The explosive growth in Prince William County’s western end during the past decade transformed farmland into bustling subdivisions with families who sought to sidestep high living costs inside the Beltway.

Brentsville’s development, particularly how it was managed, has led to a primary-election challenge for eight-year incumbent Supervisor W.S. Covington III.

Covington, who has represented the fastest-growing district for eight years, is being challenged by newcomer Jeanine Lawson in the Republican primary Aug. 23. The mother of two hopes to gather support from other parents frustrated with what she says are overcrowded schools and clogged roadways.

“The county needs new leadership,” said Lawson, 41. “The district has grown, and that’s great when the infrastructure comes with it. But that’s not what happened. . . . This mismanaged growth has affected the quality of life of Prince William residents.”

Covington countercharges that Lawson is blaming the wrong people. He said the board is trying to alleviate problems created by residential development projects approved by a previous board.

The Brentsville primary will probably be the county’s closest race, and who wins depends on which candidate can get the most voters to the polls during the summer vacation season. The contest in the Republican-leaning district is one of three county primaries for supervisor seats: Republican incumbent Martin E. Nohe will face Bob Pugh in the Coles District, and five residents will vie for the Republican nomination for the open Gainesville seat. (Republican John T. Stirrup Jr. is leaving to run for state Senate.)

Prince William’s overall population grew almost 40 percent in the past 10 years, with the Linton Hall corridor in Covington’s district adding 28,000 residents, according to the 2010 census. Brentsville residents have the nation’s worst commute, according to a 2009 census report.

Lawson, who moved to Brentsville 16 years ago, said the county has favored developers and not gotten its fair share of proffers. Taxpayers are funding road projects instead of developers, she said, and residential growth continues despite packed schools and roads.

“I am committed to not approving any residential units until the market is healthier or the infrastructure is in place,” Lawson said.

Covington, however, said Lawson “is living in the past and using old data” to make her case.

Covington said that as supervisor, he pushed for a resolution in 2005 that halted residential growth for a year and advocated for another measure last year that stopped residential building until three new schools opened this fall. Covington said that while he has been in office, 11 schools opened in Brentsville, including the governor’s school and an alternative school, and countless road projects were completed, including the widening of Linton Hall Road.

The 47-year-old father of three, a lawyer who is in line to be the next chair of Virginia Railway Express, has also led the efforts to bring VRE to Gainesville and possibly Haymarket; VRE projects that such an extension could take 5,000 cars off the road.

“Roads were a big thing for me; it’s why I ran the first time and why I am running again,” Covington said. “With [Stirrup] leaving, the western end needs someone who is experienced and knows the area.”

The differences between Covington and Lawson extend to economic development, the proposed bi-county parkway and Prince William’s Rural Crescent.

Lawson said the county has not “aggressively” targeted professional jobs, and she has signed a pledge to keep large residential and commercial developments out of the Rural Crescent — 117,000 acres of mostly open space with some agricultural resources. She is against the parkway, which would connect the county to the Dulles Airport corridor, because it cuts through the crescent.

Covington, however, points to a CNN Money report that named Prince William as the leader in job growth among Virginia localities and also in the Washington region, between 2000 and 2009. Although he did not sign the Rural Crescent pledge, Covington said he supports protecting the county’s natural resources. He said he backs the bi-county parkway because it would help commuters and spur economic development.

Concerns about growth and residential development are also a leading issue in the primary in the Coles District, where eight-year incumbent Supervisor Martin E. Nohe (R) is trying to beat back challenger Bob Pugh in somewhat different terrain.

Prince William redistricted the area because of 2010 census numbers. Pugh, 54, said the district’s residential development was poorly managed by a county that imposes high taxes but needs to expand its commercial base. He said Nohe, 41, too often thinks regionally about issues that deserve a local approach.

“I don’t think we are in bad shape now, but if we continue on the same course, I don’t think [Prince William] will be a desirable community,” said Pugh, who owns a financial planning and investment firm. “Our biggest problem is overdevelopment.”

Like Covington, Nohe, who is president of a local appliance business, pointed to the rating from CNN Money and said he is committed to expanding the commercial base. Nohe said it is key to take a regional approach on certain issues, such as transportation.

“Traffic jams don’t respect jurisdictional boundaries,” Nohe said. “We have to understand what’s going on [across county lines] to make reasonable decisions.”

The two also differ on the Rural Crescent. Pugh was the first candidate to sign the pledge in June; Nohe has not.

The issues remain much the same in Gainesville, another growing district in the western end. There, Gainesville planning commissioner Martha Hendley, 68; Steven Botello, 52; Suzanne Miller, 48; Peter Candland, 37; and Michael High, 47, hope to win over voters by next week.

Hendley, Miller and High signed the Rural Crescent pledge. Hendley and High have taken a strong stance against residential growth until infrastructure is in place, while Miller is trying to stand out from the pack by pushing job creation and her “made in Prince William” slogan.

Botello and Candland have touted that their “real world” business experience will help them foster economic growth.