Tiny House Bathroom Essentials
Part of our Ideas & Budget Upgrades guides.
Tiny houses combine three constraints: little floor space, limited electrical capacity and often no sewer connection. Choose fixtures that work within all three.
Hot water on 120 V
Big electric tankless units need huge breakers. A 12-gallon 120 V point-of-use heater or 6-gallon model runs on a standard circuit. Propane users can go outdoor propane tankless.
Toilet
On sewer or septic, a 10-inch rough-in toilet saves space. Off-grid, see portable vs composting.
Shower
A 36x36 EPS shower kit creates a tiled corner shower in the smallest footprint.
Ventilation
Tiny spaces fog up fast. An 80 CFM fan keeps moisture out of walls.
Electrical budget
Tiny houses on wheels often run on a 30 or 50 A RV-style hookup. A 13.8-36 kW electric tankless heater would need far more than that. That's why point-of-use tanks on 120 V (6-12 gallon) or propane tankless are the common choices. Add up every load you plan to run at the same time.
Layout ideas
- Combine a 36x36 shower with a wall-hung sink to free floor space.
- Put the water heater above the washer or in a closet with access panels.
- Use a pocket or sliding barn door so the door doesn't swing into the bathroom.
Moisture in small spaces
Steam from a single shower has nowhere to go in a tiny house; it ends up on windows and inside walls. An exhaust fan vented outdoors with a timer or humidity control is not optional. Choose mold-resistant drywall or panels for bathroom walls.
Weight on wheels
For tiny houses on trailers, every pound counts. Acrylic shower pans and EPS foam curb kits are much lighter than mortar beds and tile-heavy designs.
Frequently asked questions
What's the smallest practical shower size?
32x32 inches is the code minimum in many areas; 36x36 is more comfortable.
Can a tiny house use a tankless heater?
Yes, propane is common; electric tankless often needs more amperage than a tiny house service provides.
What's the smallest toilet for a tiny house?
Compact toilets with 10-inch rough-in or portable/composting toilets save the most space.
Can I use an RV water heater in a tiny house?
Some tiny houses use RV-style propane heaters; check local codes for permanent dwellings.
How do I prevent condensation in a tiny bathroom?
Use a vented exhaust fan and keep the bathroom door open after showers.
Is a wet bath a good idea?
Wet baths save space by combining shower and toilet areas, common in tiny homes and RVs.