But at Episcopal Academy in Newtown Square, in contrast to the state's sports landscape, water polo is more a point of emphasis than a footnote.
Episcopal is one of only about 15 schools in the area that offer the sport, and it has both boys' and girls' teams.
The academy also introduces water polo to third and fourth graders in phys-ed. And it boasts a middle-school program with about 35 youngsters, and it recently began a club team, with the hope of providing the sport beyond the fall scholastic season to students from any school.
"In terms of being competitive with schools in California and on the West Coast, it's not very comparable," Episcopal girls' coach Alicia Keating said of area water polo. "Those kids play water polo every day all year round. And that's what we're striving to have here."
At the high school level, the Churchmen boys compete in the Inter-Ac League with Haverford, Germantown Academy, Malvern Prep, and Penn Charter.
There's no Inter-Ac girls' title, because only Episcopal, GA, and Penn Charter have teams, Keating said. Episcopal and other private schools also compete in the postseason Eastern Prep boys' and girls' tournaments.
Sixteen players are in the Churchmen boys' program, which includes a varsity and junior varsity. The girls are in a rebuilding season with only 11 on the roster and play strictly varsity.
Some Episcopal players have gone on to NCAA Division I teams. Madison Moore is a freshman goalie at Arizona State (NCAA women play in the spring). Christy DiSilvestro is a freshman attack at Harvard, where her brother Kevin, another Episcopal alum, is a junior driver on the men's team.
Jimmy McEntee, an Episcopal senior who has played basketball, hockey, and football - and tore a knee ligament in his freshman football season - calls water polo the most grueling of sports.
"This is up and away, by far, the hardest sport you will ever play and can play," he said. "It's [like] basketball, but you swim instead of walk or run, which is ten thousand times harder. . . . It's constant motion, constant aggressiveness."
Water polo and basketball share some principles. In polo, the offense revolves around the center position, also called the two-meter or hole set. There are seven players on each side, and five form an arc around the two-meter position on offense. On defense, players must guard opponents as well as block passing and driving lanes.
There are four seven-minute quarters, and a 30-second shot clock is used.
"It takes a lot of stamina," said Episcopal boys' coach Damon Newman, a former Wissahickon player who also guides the Villanova women's team. "It's like a rugby game with swimming.
"It's definitely a strenuous sport where people are holding onto you, grabbing you, kicking you."
Episcopal senior Charlie McGregor started playing in the seventh grade, and grew to appreciate the mental aspect of the sport.
"It's really a thinking game," he said. "There's a lot of motion, and it's a game where you have to really watch everybody in the pool.
"And for me, that's why I love it, because I love to be able to challenge myself to think and see the patterns and see how the play is developing."
Contact staff writer Lou Rabito