Estimated damage from Sunday’s earthquake in Napa County has reached at least $300 million, and county supervisors are preparing to petition the federal government for help, local officials said Wednesday.

The economic toll of the magnitude-6.0 quake is expected to climb significantly when officials factor in government buildings, public infrastructure, personal belongings, destroyed business inventory and lost business.

The $300 million estimate is limited to structural damage to homes and commercial properties, and only those in the city of Napa, the city’s public information officer, Barry Martin, said.

“We’re just getting started. This number is only going to go up,” Martin said.

No damage estimates had been issued yet for unincorporated Napa County, though officials were working on one, spokeswoman Molly Rattigan said.

The Board of Supervisors nonetheless had scheduled a special 1 p.m. session to begin the process of seeking a federal declaration of emergency entitling some quake victims to seek recovery assistance.

Board Chairman Mark Luce warned that federal aid would not be enough to provide for the county’s recovery, however.

“This will help some in need, but will only be part of what is needed,” Luce said in a written statement. “We are looking for both government and nongovernment support to aid in our recovery.”

Sunday’s early-morning quake, centered 4 miles northwest of American Canyon, struck all of Napa County hard, but particularly its largest city, injuring more than 200 people and damaging more than 650 buildings around the county, most of them in the city of Napa.

Virtually everyone suffered some loss, even if it was only dishes falling off of a shelf, Martin said.

And yet, many in the city of 77,000 escaped serious damage, and there were signs Wednesday that folks were beginning to snap out of the daze and disbelief that came with the initial shock of the temblor, he said.

About 90 percent of the restaurants in the hardest-hit downtown area were operating, Martin said, as were many, if not most, hotels around the county, Rattigan said.

“By Tuesday, a lot of people were shifting into, ‘OK, now I’ve got to knuckle down and get back to work here and get things back in order,’ ” Martin said. “Today it was definitely more of a regular-feeling-almost kind of day.”

For those hit hard, it would be some time before any semblance of normalcy returned, however, and hundreds of homes and businesses — though fewer than 500 — remained without water Wednesday.

At least 132 buildings, all but 16 inside city limits, were deemed unsafe to enter and had been red-tagged, officials said. Yellow tags, advising caution, had been applied to 534 structures, again most in Napa.

Martin said the city still was trying to get a handle on how many people had been displaced from their homes by the earthquake.

Building inspectors in lime-green vests continued to swarm the streets Wednesday, examining cracks and other damage to structures downtown.

The streets also buzzed with workers loading up broken TVs, crushed furniture and other debris from the quake onto large garbage trucks to be hauled off.

So much debris was being dumped at local schools that the city removed disposal boxes from the campus sites and directed residents instead to deliver waste to three other locations: a future fire station site on First Street, the Las Flores Community Center and a vacant lot on Third Street.

Silvia Guzman, who lives in west Napa, said she and her family were among those still without water.

She said she’s had to make daily trips to one of the city’s two water-dispensing sites, this one outside Las Flores Community Center, where her three kids helped fill large buckets and load them into the back of the family’s minivan.

“It’s been hard,” Guzman said about driving more than a mile each way to fetch water to wash dishes and flush their toilets.

Napa Valley College had opened its locker rooms and showers to those without water or displaced from homes, city officials said.

Officials hoped to have water service restored to everyone in the city by Friday, with the idea that the three-day Labor Day weekend might offer a respite to quake victims and workers alike, Martin said.

The plan by Tuesday is to launch fully into recovery mode, in part through a local assistance center planned by city and county staffers to serve as “a one-stop shop” for those requiring all manner of earthquake help — including housing, food, building inspections and permits, and help applying for aid, Martin said. The location of that center still is being determined.

“If you have a problem related to the earthquake, someone will be here to help you,” he said.

Today’s special supervisors meeting will be held at the Napa County Transportation and Planning Agency at 625 Burnell St., Napa.

Staff Writer Eloí sa Ruano Gonzá lez contributed to this report. You can reach Staff Writer Randi Rossmann at 521-5412 or randi.rossmann@pressdemocrat.com and Staff Writer Mary Callahan at 521-5249 or mary.callahan@pressdemocrat.com.