Last year, three charter schools in the District stood on the brink of closing. They needed help. Fast. Two turned to the Friendship Public Charter network. The third received a lifeline from the KIPP DC charter network.

And now, Friendship may rescue yet another struggling charter campus. D.C. education officials are considering a proposal for Friendship to take over Achievement Prep-Wahler Place Middle School in Southeast Washington.

KIPP DC and Friendship, the city’s two largest charter networks, have grown bigger in recent years as they take over floundering charter campuses, revamping the schools and adding the campuses to their already extensive and well-regarded portfolios.

The networks are poised to educate more than 11,500 public school students in the coming years — more than 11 percent of the city’s public school population.

But how big is too big for an education sector that began with a promise of a collection of independent campuses meant to stand as an alternative to the bureaucratic thicket of the traditional school system?

“If something is working, it makes sense to build on it,” said Susan Schaeffler, the founder and chief executive of KIPP DC. “We did not do this overnight.”

When charter schools entered the nation’s capital in the 1990s, their leaders pitched the District as fertile ground to experiment in urban education.

Twenty-five years later, KIPP DC — which started in the District with a single middle school in 2001 — serves 6,800 students on seven campuses. The network plans to build a $90 million high school and recreation center in Southeast Washington next year that will eventually educate 800 students.

KIPP DC has a central office staff of 120 employees who help with operations on all of its campuses. By comparison, the traditional public school system educates 53,000 students and has more than 1,000 central office employees.

Friendship educates 4,200 D.C. students, and 73 of its more than 800 employees work in the D.C. headquarters. Its 16 schools have received a mix of mid- and high-level rankings from the D.C. Public Charter School Board, which regulates charter campuses.

Friendship and KIPP — with most of their schools in largely African American neighborhoods — have become mini-school systems, educating students in all grades on multiple campuses. Still, leaders at KIPP DC and Friendship said they are agile organizations and are delivering on their original promise of providing students a high-quality education.

But they also acknowledge they have benefited from their size. When KIPP DC noticed a dearth of teaching and leadership talent in the city, it created its own teacher-training program. KIPP has curriculum specialists and can share other high-salaried employees among its multiple campuses.

Friendship, which also has its own teacher-development program, broke ground last week on a $4 million athletic field and sports complex for its high school students. It has a more robust athletic program than most charter campuses.

The networks’ big names in the charter sector help lure private donations.

Candice Tolliver-Burns, spokes­woman for the Friendship network, said the network has enough resources and staff that it can quickly assume operations of a fully enrolled school without hurting existing campuses. Most KIPP and Friendship schools have waiting lists of students hoping to attend.

“We have the resources and expertise to dispatch and invest in those schools so that those students can continue growing and learning without any interruption,” Tolliver-Burns said. 

Scott Pearson, chair of the D.C. Public Charter School Board, said he has grappled with the question of what happens if a charter network becomes “too big to fail.” Eight years ago, he said, the board passed a policy allowing it to close a single campus in a charter network instead of the entire network. He said this makes it more manageable to hold the large networks accountable.

He said he does not believe the networks have grown too big, but he wishes the city had more networks capable of assuming operations of low-performing schools.

Pearson said KIPP, Friendship and the traditional public school system have proved most successful in taking over failing schools. KIPP DC has taken over two schools — Somerset Prep DC and Arts and Technology Academy. If the Wahler Place deal is finalized, that would be the third struggling campus Friendship has taken over, after it assumed control of Ideal Academy public charter and City Arts and Prep last year.

A charter network often assumes the assets — and debts — of the school it is taking over, including its coveted facilities.

There’s a measure of irony in Achievement Prep being taken over by another charter operator. In 2013, Achievement Prep was the suitor, assuming control of Septima Clark, an all-boys school that the charter board closed amid low academic performance. But it turned out that Achievement Prep — which has a more successful elementary school that will remain open — could not turn around the school.

The push to have more successful charter networks take over floundering campuses reflects a philosophy among local charter leaders that displacing students from a low-performing school should be a last resort.

“We would like to see more schools stepping up that are capable of taking over schools,” Pearson said. “We would like more options, but it hasn’t worked out that way.”

National charter leaders said the frequent takeover of D.C. schools by other charter operators is a trend rarely seen outside the District. Still, other cities have large charter networks. In Los Angeles, Aspire Public Schools operates 11 schools.

In New York, Success Academy Charter Schools educates 18,000 students. But that’s a small share of the more than 1 million students in the city’s traditional public school system and of the 120,000 charter students.

James Merriman, chief executive of the advocacy group New York City Charter School Center, said one of the big challenges facing schools is a shortage of teachers and strong leaders. Like KIPP and Friendship, other large charter networks are able to nurture their own talent, he said.

“This is not necessarily what people had in mind,” Merriman said. “But on the other hand, there is no doubt that in the current environment, the results for the networks are generally higher.”