San Francisco startup, SOAK, inspired by Amsterdam saunas and dubbed, “an urban bathhouse for healthy hedonists,” has turned shipping containers into a spa that can be transported to any urban location.

Taking measures to “minimize its hedonistic impact,” the spa can operate entirely off the grid or return excess power to the grid. It bears its own solar hot water and is equipped with systems for photovoltaic to generate all of its own power and for solar thermal collection to heat water, as well as for rainwater collection and grey water filtration.


Designed by Rebar Art & Design, SOAK features a lounge and changing area, garden, rooftop deck and the expected energy-efficient sauna and hot tubs. Half of the water that is used by the hot tubs is harvested from rainwater. Used grey water gets infiltrated, processed through gardens, and then released to the ground. Black water goes into the city’s system; all grey water gets recharged in the aquifer.