The first thing people see and hear upon entering St. David's Episcopal Church in Ashburn is the water. It is churning and gurgling in an immersion baptistery smack-dab in the middle of the center aisle.

"The baptistery . . . is at the center of our life," said the Rev. Stephen McWhorter, St. David's rector.

Nearly every rite in this parish of nearly 1,000 congregants takes place around this one-of-a-kind baptistery, a particularly unusual feature for an Episcopal church.

Although most infant baptisms at St. David's take place at the adjacent font, almost all baptisms of teenagers and adults have been conducted by immersion since the church's main building opened in 1999. The baptistery is also used for funerals, in which the casket is laid across four wooden beams resting inches above the water to represent the full circle from baptism to death and the promise of resurrection. Brides walk around the baptistery on their way down the aisle, as do worshipers taking Communion, reminding all of the centrality of their baptismal vows to the Christian life, McWhorter said.

As part of the worldwide Anglican Communion, the Episcopal Church usually baptizes by infusion -- the pouring of water -- rather than by immersion. But as McWhorter is quick to point out, the Book of Common Prayer, the church's official liturgical book, says the priest "immerses, or pours water upon, the candidate," making either option valid. Immersion is how Jesus was baptized, he noted.

During his 38 years as a priest, McWhorter, who plans to retire at the end of this year, increasingly sought opportunities to immerse -- in the ocean or a pool or at a Baptist church with a baptistery.

"There is psychological and spiritual depth to going into the water and being buried with Christ to share in his resurrection," McWhorter said. He said that watching the rite in a large baptistery can also be inspirational to the congregation. "It didn't make sense to have a large church with a baptistery the size of a birdbath," he said.

McWhorter speculated that the Episcopal Church has moved away from the ancient ritual of immersion because "it's not tidy." During a baptism, McWhorter, dressed in a white robe and tennis shoes, gets almost as wet as the baptized as he wades down the seven steps into the four-foot-deep baptistery.

The candidates for baptism wear white gowns. One at a time, they enter the baptistery, brimming with more than 1,000 gallons of chlorinated holy water. They cross their arms over their chests, and McWhorter places one hand on their folded arms and another behind their heads.

"I baptize you in the name of the Father, and of the Son and of the Holy Spirit," McWhorter says as he guides each person into the water, keeping the candidate submersed for a moment before bringing him or her back up.

When the priest and the newly baptized emerge from the baptistery, they are dripping wet. Ushers mop the floor while participants quickly change into dry clothes.

Karan Powell, a founding member of St. David's, said it was important to her that her son Erik, now a 12-year-old seventh-grader, be baptized by immersion.

"It's the sense of giving over the whole being to God," said Karan Powell, who lives in Ashburn. "It's not just a dribble on the forehead."

When Erik was 4 months old -- before the church's current baptistery was built -- McWhorter baptized him in a large "lobster kettle" in a building now used by St. David's as a preschool. Powell said the priest briefly submerged the naked infant under the water.

The immersion baptistery is the creation of Gregory Uekman, a Bethesda architect who designs houses and churches. Uekman worked closely with McWhorter over several years while designing his first full-immersion baptistery, which measures 14 feet long by 6 feet at its widest point. It is made of concrete, weighs several tons and is painted in earth tones to create an abstract image of a natural crevice hidden in mountains, Uekman said.

Uekman, who won several architecture awards for his work at St. David's, estimated that the baptistery added $20,000 to the cost of the $2.8 million building.

"You can buy prefabricated baptisteries, but they end up looking like a swimming pool," he said.

Several other congregations have used the baptistery. Grace Bible Church, which usually meets at Harmony Intermediate School in Hamilton, baptized eight members at St. David's on Aug. 14.

"It's a godsend, in plain English," to be able to borrow the baptistery, said Pastor Dan Towery.

Gateway Community Church in Herndon, a Southern Baptist affiliate that lacks a permanent church building, has held baptisms in a community pool and outdoors in a portable hot tub, but Senior Pastor Ed Allen said St. David's was far better.

"Our folks can sit in the sanctuary, and we're right in the middle," Allen said. "Everybody sees, and the kids can come up front."

Gateway hopes to have its own building by 2007, and Allen said he would like it to be designed like St. David's. In the meantime, he said he hopes McWhorter will continue his generosity with the baptistery.

"You wouldn't think of an Episcopalian church as having a baptistery that would be available for folks who practice adult baptism," Allen said. "It's a great sign of ecumenism and unity on his part."

Although immersion baptisteries at Episcopal churches are relatively uncommon, they are not unheard of. Truro Church in Fairfax City has a baptistery behind the altar and uses it for immersion baptisms twice a year. It is usually covered and not visible during most services.

The baptistery at Grace Episcopal Church in The Plains is in a hallway, and people say it has been used only once. Its covering completely hides it from the congregation.

The Rev. Robert W. Prichard, professor of church history at the Virginia Theological Seminary, said immersion baptism is becoming more common in Episcopal churches, particularly those with new buildings. He said the instructions of immersion in the 1979 Book of Common Prayer, the most recent edition, replaced vaguer wording directing the priest to "dip" the candidate.

A large baptistery "is meant to be a very visible reminder of the sacrament of baptism," said Prichard, who links the trend to a churchwide movement since the 1950s reaffirming the importance of baptism, which had sometimes been overshadowed by the ritual of confirmation. When the Episcopal Church emphasized baptism as the means by which a person becomes a full member of the church and eligible to receive communion, a large immersion baptistery became a way to convey the significance of the sacrament, Prichard said.

He said, however, that the increase in baptisteries in the Episcopal Church was likely to be gradual. "You can't just stick a font of that size into an existing building," he said.

Although having a baptistery in the church and conducting full-immersion baptisms leans toward the Protestant side of the Episcopal heritage, at St. David's it also provides an opportunity for the church's Anglo-Catholics to cross themselves with holy water upon entering the sanctuary, as they might in a Roman Catholic church, McWhorter said.

The baptistery also has served another practical function at St. David's. In January 2000 -- just five months after the church building opened -- a snowstorm brought down a wall and the church's sprinkler system flooded the sanctuary.

According to McWhorter, the damage was not nearly as severe as it could have been. To drain several inches of standing water, church officials simply had to open the baptistery's drain and sweep the water in.

"We have a big God," McWhorter said. "That's why we have a big baptistery."

The Rev. Stephen McWhorter stands next to St. David's baptistery, which is 14 feet long and 6 feet wide.McWhorter has increasingly used immersion baptism over his years as a priest.