Does a Sauna Need a Floor Drain?

Usually not for a home sauna. A residential sauna where you ladle a little water on the rocks does not put enough water on the floor to need a drain. What it does need is a floor that sheds water, is easy to wipe up, and dries fast. Drains become worth it in commercial saunas and in rooms that get washed down.

Why most home saunas do without one

People picture a sauna as a wet room, but a traditional sauna is mostly a dry room. The water you ladle on the rocks turns to steam almost immediately. What reaches the floor is sweat and the occasional splash, and that is easily handled by wiping and by letting the room dry out. A drain adds cost, and a badly done drain adds a hole that leaks heat and can carry smells back into the room.

When a drain does make sense

• Commercial or shared saunas. Higher use and regular cleaning mean real volumes of water.
• Rooms that get hosed down. If you intend to wash the sauna out rather than wipe it, you need somewhere for that water to go.
• Sauna and shower in one room. Then you are draining the shower anyway.
• An existing drain is right there. If the sauna is going into a basement or bathroom that already has one, use it.

What matters more than a drain

• A floor that sheds water. A surface that does not soak it up and is easy to wipe.
• Ventilation and drying. The room drying out fully after each use is worth more than any drain. See sauna ventilation.
• Good habits. Sit on a towel, wipe the benches, leave the door open afterwards.

If you do fit one

A sauna drain needs a proper trap so sewer gas cannot come up into the room, the floor needs a slight slope to it, and it has to be done so it does not become a cold air leak. If a drain is in your plan, get it designed in at the start along with the plumbing, not cut in later.

Procraft builds Western red cedar saunas and makes four CSA-approved electric sauna heaters from 4.5kW to 9kW. See the heaters, read about Western red cedar, or see how installation works.