Nude swimming in US indoor pools was common for men and boys from the late s until the early s, but rare for women and girls. For much of that time period, indoor pool use was primarily for physical education or athletic competition, not recreation.
There are regional differences, public indoor pools were more frequently built in Midwest and Northeast states. Male nude swimming had been customary in natural bodies of water , which was not viewed as a social problem until the 18th century.
When the tradition of skinny-dipping in secluded spots had become more visible with urbanization , indoor pools were first built in the 19th century in part to address this issue by moving male swimming indoors. In their own classes, nudity was rare for girls based upon an assumption of modesty , but might include young children.
Prepubescent boys might be nude in mixed-gender settings, including the presence of female staff, [ 3 ] [ 4 ] and spectators at public competitions.
The primary reason given for nudity by officials was for public health, swimming pools being prone to contamination by water-borne diseases. During the early developmental stages of filtration and chlorination, behavioral measures were also needed to keep the water clean. A secondary issue prior to the availability of synthetic fabrics was the clogging of filters by fibers shed by natural fabrics, in particular wool. For male swimmers, both issues were easily addressed by forbidding swimsuits, while female swimmers wore cotton suits that could be steam cleaned and shed less fibers.
