Basement Bathroom Remodel

Basement Bathrooms: What to Consider when Planning a Bathroom in the Basement

A bathroom in the basement, is a great addition to a home. The ability to send the kids down to play with facilities available has great resale value as well as contributes to the quality of life within the home. Whether the basement is used as an office, kid’s playroom, workshop or social gathering space, the presence of a bathroom is extremely handy and beneficial.

If you are fortunate to have a basement that exits out to grade, or has an easily accessed exterior door, the use of the basement bathroom from the outside will keep the remainder of the home cleaner and easier to maintain.

What considerations are pertinent to making a decision regarding the installation of a basement bathroom?

Access to plumbing

  • Sanitary line; this line is normally a 4” cast iron or PVC line, that if you are lucky extends out of the basement floor in a logical location. Many newer homes have rough plumbing already installed, in anticipation of a basement bathroom. The line, whether it is PVC or cast iron, is installed under the concrete slab on grade during construction. This is the easiest and most convenient situation.

If there is no sanitary line already installed in the basement floor, the following options are available.

  • If the primary sanitary line is low enough, this must be determined by locating the exit point of the sanitary line out of the home, the basement floor slab can be cut and removed, to allow the installation of a new basement sanitary line, to accommodate the new bathroom. This will be the exception. In most cases, if there is no sanitary line already installed in anticipation of a bathroom, the existing sanitary line exits the foundation too high, not allowing any positive drainage from the new bath location.

However, if you are one of the lucky ones, and the elevation of the existing line is low enough, then the excavation, installation of a new line is certainly a possibility.

  • If the primary sanitary line is too high to allow positive drainage, which will normally be the case, either a special toilet with a storage component and pump can be installed, or the more aesthetic option, the installation of a pump chamber, and what is called a trash pump installation.

The pump chamber and trash pump is a common installation requirement if the elevations of the primary line do not correspond to a positive drainage situation, or even if the location of the installed sanitary stub up ( which is the line installed in anticipation of the bathroom installation ) is not in a location that is conducive to where you want your bathroom to be located. Technology has sufficiently advanced that the installation of a chamber and pump is a common and convenient method of bathroom installation.


  • Water lines; the hot and cold water lines are normally not an issue. The location of the bathroom normally does not have a significant bearing on the installation of the hot and cold water lines. Todays convenient flex piping known as PEX tubing allows the plumber to run the water lines as required. The hot water line is normally run off of the primary hot domestic water service of the house; however, there could be circumstances that require the installation of a separate smaller hot water heater, specifically for the downstairs bathroom. Again, the installation of the hot and cold water lines is not a pertinent issue or problem, and takes a back seat to the location of the sanitary line.


The new bathroom will require ventilation from the space. Ventilation is accomplished by an exhaust fan normally installed within the ceiling of the new bathroom. The fan must be vented to the exterior of the home for the proper ventilation of the space. There are options for ventilation that distribute the air from the bathroom into the space between the first floor’s floor joists. This is NOT recommended, due to the quantity of moisture that will be incorporated in the vented air from the bathroom. If the air is simply distributed into the enclosed space, condensation will build up, and mold as well as deterioration of the framing material, flooring, etc. could occur.

It is always best to ventilate the bathroom directly via ductwork or wall vents to the exterior of the home. This is why the location of the bathroom, if possible is preferably on an exterior wall of the basement. This will allow direct exiting of the warm, moist air to the exterior.


The location of the bathroom in the basement is logically associated with the final intended layout of the basement. Is the basement going to be finished to provide additional bedroom space, an office environment or a social gathering place?   Will the bathroom be used for several different usages such as a common bathroom off a hallway, separate bathrooms for individual bedrooms, etc? The layout of the bathroom again is entirely based upon its intended use.

It is beneficial to understand that once, one bathroom is coordinated, meaning the sanitary line established, the installation of another is not out of the question. The biggest obstacle to the basement bathroom is the sanitary discharge, so once that is coordinated and solved, the addition of a second or even third bathroom will not present significant issues.

In terms of location, I prefer to locate any basement bathroom on an exterior wall, as I have already noted. This is for the convenience of ventilation, providing the opportunity for additional sound attenuation, as well as the possibility of a window installation. A window in a bathroom, especially when the bath is located on the basement level, provides a more open and spacious feeling within the bathroom.

Miscellaneous considerations

There are many other considerations that can be entertained when planning and coordinating a basement bathroom.

  • The installation of a janitors slop sink ( this is a low basin sink that can easily be a mop basin or a means of washing out miscellaneous cleaning containers )
  • The installation of a laundry sink, as well as a location for the washer and dryer.
  • Sauna installation, the basement is a perfect location for either a sauna or special steam room. Especially if the basement is finished to provide an exercise room or special work out facility.
  • Handicap requirements, if the basement is easily accessed by the exterior, is a consideration.
  • In – law set up that could accommodate a sick or ailing relative if the need arises.
  • Special accommodations for special showers and or soaking tubs.

The installation of a basement bathroom accentuates the resale value of the home, and also allows for creative and unique installations, that would not normally be installed on the upper floors of the home.

Technology as well as new materials and equipment, have almost solved all the issues that have caused individuals not to install bathroom in their basements. With the advent of flexible tubing, the issue of frozen pipes has all but gone away, and any issues with sanitary waste discharge have been solved with the advanced design of trash pumps and chambers.

Without knowing the specifics of your home and the installation of a bathroom in your basement, it is difficult for me to anticipate either problems or issues that would deter your decision not to further the investigation of installing a basement bathroom or bathrooms.

As I have indicated several times within this website, if still in doubt, the employment of a professional construction consultant, to review your specific issues, location and objectives, would be money well spent.

Hopefully you will be enjoying your new basement bathroom in the near future!



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