Power companies across the region have declared an official end to the lingering electrical outages linked to last month’s derecho thunderstorms, acknowledging customers’ many hardships while saying they think they did a good job getting the juice flowing again.

“I am comfortable that we will be able to demonstrate . . . that we performed well considering the severity of the event, ” said Felecia Greer, the customer advocate at Pepco, which serves the District and Maryland suburbs. “There was just no way to prepare for this level of damage.”

At Dominion Virginia, which serves Northern Virginia, spokeswoman Le-Ha Anderson said restoration took less time than after hurricanes Isabel and Irene.

“We think we had a good response to the June 29 event, given that this storm didn’t allow us the preparation time that a hurricane would,” Anderson said. “That said, we still had customers out of power for a week. We’re still looking at our response and seeing what we could have done better.”

BGE spokesman Rob Gould said that improvements in how crews are dispatched also seem to have reduced how long teams idled between assignments and paid off for BGE’s restoration. In this storm and in Hurricane Irene, Gould said, the utility had about the same number of outages and restored power both times in just over eight days. But after the derecho, BGE hit that mark using 4,700 workers, fewer than the 6,300 who worked during Irene.

Estimates of the cost of restoring power to more than 1 million customers begin in the millions of dollars, but definite figures will have to wait for the compilation of official storm reports.

Pepco has three weeks to file a comprehensive accounting with public service commissions in the District and Maryland. The reports will detail how many homes lost power and for how long, as well as how many repair crews responded from out of state. They will assess the company’s accuracy in forecasting when the lights would flicker back on in particular neighborhoods after hundreds of trees came down, wreaking havoc on power lines.

District regulators have announced that they will hold a hearing at which Pepco executives will describe their storm preparation and performance. Maryland officials are expected to hold a similar session, though no date has been announced.

Whether Pepco is determined to have reacted well or poorly will not directly affect rate-increase requests pending in the District and Maryland. There will, however, be an indirect effect. Pepco last week requested a week delay in a decision on a 4 percent rate increase it has requested for its Maryland customers, saying it needed more time to focus on repairing storm damage.

In the long term, however, widespread damage to the electrical grid could cost consumers.

In Maryland and the District, Pepco may seek to recoup its losses in future rate increase cases. Those charges are often spread over a number of years, said Terri Czarski, the deputy people’s counsel for Maryland.In the past, the company and consumer advocates have disagreed at times over which costs are reasonable to pass along to customers, and over how long customers should have to pay, she said.

In Virginia, repairing storm damage is considered a cost of business for Dominion, Anderson said. Even so, the company is free to cite extraordinary repair expenses when seeking future rate increases.

Some public figures are not waiting for final reports before passing judgement on Pepco’s performance.

Montgomery County Council President Roger Berliner (D-Potomac-Bethesda) blasted the company during a Monday news conference, where he estimated that the outage could cost businesses and consumers there as much as $1 billion.

“No issue is more important than reliable electric power,” Berliner said. “And the simple and sad truth is that we don’t have it, and we haven’t had it for a long time.”

Pepco needs to improve communications and hire more repair crews, Berliner said.

After the June 29 storm, Pepco and other area utilities brought in crews from as far away as Canada.

Berliner favors fining companies for poor performance.

“The consequences need to be real. They need to be big enough to change Pepco’s behavior,” he said, calling a $1 million fine levied last year by the Maryland Public Service Commission a “slap on the wrist.”

“You get to $20 million, you get to $30 million, to $40 million, then you start getting people’s attention,” Berliner said.

District People’s Counsel Sandra Mattavous-Frye said she is waiting for detailed data before determining where Pepco may have faltered. But she said improvements are needed, especially in communicating with customers.

“It doesn’t take a nuclear scientist to see the system is failing,” Mattavous-Frye said. “I know Pepco is not prepared to meet another storm of this magnitude this summer, without having the same result. Something has to be done about that…”

Meanwhile, more recent storms resulted in new power outages. Dominion reported 30,000 outages in Northern Virginia from a storm Sunday night.

As of 4:15 p.m. Monday, 591 customers were without power in Fauquier County and 1,500 were in the dark in Fredericksburg. All service was expected to be restored by midnight.

Michael S. Rosenwald, Mary Pat Flaherty and Patricia Sullivan contributed to this report.