Seattle gun owners could soon face fines or community service for failing to safely store their firearms.

The Seattle City Council passed a bill Monday to mandate safe gun storage and create new civil infractions for those who fail to comply. The new law will allow fines of up to $500 for people who fail to safely store their guns.

Penalties could escalate from there.

The bill creates civil infractions for both failing to safely store a gun and failing to safely store a gun when the owner "knows or reasonably should know" that the gun could be accessed by a minor, a person who's legally not allowed to possess guns, or someone who is "at risk." ("At-risk" is defined as someone who has "made statements or exhibited behavior that indicates to a reasonable person there is a likelihood that the person is at risk of attempting suicide or causing physical harm to oneself or others.")

If a minor, at-risk person, or person not legally allowed to possess a firearm accesses a gun that was not safely stored, the owner could face a fine of up to $1,000. If the person access the gun and uses it in connection with a crime or to kill or injure someone, the owner could face a fine of up to $10,000.

If the gun is used in a mass shooting, courts would have the ability to levy more than one $10,000 fine against the gun owner. Courts could consider restitution in lieu of fines.

The council also approved changes to an existing law about reporting lost or stolen firearms. Fines for failing to report will increase from $500 to $1,000.

Supporters of the legislation said it is meant to reduce accidental gun injuries, thefts, and suicides. Research shows that the presence of household guns is associated with a higher risk of suicide and that keeping guns unloaded and locked up can help prevent accidental injuries and some suicides.

Yet, most gun owners don't store their guns locked up and unloaded. According to the legislation, 150,000 people in King County reported keeping a gun unlocked in their homes in 2015. Research released this year by the University of Washington School of Public Health found that about 34 percent of Washington adults had a firearm in their household and only 37 percent of those stored the gun unloaded and locked.

Mayor Jenny Durkan originally proposed the legislation approved by the council. In a statement Monday, she called it “the kind of action we need to save lives.”

“Requiring that gun owners responsibly store their guns can help make our communities safer places to live,” Durkan said.

It remains unclear exactly how—or how strictly—Seattle will enforce the new law. While officers may receive tips about unsafely stored guns, a representative for Durkan said during a council committee meeting that the city would focus on education before enforcement.

Robert Feldstein, a staffer in the mayor’s office, told council members police would likely become aware of improperly stored guns through other law enforcement actions at first. “After there’s been an established track record of education and opportunity to comply, we will start addressing the ones where all we know is that there’s an unsecured [gun],” Feldstein said.

“Except for in the most egregious cases,” Feldstein added later, “my guess is for the first extended period—at least year—will be really emphasizing education and ‘here’s the consequences, you should know.’”

When she announced the legislation in March, Durkan said, “We won't be going into homes.”

State law prevents local officials from passing more dramatic gun safety measures. Washington law bans cities from regulating the “registration, licensing, possession, purchase, sale, acquisition, transfer, discharge, and transportation of firearms, or any other element relating to firearms or parts thereof, including ammunition and reloader components.”

In 2015, the Seattle City Council passed a law to tax guns and ammunition sold in the City of Seattle. The law faced legal challenges from gun rights advocates including the National Rifle Association, who argued it violated the state preemption law. The Washington State Supreme Court upheld the tax last year.

The enforcement section of the new safe storage law will take effect in about six months. Through a rule-making process, the Seattle Police Department will define what exactly constitutes safe storage.