Nation's Capital Swim Club coach Bruce Gemmell gives out instructions to the elite swimmers during practice at Georgetown Prep's pool earlier this month. (Katherine Frey/The Washington Post)

It’s 6:15 a.m. on a Sunday, and more than a dozen parents are arrayed in the lobby of Alexandria’s Lee District Recreation Center, silently reading newspapers, paying bills and doing some Christmas shopping online. A few others wander in around 9 a.m., bleary-eyed and rumpled, after alarm clocks rouse them from naps in their cars outside.

To thousands of parents throughout the Washington area, it’s a familiar ritual weekends and weekdays alike: rising in darkness, battling traffic and devising ways to productively spend time while their children swim lap after lap after lap.

Though not what might be expected of a congested metropolis prone to snowpocalypses and sweltering humidity, Washington has become a swimming hotbed known not only for producing Olympic gold medalists Mark Henderson, Tom Dolan, Mike Barrowman, Ed Moses and Katie Ledecky but also for churning out a steady stream of scholarship athletes from a pipeline brimming with talent.

Multiple factors account for the phenomenon.

The first dates back more than 50 years, says Riley Eaton, general chairman of the board of directors of Potomac Valley Swimming and a former coach with the Rockville-Montgomery Swim Club, pointing to the development of suburban subdivisions, nearly all of which boasted a community pool and tennis courts.

Summer swim leagues formed to provide basic instruction couched in fun and games, and now there are more than 30,000 summer-league swimmers in the area. And the subset of youngsters who wanted to stick with the sport once school started fueled a demand for year-round teams.

Today, those clubs — Rockville-Montgomery and Nation’s Capital Swim Club (NCAP) in particular — dominate competition in Northern Virginia, the District and Montgomery and Prince George’s counties, which is governed by Potomac Valley Swimming.

(NCAP changed its name from Curl-Burke Swim Club in September after allegations of a sexual relationship with a swimmer were made against the club’s former owner, head coach and namesake, Rick Curl.)

Despite having the smallest geographical footprint among the 59 competitive regions designated by USA Swimming, the sport’s national governing body, Potomac Valley has the fourth-most participants in the country, Eaton says, with 10,500 swimmers, and Rockville-Montgomery and NCAP boast numerous national and junior national titles.

And it’s growing at a rate that’s straining the capacity of the area’s public and private pools.

“There aren’t many new pools being built,” says Tom Ugast, chief executive of NCAP. “And that’s the struggle we’re going to have: We have nearly 11,000 athletes.”

No easy swim meets

The sport’s tremendous growth has been a boon in a competitive sense, ratcheting up the level of competition at all age groups as top swimmers from one team push those from others — whether NCAP, Rockville-Montgomery, Machine Aquatic or others.

Earlier this month, the region’s best age-group swimmers faced off with their counterparts from up and down the East Coast in the 10th annual Tom Dolan Invitational at the University of Maryland’s Eppley Center. Among them were Good Counsel’s Jack Conger, considered among the top recruits in the country, who’ll swim at Texas next season; Janet Hu, a junior who’s pegged as one of the top two or three recruits next season; Ledecky, the 2012 Olympic gold medalist in the 800 meters and the country’s top sophomore; and 12-year-phenom Cassidy Bayer, who has set age-group records in the butterfly.

“If you don’t get better, you just get left by the wayside,” Eaton says of the cauldron of competition close to home. “We’re in an environment where there aren’t any easy swim meets any more. You have to keep getting better.”

And the ranks of aspiring Olympians spike after each Summer Games.

According to Pat Hogan, USA Swimming’s director of club development, participation in youth swimming grew 5.9 percent following the 2000 Sydney Games, 7.2 percent after the 2004 Atlanta Games and a record 11.2 percent following Phelps’s unprecedented eight gold medals at the 2008 Beijing Games. It’s currently tracking at more than 10 percent following the 2012 London Olympics, where Phelps became the most decorated Olympian of all time, earning his 22nd medal, and Ledecky, a sophomore at Stone Ridge School of the Sacred Heart in Bethesda, won gold.

Eaton witnessed the inspirational power of Ledecky’s achievement first-hand during a “Swim-posium” that Potomac Valley held for young swimmers and their parents this fall. Ledecky was the star attraction, and she signed autographs for more than an hour as one child after another came up to marvel at her.

One little girl, he recalls, told Ledecky: “I took down all my horse posters and put up yours! How many hours a day do you train?”

Life in the lanes

On a recent Saturday morning at Georgetown Preparatory School, there Ledecky was, finishing her morning workout as dozens of 9- to 13-year-olds arrived at the pool for their 9 a.m. practice, flippers and goggles in hand. Because one of the coaches was out sick, Bruce Gemmell, who has coached Ledecky since her return from London, took on the 9- and 10-year-olds who were still learning basic strokes.

“I’m so happy you’re going to be our coach today!” one awestruck little boy gushed at Gemmell. “In my opinion, you’re one of the best!”

Several lanes over and on the opposite side of the pool, Mary Dowling, a Sidwell Friends School graduate who competed at Villanova, worked with more advanced 11- to 13-year-olds, who started with a series of stretches on the pool deck. Then she sorted them into four lanes, roughly seven swimmers per lane, and they popped on their goggles and took off like a school of dolphins through the water, first butterfly kicks using a board, then the backstroke, followed by breaststroke.

With less than three weeks before the Tom Dolan meet, Dowling devoted part of the lesson to finishing races, demonstrating proper form on the deck.

“A great finish can be the difference between a win and a loss,” she said. “It has made the difference between a gold medal and a silver medal! So I want you to be really aggressive at the wall and do a great finish. Eyes down! Arms extended! Keep your legs going.”

Gemmell, meantime, was quizzing his charges on the opposite side of the pool as they bobbed up and down in the water, riveted on his instruction.

“How many strokes did you take? How many breaths?”

The fewer of each, the better. But at this stage, simply getting them to focus on what they were doing in the water, and being accountable for it, is part of the process.

“For so many of our coaches, at one time in our career we coached younger, developing kids,” Gemmell said, explaining his own thrill in coaching Ledecky at 8 a.m., followed by a gaggle of 9-year-olds an hour later. “Getting to the Olympic level is such a process, and they need to be doing the right things in the formative years.”