slip nut to the max but since the tailpiece is significantly smaller than the drain pipe, I don’t really see the slip nut doing much of anything. So my questions are: Am I not suppose to have tailpieces that are smaller than the drain pipe? If not, how do I go about fixing this with the least headache? The sink mostly leaks when I wash my hand with soap and the soap suds/water gets pushed up and out between the gap of where the tailpiece meets the drain/slip nut.

    Thank you for your help in advance.


    1. Susan, I’ve experienced this same issue. Complete frustration for sure.

      The tailpiece from your drain should be the same size as the P-Trap. Typically the sizes are 1 1/4 inch or 1 1/2 inch in diameter. And the bathroom pipes are 1 1/4 inches. Thus, what you can do is buy a longer tailpiece or extension tailpiece at the store. Here’s what you should do:

      1. Remove the existing tailpiece with channel lock pliers
      2. Take the tailpiece to the store
      3. Go to the plumbing section
      4. Find a 6 inch or 12 inch extension tube that is the same diameter as your original piece and buy two extra slip nuts & washers for that pipe diameter
      5. Stop at checkout and pay, also buy a Snickers if possible (this part is optional but always satisfying)
      6. Once home, place the new extension piece next to the drain tailpiece and place a mark on the bottom such that it goes into the P-Trap at least 1 1/2 to 2 inches
      7. Trim the new tailpiece
      8. Install the tailpiece using the slip nuts and washers that are on the P-Trap and drain tailpiece
      9. Run the water and check for leaks, if there is a leak make sure the slip nuts are tightened 1/4 turn

      Hope this helps and please let me know if you have any questions 🙂


  4. Rick says:

    Jeff: I interpreted Susan’s question above to be similar to my problem.

    She said: ” Am I not suppose to have tailpieces that are smaller than the drain pipe?”

    I thought she was talking about diameters and I think you were addressing lengths.

    In any event in my case the tailpiece (1 1/4″) is smaller diameter than the P trap (1 1/2″) and the 1 1/4 ” adapter/gasket for the 1 1/2″ nut connected to the P trap doesn’t cinch down on the tailpiece tightly therefore allowing leakage. The remainder of the drain leading through the wall is 1 1/2″.

    It would seem the solution would be to use a P trap designed to receive a 1 1/4″ tailpiece and exit at 1 1/2″ but I didn’t see any at Home Depot. Is this the right track and are these available?

    suggestions appreciated and thanks in advance,

    1. Hi Rick,

      You can buy a reducing washer that will allow the 1 1/4 inch to be compressed tightly against the 1 1/2 inch pipe. You can also but a P-Trap with one end being 1 1/4 to accommodate the tailpiece (1 1/4 inch in diameter) and the other being 1 1/2 inch to fit snug with the wall drain.

      And if you can’t find these parts at the local hardware store any good pluming supply house will have them.

      Hope this helps 🙂

  5. Mike Kohm says:

    Just followed your directions, installing a new faucet into a old sink. That went fine. But upon replacing the p-trap plumbing there is more tension in the system and this pushes the setting of the sink away from the wall. So much so the sink will no longer sit flush with the wall. The sink and counter top are one piece.

    It looks like the new drain pipe is slightly longer than the old one, so cut off 3/8″ of the tube that fits onto the drain pipe. That slightly helped but did not address the tension in the system. Not sure what happened. We did take the p-trap apart to make the plumbing easier.

    Tried to adjust the p trap plumbing several different ways, but did not get the tension out of the p-trap line. Same vanity, same counter top?

    Any ideas would be greatly appreciated.


    1. I’ve had this happen before Mike.

      No fun, for sure.

      It sounds like the goose neck (tube that goes into the wall) make not be the entire way in the wall pipe. Did you make sure it’s pushed in to accommodate the location of the p-trap?

      Feel free to take a few pics and send them to me. I’ll send you a personal email.

      We’ll figure this out together. Two minds are better than one, right? LOL.

  6. Marylou Johnson says:

    Hi Jeff! I just found your website by following a link in Hometalk. I am so glad to have found this particular tutorial, and can’t wait to use it. BUT, I have an additional challenge…I live in a mobile home, and the water lines under my sink DO NOT have shut-off valves! Could you please address this problem in a tutorial to show which pieces are needed to be bought and how to install them? Any help you can give would be greatly appreciated! Thanks!

    1. Thanks so much Marylou, if you have the ability to turn off your main water supply you could cut the water lines and add shutoffs. One easy fix is to use either shutoffs with compression fittings or SharbBite push on shutoffs.

      To make things easier on you you could take a picture of the supply lines from the sink so that you know what size shutoff to get. If you have any questions I’d be happy to help.

  7. melissa says:

    thanks so much- the p-trap info was very helpful. i had ran into some problems when i was installing the new faucet/disposal on my new sink. come to find out the parts in my p-trap were not right- the clear rings. wrong size. after staying up til midnight trying to figure that thing out- i called it a night. woke up at 6am and searched the internet and found your tutorial. got it all squared away! thx

    1. Fantastic job Melissa. I know that feeling of frustration, it’s no fun.

      The washers can be big pain if not the right size. I’m happy you figured it out 😀

  8. Hi! Thank you for your info. I am trying to get someone to connect my vanity, and I’m trying to buy a P-trap at Ace Hardware. My vanity is small, and my bathroom is small. Do you have any idea which of the following P-traps I should buy: (1) Charlotte 1-1/2in P-Trap w/Clean Out; (2) Charlotte 1-1/2in P-Trap; or (3) Charlotte 1-1/2in Adjustable P-Trap w/Chrome Nut. I appreciate your help. Thank you.

  9. Jeff Spencer says:

    The black mounting nuts are to large to use with my sink, I need a typical nut that I would use a wrench to tighten.
    Where can I find the right size nut, my Ace hardware does not have it.

  10. Patricia says:

    Can you give suggestions for attaching a smaller diameter pipe 1 1/4″to a larger wall outlet pipe that does not protrude?

    1. Patricia says:

      This would be under the bathroom sink.

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