Basement bathroom additions in Idaho Falls
A second or third bathroom downstairs, planned around your drain line and the city's inspection schedule.
A basement bathroom addition puts a toilet, sink and shower or tub on the lower level of an Idaho Falls home, tied into the drain and vent system and inspected with the rest of the basement finish. It's for larger households sharing one upstairs bath, families adding basement bedrooms, and homeowners planning a guest suite. The outcome is a bathroom that drains properly, vents moisture outside and feels like part of the house.
Starting point: rough-in or not?
Many newer homes in Idaho Falls, Ammon and Iona were built with capped drains for a future basement bath. Using that rough-in keeps the job mostly to framing, fixtures and finishes. Without one, the slab has to be saw-cut and trenched to reach the main line, and if the main line is higher than the new fixtures, an ejector pit pumps waste up to it.
What's included
- Drain, vent and water lines, with rough-in plumbing inspected before walls close
- A shower, tub or prefabricated shower base
- An exhaust fan vented outside
- GFCI-protected outlets and good lighting
- Moisture-resistant board or tile backer at wet areas
- Final plumbing inspection after fixtures are set
Who does the plumbing?
Plumbing work has its own license requirements in Idaho. The finishing company usually brings in a plumbing contractor for drains and venting, and the city inspects the rough-in and final. If you live outside city limits, ask who issues and inspects the plumbing permit for your address; Jefferson County, for example, notes that mechanical systems there are permitted and inspected by the state.
Why plan for winter
A basement bath's supply lines and drain run along cold foundation walls in an Idaho Falls winter. Keep pipes on the warm side of the insulation, and make sure the fan duct is insulated and sloped so condensation doesn't drip back.
What affects the cost?
- Using a rough-in versus cutting the slab
- Distance to the main drain and stack
- Gravity drain or ejector system
- Half bath versus full bath with tile
- Fixtures, vanity and fan
Where we can connect you
Common questions
Can a basement bathroom go anywhere in the basement?
It's easiest near the main drain and an existing rough-in. Farther away usually means more slab cutting or a pump.
Does a basement bathroom need a window?
No, if it has an exhaust fan vented to the outside. The contractor will size the fan.
Is a separate permit needed for the plumbing?
Plumbing is inspected as part of the basement finish in Idaho Falls, with rough-in and final plumbing inspections. Ask the contractor how permits are split at your address.
Related services
More background: Idaho Falls basement finishing guide.
Need more room without moving?
Call and a local basement finishing contractor will walk the basement and the permit with you.