Your average neighborhood day spa can generate a huge waste stream: towels and robes need to be laundered, hot and cold plunge pools need to be refilled, not to mention the energy required for the upkeep of temperature-appropriate treatment rooms and atmospheric landscaping that telegraphs "natural" and "relaxing."
Global spa tourism is a $180 billion industry. Water and energy use can vary hugely depending on the size of a spa and the kinds of services it offers; one 2007 study in Australia found that the average spa client used 21 gallons (plus or minus 10 gallons) of water per visit. A water-focused treatment could more than double that.
"A day spa can have two treatment rooms and a laundry going 24 hours a day," says Beth McGroarty, who conducts research for the Global Spa and Wellness Summit. "Or it can be a multi-level water spa that you spend all day at, so big that it's an amusement park of water." While there have been piecemeal efforts within the spa industry to reduce water and energy use and boost recycling, the average day spa remains an indisputable resource-guzzler. But what if you could change the physical fundamentals to create an alternative model that works more efficiently, relies on solar, perhaps uses less space?
One such experiment is being undertaken by San Francisco-based Nell Waters (yup, that's her real name). Waters is launching a campaign to bring a greener type of urban bathhouse to the Bay Area, called SOAK.
Waters and her team have talked with city planners and lined up a site on the east side of the city in an old light industrial area (exact location is still hush-hush). The "proof-of-concept" project uses two old cargo containers designed by San Francisco's Rebar, the firm that designed the city's popular parklets, with help from engineers at ARUP.
"The question for us was, can we introduce a new kind of experience in an industry that hasn't had any change in it for the last 40 to 50 years?" says Waters. "And can we do it without risking the things that typically come along with a traditional day spa, with heavy water and energy use?"
One hundred percent of the energy budget for SOAK is designed to come from off-grid solar panels mounted on the roof. Solar water heaters and photo-voltaics then warm up bathwater. Half the water in the soaking tubs will be filtered rainwater; after bathing, the resulting gray-water is treated onsite and used for garden irrigation or returned to the city aquifer. High-efficiency hot tubs use exchanger pumps that take warmth from old bathwater to heat fresh batches.
Radiant heat warms the floors and the induction sauna, and insulated walls keep heat inside the containers. Outside, a dynamic dashboard in the public courtyard gives real-time data on water and energy use to guests and passersby. It's meant to be educational. The placement of the containers — in vacant sites near public transit — is intended to maximize urban space.
SOAK won’t offer any salt scrubs, facials, or silence gongs. Instead, there will be hot pools, cold plunge buckets, a sauna, and a solarium with great views of the city, all available for a $25 drop-in fee (with reduced fees available, much like a gym membership). "It’s less about people carving out a three-hour chunk of time and paying exorbitant costs and more about dropping in," Waters says.
One thing is for sure: Waters won’t be spending a whopping $10,000 a month to re-grout tiles in her tubs the way similar-sized spas do, as she discovered in her research. If SOAK’s Kickstarter campaign is successful, the project’s mindful engineering could well inform the future of spa design in a city near you.