Attention, travelers going to or through San Francisco: Bring your own water bottles.

The city’s airport is banning the sale of plastic water bottles as of Aug. 20 in the name of sustainability, urging thirsty fliers to bring reusable water bottles to fill at water stations around the airport.

If you don’t have a bottle in your backpack when you arrive at San Francisco International Airport, you’ll have a few options: search out water being sold in aluminum, glass, or compostable packaging; buy a flavored or sugary beverage (still available in plastic); or purchase a reusable bottle to fill.

The new rule is part of the airport’s zero-waste plan “to reduce the airport’s impact on the environment,” according to its website. In 2014, San Francisco began phasing out the sale and distribution of plastic water bottles on city-owned properties.

A spokesperson for the airport told the San Francisco Chronicle that SFO is the first airport to institute such a plastic bottle ban.

There is no chance the idea will be replicated at Philadelphia International Airport — at least not for a year. In June, Gov. Wolf signed a measure — slipped in as an amendment to part of the state’s $34 billion budget deal — prohibiting any municipality from banning plastic bags, bottles, or other single-use receptacles for one year to give the state more time to study the issue.

But PHL “is actively working to reduce its plastic bottle offerings while exploring methods to increase the use of plastic-free reusable bottles” and has implemented a “robust” recycling program, spokesperson Florence Brown said Friday.

The state’s ban on bans came after legislators in Harrisburg offered a package of zero-waste bills this spring and received pushback from plastics interests. The package included bills for banning plastic and foam take-out containers, plastic straws, and plastic bags; one measure sought to require water-bottle filling stations in new or renovated state buildings.

The prohibition would at least delay a proposal to ban plastic bags introduced in Philadelphia City Council less than two weeks before Wolf signed the bill. Last month, a bag ban was passed anyway in West Chester, the borough council members defying the state law (though they amended it to go into effect in a year, after the state’s prohibition expires).

California — and San Francisco in particular — has pushed to be at the forefront of phasing out single-use plastics. Plastic bags are outlawed statewide, and plastic straws are available only by request at restaurants; the progressive city has more expansive restrictions on plastic dining items.

Seven direct flights depart Philadelphia for San Francisco each day, Brown said. If you bring your own bottle, you can fill it at one of the 50 filling stations throughout the airport. At SFO, hydration stations supply tap water in all boarding areas.