If the contractor made provisions for adding a bathroom in the basement during the construction of your home, you'll find plumbing stub-outs in the floor of the basement that will accommodate a shower, sink or commode. In a home where the main drain is above the basement floor level, or in a basement without drainage provisions, you can still add a shower. You'll need to install an up-flush system, however, to pump the water from the shower into your home's main drain.
Existing Plumbing Stub-Outs
The most efficient, and least expensive, method of installing a basement shower, without the need to break concrete, is to install it over existing plumbing stub-outs. This limits your ability to change the basement layout, but if the stub-outs are in place, using them will save money and labor.
Up-Flush Drainage System
An up-flush drainage system features a pump that removes sewage from a holding tank located behind a toilet, tub or shower and pumps it into the home's main drain (which ties into the line leading to the city sewer main) located at a higher elevation. The system also contains a grinder that liquefies solid waste for easy removal. The collection tank may be integrated into a special toilet, or you can install a tank behind a bathroom wall to keep it out of sight. You'll need access to an electrical outlet to run the pump, and the system must connect to the main drain and to the home's plumbing vent system.
To allow adequate drainage from the shower to an up-flush system, the shower must be elevated. The standard slope required on a water drainage pipe is 1/4 inch per linear foot of pipe. Creating room for the drain slope, as well as for a P-trap installed in the drain line beneath the shower, necessitates using an elevated shower base. This will result in the need to step up about 6 inches to enter the shower stall. You can purchase an elevated shower base or frame one from treated lumber.
Basement ceilings are typically lower than other ceilings in the house, and when you add an elevated shower, you'll further reduce headroom in the shower stall. Consider the location when installing a basement shower that will depend on an up-flush system. Generally, it's better to keep plumbing fixtures in close proximity. The farther away the shower is from the collection tank, the higher the floor of the shower must be to allow for adequate drainage.