In an unprecedented move to slow the spread of an illness killing people throughout the world, six Bay Area counties on Monday issued a legal order directing their residents to stay at home for three weeks starting Tuesday.

The order affects nearly 7 million people and limits activity, travel and business functions to only the most essential needs. The counties that issued the order are: Alameda, Contra Costa, Marin, San Francisco, San Mateo, and Santa Clara counties announced, and the City of Berkeley which has its own public health division. Santa Cruz County also issued a similar mandate asking residents to shelter in place.

Related: California Gov. Newsom calls for home isolation for all seniors

“Temporarily changing our routine is absolutely necessary to slow the spread of this pandemic,” said Dr. Sara Cody, Santa Clara County's public health officer. “The health officers from the largest jurisdictions in the San Francisco Bay Area are united and we are taking this step together to offer the best protection to our respective communities."

Related: Bay Area school districts offering free meals during closures


As of Sunday, there were more than 258 confirmed cases of coronavirus and four deaths within these seven jurisdictions.

The order defines essential activities as necessary for the health and safety of individuals and their families.

Don't forget to download the new and improved KTVU mobile app

Essential businesses allowed to operate during the recommended action include health care operations; businesses that provide food, shelter, and social services, and other necessities of life for economically disadvantaged or otherwise needy people; fresh and nonperishable food retailers including convenience stores; pharmacies; child care facilities; gas stations; banks; laundry businesses.

In addition, sanitation, health care, police, emergency responders, and essential government functions will continue under the recommended action. And San Francisco officials said it's still OK to take the dog for a walk or to go on a hike, as long as you walk six feet apart from someone.

San Francisco Public Health Director Dr. Grant Colfax said, "With this order in place you will still be able to get food, care for relatives, run necessary errands and conduct the essential parts of your lives."

Bay Area residents are still able to take public transportation like BART, Muni, and the San Francisco Bay Ferry, so long as it's for essential purposes.

As laid out by Alameda County, those who are experiencing homelessness are exempt from the order, but governmental entities are urged to make shelter available as soon as possible.

Oakland Mayor Libby Schaaf said on Monday she recognizes that homeless people are particularly vulnerable to contracting COVID-19 and said city services are finding new shelters for those who are ill.

"They have already secured additional places where we can bring unsheltered people indoors who do need to be put under medical quarantine," she said.

At a news conference in San Francisco, Mayor London Breed assured her citizens that police services would still be up and running and she urged people not to feel panicked.

Still, she said, these measures are being enacted through April 7 to slow the spread of community contact of the virus, which has no vaccine or cure. However, health leaders said as COVID-19 runs its course, they could loosen the restriction or institute more measures to protect the public's health.

"We know that there will be more that we need to do," she said.

Officers will be patrolling with the aim primarily of educating, but enforcing if necessary.

San Francisco Police Chief Bill Scott said, "We're asking the public to voluntarily comply. Now, this order, by law, is enforceable as a misdemeanor for failure to comply with it. But that is an absolute last resort."

Across the country, the White House on Monday recommended that older people and those with underlying health conditions "stay home and away from other people" as it continues to step up efforts to halt the spread of the novel coronavirus pandemic. California's governor issued that same sentiment on Sunday.

MORE CORONAVIRUS COVERAGE:

Fact or fiction: Your coronavirus questions answered

Why is your toilet paper vanishing?

Feds take emergency measures, slash rates and ease rules