By William Rodarmor

If you live in the San Francisco Bay area, you can probably recite in your sleep a list of steps to prepare yourself for the next earthquake: bolt the foundation, strap the water heater, buy spare food and water, etc. But one item on the list has generated enough controversy to deserve an article of its own: the automatic gas shutoff valve.

As a result of the 1994 Northridge quake, Los Angeles and some other communities (Brentwood, for example) now require shutoff valves on all homes built, sold, or remodeled. Alameda, Contra Costa, and Marin counties have passed similar ordinancesæmainly for new construction and big remodelsæas have the cities of Pittsburgh and Hercules. But proposed statewide legislation hasn’t passed, and PG&E is officially neutral on the devices.

The basic idea is simple: install a device that automatically turns off the flow of gas to your house when the ground starts to shake. After all, leaks from broken gas lines can cause fires, reducing your shaken home to ashes. But the usefulness of automatic shutoff valves is a topic of hot debate, which makes it hard for homeowners to decide whether to get one.

A major proponent of shutoff valves is Dan Szumski, a Davis civil engineer and structural design consultant who has long worked in the East Bay. “Bolting your house down is number one on my list,” he says. “Getting an earthquake-activated shutoff valve is number two.”

It doesn’t take a very large earthquake to break a gas line, says Szumski. “If you have a furnace in your basement, it can shoot to the other side of the room. The stove in the kitchen can pull away from the wall and start filling the house with gas.”

Szumski, who has studied hundreds of East Bay houses, says he never saw a shutoff valve in 1989, when the Loma Prieta quake hit; now he sees one every week or so. He says that the valves will come into their own when the Big One hits. “There were several fires during the Loma Prieta earthquake,” he says, “and that was a tiny quake compared to those that hit along the Hayward Fault in the 1860s.”

PG&E takes a different approach, preferring to shut off the gas to a neighborhood from a central location. “But that leaves a lot of gas in the system,” says Szumski, “and at 8 to 10 pounds of pressure, most of it will be dissipated in houses.”

Szumski says that the valves aren’t being much used in new local construction, and is concerned that East Bay officials haven’t mandated their wider use. “A lot of our houses are very close together, and if one burns, so will the others,” he says. “As an engineer, I’m responsible for public safety. Seismic safety is one of the biggest components of a house’s design, and I don’t think it’s complete unless you’ve included a gas shutoff valve.”

Pacific Gas & Electric is officially valve-neutral. “Everyone needs to make the determination whether this device is best for them,” says Jason Alderman, a PG&E media representative. “But if you decide to install one, it’s very important to have a licensed plumber do the installation. Don’t buy any do-it-yourself kits or videos, and make sure the plumber installs it on the homeowner side of the meter. If it gets installed on the PG&E side of the meter, we’ll ask you to move it, at an additional expense.”

Alderman also urges calm in minor quakes, because people sometimes turn off the gas when they don’t need to “They have memories of flames shooting in the air from the Loma Prieta earthquake,” he says, “so when they feel a rumble underground, they yank off the gas. We don’t recommend that people do that.” If you smell or hear gas, and think there’s an imminent risk of danger, turn your gas off, he says; otherwise, be judicious. “We’ll come and relight your pilot lights, but it won’t be instantaneous, and the delay can be very inconvenient.”

PG&E may not have a formal position on shutoff valves, but one of its staffersæa well-informed North Berkeley homeowner I’ll call Lindaæthinks they’re pointless. “I can understand why people might be drawn to them,” she says. “If a quake hits when you aren’t at home, or it’s the middle of the night where there could be pandemonium, the valves seem to offer peace of mind. But we see no evidence that they do what they promise,” she says.

“They’re expensive, they don’t offer a lot of value, they could damage the gas system, and they give a false sense of security. There are a lot of people taking advantage of folks’ fears by offering a seemingly rational-sounding device,” says Linda.

“It makes much more sense to spend six bucks on a crescent wrench and keep it next to the meter,” she says. "And if you’re worried that nobody’s going to be around, have a community meeting and make sure that everybody gets wrenches. That way, if something horrible happens, whoever is home can go around the neighborhood and turn the valves off.”

That we live in earthquake country isn’t exactly news, but the borders of that country just became clearer. The California Geological Survey has officially released Seismic Hazard Zone maps covering Alameda, Albany, Berkeley, Emeryville, Oakland, Piedmont, and San Leandro. Preliminary maps are available for Hayward and Newark; mapping of the Richmond, Briones Valley, and Las Trampas Ridge quadrangles is underway.

The maps identify areas that are prone to liquefaction and earthquake-induced landslides. Created under the Seismic Hazards Mapping Act of 1990, they help cities and counties determine whether proposed construction lies in potentially hazardous areas, and decide whether further investigations must be done at the owner or developer's expense. When selling, the owner must disclose that a property is in a hazard zone.

To see and download the maps, go to the California Geological Survey’s website. Slide areas on the hills appear in pink, and a honey-colored liquefaction zone laps at the shoreline and the flats. No (or slow) Internet access? The maps are also on display at various places, including local libraries.

The Internet is by far the easiest place to find useful information on how to deal with an earthquake or other disaster. Here are two sites among many with lists of steps you can take: The Hodgeshill Herald and LAFD Earthquake Preparedness Handbook.

William Rodarmor is a freelance writer, editor, and French translator in Berkeley, CA