All You Need to Know About Adding a Basement Bathroom
Adding a basement bathroom can be a plumbing challenge, but remodelers have options for underground plumbing.
Adding a basement bathroom adds value to the home, but installing toilets and sinks in a belowgrade environment takes more than a basic knowledge of drainpipes and sewer lines. Transporting waste to the sewer run is challenging because the gravity assist that works for upstairs waste removal will work against waste flow belowgrade. Fortunately there are a number of options that fall into the DIY category. New plumbing must meet code requirements, however, so do some homework and consider a master plumber for final connections.
Belowground Water and Waste Pipes
For some homes, moving belowgrade bathroom waste to the sewer, septic, or sanitation line is not a challenge because their lines are deep enough for add-on fixtures to benefit from gravity-assisted disposal. A call to the public works department will determine general sewer-line depth. Information specific to a home’s septic lines should be readily available to the homeowner. Consult a plumber or plumbing contractor to determine flow rates and whether the system can effectively remove waste from basement fixtures. If waste water drains by gravity into municipal sewer lines, install a backwater valve to prevent sewage backup in the basement. A backwater valve may require a permit, so check with your local building department and consult a plumbing contractor before you begin.
Transporting bathroom or basement wastewater to sewer or septic lines can be achieved in a number of ways. Aboveground solutions include the “upflushing toilet,” freestanding sewage-ejector systems, and composting toilets. Aboveground solutions are those that do not require the homeowner or installer to cut through any existing basement slab, resulting in lower installation costs. Upflushing toilets vary in look and operation, but generally include a pumping mechanism hidden within or behind the toilet. Some upflushing toilets permit additional waste-producing fixtures, like sinks and shower units, to drain into them.
Upflushing toilet systems are expensive, but money is saved on installation costs. “Upflushing toilets sit on top of the floor, you don’t have to break the concrete, and servicing them is easy,” says Larry Sturm, a master plumber in Pennsylvania and owner of Sturm Plumbing, the Faucet Doctor plumbing supply store, and UpFlushToilet.com, an online retail store. “Tie-ins take about a half hour, and recovering accidentally flushed items is pretty easy.”
Macerating and Composting Toilets
Some upflushing toilet systems include a macerating or grinding feature that reduces waste into smaller pieces prior to pumping, eliminating clogging issues. The Saniplus macerating toilet from Saniflo is an upflushing toilet system with a toilet bowl, toilet tank, and macerating unit. The macerating unit (which also houses an electrically powered motor and pump) can be placed in the bathroom or behind the wall, and is capable of pumping waste twelve feet vertically and/or 150 feet horizontally. The Saniplus allows for accompanying sink and bath/shower graywater discharge as well, costs around $900, and is easily installed and serviced.
Composting toilets are also viable solutions for belowgrade situations, but they are meant strictly for toilet waste. Composting toilets require little or no water, and must be vented to the outside for the composting process to work. The MS10 Composting Toilet from Envirolet runs on electricity, is self-contained, rests on the floor, and uses heat and a dual-fan system to evaporate liquids. These environmentally friendly toilets reduce water waste, and do not use chemicals for the composting process. There is a limit to how much material can be composted in a day, so use must be monitored and the unit must be emptied. Composting toilets can cost over $1,000.
The freestanding or aboveground sewage-ejector system is another waste removal option that does not require cutting through concrete. These systems are typically housed within an enclosure, and the toilet (usually not included) sits on top. These systems are essentially mini septic tanks. The toilet, sink, shower/bath, and washing machine can drain into these holding tanks, which also house the pump to discharge the waste up and into the home’s drainage lines. Because sewage-ejector units sit aboveground, fixtures like toilets and showers or baths will have to be elevated about six inches to gravity-drain into the tank. The Up Jon system from Zoeller sells for around $600, but does not include a toilet. Saniflo also sells similar graywater and sewage-ejection systems designed specifically for bathtubs, showers, laundry units, and kitchen sinks.
Belowground sewage-ejector systems are the least expensive option, but are complicated to install. These tank-and-pump units are designed to sit in a hole in the basement floor, allowing floor fixtures to gravity-drain into the tank. These units vary in size, but are typically twenty inches in diameter and thirty inches in depth. The holding-tank capacity generally ranges from thirty to forty gallons. “The nice thing about these systems is that they come as a package,” adds Sturm. “It used to be that you’d have to buy the parts separately and put it together. Now you can pretty much drop it in the ground and tie it in.” Homeowners should expect to pay around $400 for a belowground system. The true cost, however, is in the installation. Cutting through a concrete slab to dig the hole for the unit, as well as any drainage pipes from additional basement fixtures, will set the homeowner back a pretty penny. ”It can easily cost thousands of dollars to install,” says Sturm. “And if you flush something down the toilet by accident, recovering it can be a very messy job.”