With much of Montgomery County still without power Monday morning, and 911 problems adding to the chaos in across Northern Virginia on Sunday, local officials vowed to press utilities to restore service more quickly.

“I will not accept the timetable of July the 6th, said Montgomery County Executive Isiah Leggett (D), shortly after Pepco announced some homes would not have their power restored until Friday or even later. “Having our citizens go seven days without utilities in my opinion is not the kind of service we should expect.”

With recovery from Friday night’s storm stretching into the week ahead, school officials in the District, Montgomery and Prince George’s counties announced that the schools would be closed Monday for summer sessions and other events. And Maryland declared liberal leave for all non-essential state employees. But all federal agencies are set to open Monday, though officials said workers could take unscheduled leave or telework.

The District government will be open on Monday, officials said. Dozens of city traffic signals remain without power. But Paul Quander, the District’s deputy mayor for public safety and justice, said traffic control officers will be in place at anticipated trouble spots for the Monday morning commute.

As of 5:30 a.m., about 492,000 Washington-area businesses and households remained out of service, according to data furnished on utility Web sites, down from a high of 1.5 million without power in the hours after the storm.

The highest level of outages on Sunday — just shy of 60 percent — was reported for Pepco service to Montgomery County. By Monday morning, Pepco had cut the percentage of households without power to about 42 percent.

Overall in Montgomery County, about 134,312 households and businesses — 38 percent — remained in the dark as of 5:30 a.m. Monday. (While Pepco serves the vast majority of Montgomery County customers, some homes and businesses get electricity from either Baltimore Gas and Electric or Potomac Edison.)

Across Prince George’s County, about 59,400 Pepco customers and 26,300 Baltimore Gas and Electric customers remained without power Monday morning— reflecting 26 percent and 32 percent outage rates, respectively--a significant improvement from overnight. Across Northern Virginia, Dominion Virginia Power reported that the number of customers without power was down to fewer than one in five: 152,789 household and business lacked electricity, about 18 percent of the total served. And in the District, Pepco reported nearly 47,000 without power — also about 18 percent of its customer base.

Dominion officials said most customers would have power by Tuesday, though everyone will not have electricity restored until next weekend. BG&E officials also said it would take most of the week to get all the power up running.

Even though the number of people affected by power outages was dropping, the anger of public officials was palpable on Sunday.

“Nobody will have their boot further up Pepco’s backside than I will,” said Md. Gov. Martin O’Malley (D).

Pepco regional president Thomas H. Graham declined to be more precise other than to offer a “global” estimate that power would be restored to 90 percent of interrupted customers by Friday night.

Responding to concerns aired by many residents that few power crews have been seen in neighborhood streets, executives said that restoration efforts to date have been focused on restoring the high-voltage lines feeding the substations that in turn send power into neighborhoods.

Graham said crews from Missouri, Oklahoma and New Brunswick, Canada, are en route to assist with restoration efforts, but it could be days before some arrive.

“What we’re asking for, everyone is asking for, because we’re all in the same position,” Graham said.

The disruptions of daily life from Friday night’s storm continued throughout the region, as temperatures once against crept past 90 degrees.

Arlington County had 53 intersections without traffic signals on Sunday, an improvement from about 80 on Saturday.

Fairfax County officials said 911 service, which was disrupted as a result of the storm, is only partially restored. People who can’t reach 911 should call 703-691-7561 or 703-691-3680. The 911 service in the city of Manassas was still not working Sunday afternoon, and officials said people needing help should call the police non-emergency number 703-257-8000. Arlington residents were advised to call the non-emergency number 703-558-2222.

Some Northern Virginians who called 911 Saturday were able to get through to police and fire agencies, but not always the ones in their own counties.

Alexandria fielded 36 emergency calls for Arlington, Fairfax, Falls Church and the Virginia State Patrol between 6 a.m. and 6 p.m., city officials said. Alexandria police and fire staff contacted the proper agency by radio and passed the information along. The 911 system is designed to route calls to the nearest jurisdiction if callers can’t get through to their own city or county.

A Verizon spokesman said a power failure in one of its Arlington County facilities caused both technical and mechanical damage that resulted in the 911 outage, but the company has been working around-the-clock to restore full service. The Fairfax and Prince William County 911 call centers are now receiving most emergency calls, said Harry J. Mitchell, Verizon’s director of public relations. But Manassas and Manassas Park are still without 911.

The facility that went down “provided routing for the 911 call centers. Some 911 calls were sent without addresses,” Mitchell said. “Full power is now back on, and we’re working to resolve whatever issues remain so we can get” back to normal.

The 911 failure was a unique event, he said. “We have extensive plans for backup power and they work without a hitch most of the time. In the case of Arlington, this issue affected both our primary and backup systems.”

But officials were not placated.

“I don’t ever remember 911 system going down, and it happened exactly at the time when we needed it most,” said Sharon Bulova, chairman of the Fairfax County Board of Supervisors. “Why was there not a backup or something? ”

Virginia Gov. Robert F. McDonnell (R) said his administration has inquired into the 911 outages affecting Arlington, Fairfax and Prince William counties.

“The best that we’ve gotten at this point is that Verizon itself, with some of their equipment in Arlington, had some of their own storm-related challenges,” McDonnell said. “We just don’t know at this point, was it hardware, software, human error, lightning? I don’t know.”

For all the problems in Northern Virginia, it was Montgomery County that seemed to be the epicenter of disruption, with hundreds of traffic signals still out, and about 70 road closures, almost all in residential neighborhoods. Fire rescue officials said they had logged 2,000 calls for assistance.

Leggett urged people to work at home on Monday or use car pools and public transportation to get to work.

Graham, the Pepco president, said that the storm had caused “extraordinary damage” to Pepco’s system.

“I can only think of one or two occasions when the damage has been greater,” Graham said, naming Hurricane Isabel in September 2003 and a January 1999 ice storm. “This isn’t public relations. This is restoring service customer by customer, circuit by circuit.”

Mike Maxwell, Pepco’s vice president of asset management, said recent efforts to improve reliability have had an impact on preventing customer outages, but he declined to say how much. Maxwell said efforts thus far have been aimed at reducing the number and duration of “blue sky” outages, not related to severe weather.

“Comparatively speaking, you can’t say this was a Pepco issue,” Graham said. “It’s a catastrophic weather event that millions of individuals are experiencing right now.”

Rodney Blevins, Dominion’s vice president of electric distribution operations, said the weekend’s storm caused the third-worst outage in company history. It is the only event in its five largest mass outages, he said, not caused by a hurricane.

Blevins said Dominion has secured 1,000 additional lineworkers, coming from 13 states and Quebec. He estimated that 80 to 85 percent of Dominion customers now in the dark will have power restored by Tuesday night, with 90 to 95 percent getting it by Thursday night. But restoration would not be complete by the weekend. “A lot of hard work happens in that last 5 to 10 percent,” he said.

Both Blevins and a spokesman for Appalachian Power, H. Joseph Jones, said Virginia’s declaration of emergency has helped secure outside crews to help restore power.

“[It] frankly enables us to move external crews in and out of our jurisdiction much more easily,” Jones said. “That’s a big help to us.”

“It’s been helpful for us in terms of competing for and procuring resources, particularly those we were able to get from Quebec,” Blevins added.

BG&E does not expect to be able to restore power until “into the weekend” and is not predicting how many customers may be brought online over the next week, said spokesman Rob Gould.

Changing weather, high demand due to heat and the effects of heat and workload on crews all affect the pace of restoration, Gould said. BG&E has about 750 out-of-state utility workers committed to work on its lines of the 1,000 it estimated would be needed, Gould said.

Facing the prospect of days without electricity, hundreds of thousands of area residents spent the weekend dragging fallen trees from yards and streets, keeping cool in swimming pools and movie theaters, and searching in vain for open gas stations or outlets to charge their cellphones.

Many were irked by the slow pace of recovery.

At a cooling center in Rockville, Cecelia and Charles Plost said they were frustrated that there wasn’t more advance planning for such a storm — and they took exception to the explanation that there wasn’t enough forewarning.

“A real emergency means you don’t have prior knowledge,” Cecelia, 69, said, spending a second day in the center, based at Richard Montgomery High School, with her husband, 70. “They don’t have a plan for an emergency if they are defending that they need forewarning for an emergency.”

She said officials should have been “a lot more prepared.”

But others said they understood the difficulties caused by a mass outage.

Lynne McConnell, 55, of Derwood, sitting with her parents at a Rockville cooling center, said her power returned late Saturday while her parents, who live in Rockville, we’re still powerless Sunday.

“My neighbors are complaining a lot, but I keep thinking, what’s Pepco supposed to do? It was a large storm. They’re doing the best they can,” she said.

With power out for so many, air conditioned churches were popular on Sunday morning.

Elder David Spraddlin at University Park Church of Christ in Hyattsville made a point of letting prospective worshippers know “we have air conditioning and power.”

Peter Davidson, 54, said he headed to St. Augustine Catholic Church in northwest Washington to escape the heat. If the heat wave continued, he said, he might prevail on a friend with air conditioning to take him in.

“We’ll just have to see how bad it gets,” Davidson said.

The storms caused at least five deaths in the region. Two elderly women were crushed by trees that fell through their roofs, two drivers were killed in their cars by fallen trees, and a man was electrocuted by a downed power line. An Alexandria man whose boat capsized in the Chesapeake Bay was missing and believed to have drowned.

States of emergency were declared in Maryland, Virginia and the District of Columbia.

The Falls Church water utility advised customers in parts of Tyson’s Corner, Vienna, Dunn Loring and Merrifield to use boiled tap water or for drinking or cooking as a precaution.

Jeremy Borden, Emma Brown, Mike DeBonis, Margaret Ely, Anita Kumar, Luz Lazo, Annys Shin, Donna St. George, Joe Stephens, Patricia Sullivan, Tom Jackman, Ted Trautman, John Wagner and Mihir Zaveri contributed to this report.