Menlo Park is expected to sign off Tuesday on a plastic bag ban, joining the ranks of other cities and counties who have already done so, making the Bay Area the most active region in a statewide movement to do away with the bags. 

The action is one piece of San Mateo County's coordinated plan, as plastic bags are one of the leading sources of litter in the county's storm drains and creeks. When bags aren’t clogging the waterways, they’re flowing down them, sickening animals that mistake them for food.

Other cities across San Mateo County are considering banning plastic bags at all retail outlets and requiring consumers to pay at least 10 cents for a take-out paper bag.

Nick Sharma owns the Willows Grocery store in Menlo Park,and he says that customers are expecting the change. "They’re like, 'Hey what’s the hold up?' " Sharma says. "They know about the ban in San Jose and across the bay. People are already using reusable bags. I’m a little surprised it’s taking this long."

The San Mateo county board has already banned single-use plastic bags at retail check-out counters in unincorporated communities.  That ordinance is expected to take effect on April 22: Earth Day.