What Electrical and Plumbing Work Does a Steam Shower Need?

Published September 27, 2026

Summary

A steam shower needs more than ordinary shower plumbing. The generator needs its own electrical supply, a cold-water feed, a steam line to the enclosure, and whatever drain or flushing arrangement the manufacturer specifies. The exact requirements come from the generator model, so choose the equipment before the electrician and plumber finish the rough-in.

Choose the generator before rough-in starts

The generator determines much of the work hidden behind the finished bathroom. Its output and model determine the electrical requirements, while its installation manual sets the rules for the water connection, steam line, drainage, and service access.

That is why it is risky to rough in a bathroom for "a steam shower" before the actual generator has been selected. A change in equipment can mean a change in wiring, pipe routing, or generator location.

The electrical work is model-specific

Residential steam generators are large electrical loads, and the requirements change with the model. ThermaSol's installation manual for its PRO Series III generators shows the range: the 6.0 kW PROIII-84 draws 28 amps and uses a NEMA 6-30P plug, the 8 and 10 kW models use NEMA 6-50P, and everything from the 11 kW PROIII-395 (55 amps) up to the 24 kW PROIII-1200 (110 amps) is hardwired. All of them run on 208 to 240 volts, single phase, each on its own breaker, and ThermaSol requires a licensed electrician for all electrical work.

The plumber has more than one connection to plan

ThermaSol's manual has the plumber tee off the cold water line, run copper to the generator's 3/8-inch inlet, and put a brass shutoff valve in an accessible spot, with an in-line filter recommended. Galvanized fittings, PEX, and PVC are ruled out. MrSteam recommends a pressure-reducing valve to cut water intake noise.

The drain is a separate connection. ThermaSol includes a stainless drain pan and has its 3/4-inch drain plumbed to an approved drain. MrSteam recommends a condensation pan and notes that some building codes require one.

The steam line is its own part of the job. It carries hot vapor from the generator to the steam head and has to follow the manufacturer's rules for material and slope.

Coordinate the trades before the walls close

The steam head, control wiring, generator location, water feed, electrical supply, and waterproofed penetrations all meet in the same small project. The control cable is easy to forget. ThermaSol supplies a 50-foot cable, recommends running it in conduit, and warns against wrapping it around the steam line, where the heat can melt it. MrSteam's iSteamX control comes with a 30-foot cable (60 feet optional) that belongs in its own 1-inch conduit, away from power lines and steam piping.

Give the electrician, plumber, tile contractor, and glass contractor the same drawing and the same generator manual. ThermaSol's manual says all plumbing is to be done by a qualified licensed plumber, and MrSteam recommends a licensed plumber, electrician, or contractor who is familiar with steam.

Sources

Specifications, prices and installation requirements are as the makers published them on these pages on the date above and can change. Check the current manual and the retailer before you buy.