Ranchers, split-levels and Cape Cods that rest comfortably on manicured half-acre lots guard a secret in Rolling Acres, a 1950s subdivision tucked between Frederick Road and Route 40.

It isn't one that homeowners have pledged to keep to themselves, interestingly enough, but one they want to share.

After one enters the Ellicott City community by way of Dogwood Road and takes a few turns, a long driveway appears on an unassuming cul-de-sac, marked by an oversized white mailbox at the curb. Closer inspection reveals painted lettering: "Nob Hill Swim Club."

There's a pool in the neighborhood! Who knew? Not enough people nowadays, homeowners say.

Originally called Nob Hill, the community consists of 99 houses whose inhabitants are equal part-owners of the 90,000-gallon pool, which lies in a wooded alcove. Its location is totally obscured within the community, though residents say it's visible from Route 40.

"People driving past can see it, but we've heard they can't figure out how to get to it," said Mike Baker, who has lived in Rolling Acres for 20 years.

Knowing that, pool members recently erected a large banner facing the four-lane highway, but it was taken down by the state because the sign's stakes were driven into a right-of-way, residents said.

Now the same white vinyl banner proclaims "Affordable pool memberships" as it hangs between two pine trees in a yard chosen for its strategic location near the neighborhood's Route 40 entrance. Kids shrouded in beach towels walked past the sign in the direction of the pool one especially warm evening last week.

Attempts to attract public attention to the amenity were prompted recently by an all-too-obvious reason: As the neighborhood has aged, and homeowners and their children along with it, memberships are down. Some people want more choices, so they belong to the Columbia Association; others want a larger facility, so they join the YMCA on nearby Montgomery Road.

"Nob Hill is a small community pool, and that fits a certain dynamic," said Tina Fullarton, who moved to Rolling Acres two years ago because of the pool and serves as vice president of membership.

"But it never gets crowded here," she said, "and everyone knows your name."

As recently as 2001, the swim club came off a decade-long membership high of 140 families and maintained a waiting list, said Baker, who was pool president at the time and now serves as vice president of operations.

During those years, between a fourth and a fifth of the swim club's members came from within the neighborhood and 75 percent to 80 percent came from nearby homes.

While that ratio has remained constant throughout the years, membership is down by 40 percent, to 85 families, Fullarton said, turning the unofficial secret no one used to feel a need to broadcast into a frequent topic of discussion.

"This is such a welcoming environment, and we'd love to have more families join us," said Fullarton, who noted that her 16-year-old daughter is a fan of the private parties that can be arranged there before or after regular pool hours.

Baker and his wife, Susie, who joined as soon as they moved into the neighborhood in 1990, raised their two children there, both of whom eventually became lifeguards and pool managers. Their son, Rob Roy Baker, has been the manager for three years.

For Rob, 28, working at the pool is second nature, even though he works year-round as a 911 dispatcher first-class.

"It's such a quaint and amazing pool," Rob said of his reason for returning each summer. "Even when I'm not on duty, I'm the one kids always come to because they know me."

David Giangrandi, who was a Nob Hill member as a kid living in Normandy Heights, made the decision to return to his childhood stamping grounds for more than sentimental reasons. He rounded up his three kids and took them on a tour of the area's swim clubs before choosing which one to join.

"I told them we were going on a reconnaissance mission to check out pools, and this was the one where my kids were happy," Giangrandi said. "I thought they might want an Olympic-sized pool since they spend several weeks in the summer visiting my wife's family in Germany and use one there.

"And I even took them to Five Oaks in Catonsville, where there's a high-meter board," he said. "But they liked the size and features of Nob Hill."

Giangrandi's wife, Christa, said her husband is also a big fan, so much so that when she asked him where he'd like to celebrate his 40th birthday three years ago, he chose Nob Hill.

"Hey, I'm a father and I want to celebrate with my kids," said Giangrandi, who has an August birthday. "So, where else would I want my party to be?"

Petra Fochios, who dubbed the pool "Nob Hill Summer Camp" since her four kids spend a great deal of time there once school is out, said it's a great place to be because members all know one another.

"If your kids misbehave when you're not there, some other mother will yell at them, which I'm totally fine with," she said with a chuckle.

Van Fochios, a 19-year-old college student who's been a member since age 3, has been a lifeguard at Nob Hill for four years and has fond memories of all his summers there.

"We kids were all pool rats and came here all the time, even when it was raining," he said.

Child members younger than 12 are allowed to swim unsupervised by their parents, as long as the parents fill out and sign a permission form. Lifeguards also give the kids a three-part test to evaluate their swimming skills.

"And the reason that works is that each guard learns who your children are and no one's treated like a number," Petra Fochios said.

"This pool really is like a small town in that sense," Christa Giangrandi said.

Lending Nob Hill an additional dollop of old-fashioned appeal are its horseshoes pit, sand volleyball court and ping-pong table, and a new redwood play area that was recently installed. There is no concession stand, but snacks and drinks are sold at a corner table and members can bring in food or order pizza delivery.

As advertised, membership rates really are reasonable, Fullarton said, and seniors can pay a low guest rate when their grandchildren visit.

"It's a small, intimate pool," said Susie Baker, adding that the Fourth of July is an all-day blowout at Nob Hill and one of its busiest and most fun occasions.

"It's just an amazing place to spend the summer," she said.