How to Finish a Basement Bathroom

By |Last updated on |Basement, Bathroom, Plumbing|27 Comments

How to finish a Basement Bathroom project series for the Do-It-Yourself handyman or homeowner. Links to each construction phase are summarized below, beginning with the bare walls to the finished bathroom, with cost of materials and total days of labor to complete the job.

The toilet, shower and sink empty into a sewage basin set in the concrete slab floor. A sewage ejector pump lifts the effluent overhead to drain into the main sewer line.

Basement Bathroom Finishing Cost

Finished Basement Bathroom: Vanity, Toilet and Shower

Finished Basement Bathroom: Vanity, Toilet and Shower

I did all of the labor working mostly weekends with occasional help from my teenage son. Total labor for this project was about 8 to 10 man-days; I emphasize quality and neatness when working so I may be a little slower than others. Setting the tile is by far the most labor intensive part of the project.

The total material cost to finish the basement bathroom was about $5,600 as follows:

  • $1700 porcelain tile, grout and thinset mortar
  • $500 shower stall bedding cement, metal lathe, shower pan liner, cement backer board, screws, glue, etc.
  • $1000 vanity cabinet, sink, faucet, vanity mirror
  • $600 for copper- and PVC pipe and fittings
  • $100 shower valve
  • $550 sewage pump and high water alarm
  • $150 exhaust fan
  • $200 electrical wiring, junction boxes and misc.
  • $30 building permit
  • $100 2×4 boards and plywood sheeting
  • $350 toilet and fittings
  • $150 towel racks, toilet paper holder
  • $75 paint
  • $100 tile wet saw rental

I already had all the tools necessary for the project except for the tile saw which I rented from Home Depot.

How to Finish a Basement Bathroom

This is a big project described in the following phases:

  1. Part 1 – Project overview, rough-in plumbing connections, painting the walls.
  2. Part 2 – Floor plan and fixture layout, relocate the shower drain in the concrete slab floor.
  3. Part 3 – Build the tile shower stall and shower floor.
  4. Part 4 – Tile measurements and layout.
  5. Part 5 – Tile the shower stall walls and floor.
  6. Part 6 – Solder shut-off valves on the sink and toilet copper water lines.
  7. Part 7 – Installing the shower head and valve. SharkBite solderless fittings.
  8. Part 8 – Hot and cold water copper plumbing connections to the main water lines.
  9. Part 9 – Sewage ejector pump installation and connect to the main sewer line.
  10. Part 10 – PVC sewer and outside air vent plumbing.
  11. Part 11 – High water alarm wiring and installation.
  12. Part 12 – Instal the toilet flange, setting the toilet, hooking up the water line.
  13. Part 13 – Bathroom vanity, sink, faucet, drain and water supply plumbing.
  14. Part 14 – Vanity light and switch electrical wiring and installation. Wiring diagram of the “before” and “after” branch circuits.
  15. Part 15 –  Wiring the light switch. Overview of the GFCI, exhaust fan and vanity light switches.
  16. Part 16 – Wire and install the vanity light.
  17. Part 17 – Bathroom exhaust fan installation overview.
  18. Part 18 – Sewage basin closure and testing for odors; overview of the water and sewer plumbing.

Finished Basement Bathroom Before and After Photos

In the beginning, the basement bathroom was bare walls and concrete slab floor with roughed-in plumbing stubs:

Finish a Basement Bathroom: Plumbing Rough-In

Finish a Basement Bathroom: Plumbing Rough-In

The bare walls and floor were transformed into an attractive basement bathroom:

Finished Basement Bathroom - Toilet and Shower

Finished Basement Bathroom – Toilet and Shower

Before – Hot and cold copper water pipes and PVC drain pipe plumbing rough-in for the toilet and vanity:

Finishing a Basement Bathroom: Plumbing Rough-In for Vanity and Toilet

Finishing a Basement Bathroom: Plumbing Rough-In for Vanity and Toilet

Finished basement bathroom toilet and vanity:

Finished Basement Bathroom - Toilet and Vanity

Finished Basement Bathroom – Toilet and Vanity

Basement bathroom vanity and light:

Finished Basement Bathroom Vanity

Finished Basement Bathroom Vanity

Another view of finished basement bathroom vanity, door and tile:

Finished Basement Bathroom Vanity

Finished Basement Bathroom Vanity

I hope you find this bathroom project series informative and saves you money by:

  • Helping you plan your Do-It-Yourself project.
  • Understand the scope of work if hiring a contractor and knowing if your getting quality results.

Finish the Basement Bedroom

After completing the basement bathroom, I converted a basement utility room into a nice bedroom in How to Finish a Basement Bedroom.

Thanks for reading,
Bob Jackson

Copyright © 2018   Reproduction strictly prohibited.


  1. moab March 10, 2009 at 2:55 pm - Reply

    Thank you. Top quality work which is hard to find.
    Excellent documentation which helped me learn a lot.

  2. TonyA October 26, 2009 at 4:30 pm - Reply

    Great series. I noticed you didn’t vent the bath sink. Is that not required?

    • Bob Jackson October 26, 2009 at 5:48 pm - Reply

      It’s a lengthy project and you missed this item.

      A plumbing vent is absolutely required for the bathroom sink. It’s required by my local building codes and the Building Inspector specifically checked it was installed before signing off on my permit. On a practical note, you need the vent to prevent the sink trap from getting siphoned dry and allowing sewer gases to enter the room.

      The Studor Vent installation is covered in Part 13 – see about midway down the page.

      Here’s the photos of the Studor Vent from Part 13:

      Studor Valve and PVC Drain Fittings

      Studor Valve and PVC Drain Fittings


      Fitting up the PVC Drain Plumbing

      Fitting up the PVC Drain Plumbing

      Bob Jackson

  3. Bob Jackson February 21, 2010 at 8:35 pm - Reply

    TonyA sent this e-mail update on his basement bathroom project:

    “Thanks again for your series on finishing a basement bath. You inspired me to take on a similar project on basically a framed and stubbed basement bath in the house we bought in 2007. I’m almost done. Funny thing happened today when I tapped into the vent rough in to the roof. As I lay in bed last night thinking through my plan to cut the stub and connect the vent up, it occurred to me that it probably had been collecting water since 2003 when the house was built. Surely the builder would not disappoint and ran a straight pipe pointing to the clear blue sky. So, I decided to drill a small hole right above the end cap on the stub. Although I had my bucket ready, I still got a nice little shower and had to yell for my wife to bring me a bigger bucket as the 5qt I was holding filled pretty fast.

    Anyway, thanks again for your series. It has been very helpful and I’ve referred to it often throughout my project.


    My e-mail reply to TonyA:

    “Hi Tony,
    I’m very pleased my web site was helpful to you!

    > it occurred to me that it probably had been collecting water
    > since 2003 when the house was built.

    Your builder did you a favor by capping the bottom of the vent pipe. My builder left the bottom end of the vent pipe open to the basement and the rain water would drip onto the 2×4 wall frame. I put a plastic bucket below the vent pipe and it would have maybe 1/4 inch of water whenever I checked.

    Thanks for the feedback,
    Bob Jackson

  4. f meyers May 16, 2010 at 10:28 am - Reply

    part 13 is hosed. missing much information, not complete. the page is not finished, only 1st page loads. no such before and after photos of the studor valve shown in the opening page of the series

    • Bob Jackson May 16, 2010 at 11:36 am - Reply

      Try the Part 13 link again, it’s working fine now. I was running a database backup and it might have interfered with the web page availability.

      Let me know if it’s working for you.

  5. BF Deeg February 27, 2011 at 6:10 pm - Reply

    Thank you for a very helpful instruction on how to add a bathroom and how to calculate the costs.

    Really appreciate it.

  6. Jill F. April 2, 2011 at 3:39 pm - Reply

    You have the best website I’ve ever come across. I’ve only been doing diy for a few years and love it, but I’m was so tired of trying to learn from the diynetwork. They’re so heavily edited that the part I’m often interested in learning is cut out. You give great step-by-step detailed instructions that are easy to follow. My husband is amazed that I was able to remodel our guest bathroom from the subfloor up. Sites like yours make that possible. Thanks! Jill

  7. Ted Klein October 23, 2011 at 10:39 am - Reply

    Great article and excellent documentation really well explained. Thanks

  8. Juma February 15, 2012 at 10:56 am - Reply

    Amazing! Really helpful. And very neat! Thanks I”ll follow it.

  9. james August 7, 2012 at 6:32 pm - Reply

    When the builder puts in a rough in for the toilet sink and shower are they all connected to the vent and will the shower have a trap put in that is in the concrete ? Thanks Much.

    • Bob Jackson August 8, 2012 at 8:36 am - Reply

      You must verify what the home builder has roughed-in. In my situation, the plumbing vent pipe to the roof is only connected to the sewage basin. I installed a Studor Mini-Vent for the bathroom sink.

      I’m guessing your builder cemented in the shower drain pipe and you’re trying to determine if there’s a p-trap under the concrete? Try shining a flashlight down the shower pipe; do you see standing water at the bottom or at least what appears to be a U-curve? If the pipe is dry, pour some water down the pipe to fill up the p-trap. You should see standing water in the trap that will rise and fall slightly with changes in air pressure.

  10. atisha November 20, 2012 at 2:27 pm - Reply

    Hi Bob
    Thank you so much for sharing this information. I wondered did you do the plumbing rough in work yourself? I see some DIY chatrooms say you can do this yourself but I would feel more confident having a plumber take care of that part.

    • Bob Jackson November 20, 2012 at 6:17 pm - Reply

      The home builder roughed-in the plumbing which runs under the cement floor or in the wall:
      * sewage basin
      * shower and toilet drain pipes
      * copper pipes inside wall for the toilet and sink

      I did everything else as illustrated in the project series, including the hooking up the bathroom to the main water supply and sewer pipes. I filed for a Building Permit and passed all inspections.

      If you’re not comfortable and knowledgeable in what is to be done, definitely hire a licensed plumber. Hopefully you’ll be in a more informed position having read about my basement bathroom project.

  11. Sunil February 3, 2013 at 9:34 am - Reply

    This is really one of the best articles I have seen! I’m preparing to build my basement bathroom and I learned quite a few things I didn’t know or think about – the basin alarm, the sink vent, SharkBite fittings and the use of the flexable sewage tee. I was really sweating the task of getting the tees into the water and sewage lines but your ideas solve that problem!!

    The only thing I’d like to point out for anyone else coming into this type of a project is that it may not be possible to add the plumbing and electrical after the close-in. In my case, all of it has to be done before drywall and tiling since I have no backside access.


  12. Eric Niermann February 27, 2015 at 8:54 am - Reply

    I just found your site on finishing a basement bathroom and it is better than anything I’ve been able to find to date. I’m starting my project in a month or so and feel much more confident now that I’ve found your site as a resource. Thanks in advance and I’ll let you know how it goes.


    • Bob Jackson February 27, 2015 at 6:09 pm - Reply

      I’m flattered and look forward to your update!

  13. Tina July 11, 2015 at 1:16 pm - Reply

    Oh no! I just pinned this page to my Pinterest board a few minutes ago. I’m glad that I scrolled down and read these comments. I’ll be sure to remove the pin from my board immediately.


    • Bob Jackson July 11, 2015 at 1:46 pm - Reply

      Hi Tina – I’ve since changed my mind about Pinterest and removed that old comment. Go ahead and pin.

  14. Don December 22, 2015 at 8:10 pm - Reply

    We had a bathroom plumbing roughed in but can’t figure out for the life of me what kind of layout I can do. Wish I’d payed more attention to it before the concrete was poured. Can I send a picture?

    • Bob Jackson December 23, 2015 at 1:08 pm - Reply

      Sure! Send photos to bob[at], replace the [at] with the @ symbol.

  15. debbie February 20, 2016 at 11:27 pm - Reply

    I what to change the basement shower into a bathroom sink and bowl with the shower drain how can I so that?

    • Bob Jackson February 21, 2016 at 12:06 pm - Reply

      That would be a major remodeling effort. The shower stall and pan would have to be torn out, rearrange the hot & cold water plumbing and cut the cement floor to relocate & change the shower drain pipe. If you have the floor space it’s probably easier to extend the shower plumbing connections to serve a bathroom sink. You didn’t say if there’s a toilet but that could be added if not present for a complete bathroom and add value to your home.

  16. Anthony Phillips May 20, 2016 at 9:54 am - Reply

    Hi Bob

    First off, thanks for the effort you put into setting up this site. Its unbelievably detailed and easy to search.

    I have a question. I am finishing off my basement bathroom – shower, toilet and pedestal sink. Do I need an exhaust fan to vent outside?

    1) I have a moisture resistant drywall in place.
    2) its a tiled (on handiebacker boards) shower and tiles on concrete floor.
    3) the shower will be rarely used.
    4) its a small space 5ft x10ft

    The ceiling of the bathroom space is not as easily accessible as your space to install an exhaust fan. Can I do without it? Is there an alternative? Will keep the door open after showering most times help?


  17. Stephanie J July 28, 2016 at 2:41 pm - Reply

    Hi Bob,

    We’re purchasing a house that currently has a basement bathroom already installed in which the plumbing for the toilet is in the concrete. There have been rumors about the town not allowing basement bathrooms any longer because of a few cases of back up issues. We would like to keep the bathroom and are wondering if there were any precautions we could take to minimize the risk of the toilet backing up. I’ve seen the upflow toilets and such but our plumbing is right into the concrete. Is there any type of backflow preventor or device we can install that you would recommend?

    • Bob Jackson July 29, 2016 at 6:19 pm - Reply

      First you need to determine the if the elevation of the new home (including the basement floor) is above or below the first upstream manhole on the public sewer. Does your home matches Building #1, #2 or #3 as illustrated on page 2 of the Sioux Chief Backwater Valve Installation Guide? Consult a license plumber if uncertain.

      Building #1 – all floors, including the basement, are above the first upstream manhole:
      If your home matches the diagram for Building #1 then you’re not at risk for a public sewer backup into the basement bathroom and a backwater valve is not required.

      Building #2 – basement floor is below and main floor is above the first upstream manhole:
      A backwater valve is required only for the basement sewer line. The main floor and above fixtures must not drain through the backwater valve. See the sewer connection diagram in the City of Santa Barbara Backwater Valve – Is One Required?.

      Building #3 – all floors of the home are below the first upstream manhole:
      A backwater valve is required on the home’s sewer connection to the public sewer.

      Backwater valves are required in the International Plumbing Code (ICC) per SECTION 715 BACKWATER VALVES. Most state and local governments Building/Plumbing Codes follow the ICC.

      If your home matches Building #2 or #3 and does not have a backwater valve it may be a Building Code violation depending on when the bathroom was installed. A licensed plumber can advise you. You’ll want to know before signing the home purchase contract.

      My home matches Building #3 because I live downhill from the first upstream manhole. My home has a backwater valve in the front yard to protect the entire house. A secondary backwater valve (a.k.a. check valve) is installed at the basement sewage basin discharge line as required by Code, but also to prevent backflow to the pump and for easier maintenance.

      Further information on backwater valves:
      * Plumbing Engineer – Understanding Backwater Valves.
      * Mainline Backwater Valve demo video. Mainline Mfg website.
      * Mainline Backwater Valve Installation video in the basement floor slab.


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