Few topics are as famously Marin as hot tubs. From George Bush slamming “American Taliban” John Walker Lindh as “some misguided Marin County hot-tubber” to local author Cyra McFadden’s 1977 satirical best-seller The Serial: A Year in the Life of Marin County with its undercurrents of wife-swapping, Transcendental Meditation and fern bars, much has been made of locals’ love of the tub. In fact, it’s been said our county has the world’s highest concentration of home spas. But how did this custom soak into our culture in the first place? The answer appears to be proximity. According to Beth Winegarner, who wrote an article for MarinScope in 2003 called “How Marin County Became Synonymous with Hot Tubs,” the first wave came after World War II, when U.S. soldiers stationed in Japan were introduced to the ofuro, a freestanding tub filled with hot water, and brought the idea back home. Among early local adopters were Stinson Beach resident Tad Irvine, who built a tub for himself and his wife in the 1960s, and Al and Barbara Garvey, who built a small wooden tub into a tree by their Fairfax home. Given the social and the therapeutic aspects, popularity surged in the 1970s and is still bubbling along today.