Umisho

Kenkō Zenrakei Suieibu Umishō is a manga and anime series about a female Highscool Olympic Swimming Team.

Amuro Ninagawa, the female Lead Character has a fondness for Swimming in the Nude aka Skinny Dipping.

Episode 5
Amuro Ninagawa is seen showering herself naked with a garden hose, much to the chagrin of the neighbourhood.