How do I turn off the gas to my house?

You shut it off with a quarter turn of the meter valve. The Department of Energy's Building America Solution Center, run by Pacific Northwest National Laboratory, lays out the steps that utilities give homeowners:

1. 1Find the valve. "It is typically next to the gas meter." In a Phoenix house the meter is usually on an outside wall, and the valve is on the vertical pipe coming out of the ground just before the meter.
2. 2Use the right wrench. "Keep a 12- to 15-inch adjustable pipe or crescent-type wrench in a known location." The guide adds that it "may not be advisable to keep it visible next to the meter where someone might use it to tamper with the meter."
3. 3Turn it a quarter turn. "Give the valve a quarter turn in either direction. The valve is closed when the tang (the part of the valve you put the wrench on) is crosswise (perpendicular) to the pipe."

When the valve is open, the tab lines up with the pipe. When it's closed, the tab forms a cross with it. These valves can be stiff, which is why the guide calls for a long wrench. Don't use a hammer on it or force it with a cheater bar. If it won't move, stop and call Southwest Gas.

Not before you leave. In Southwest Gas territory, the steps for a suspected leak start with getting out: "Exit the area or building immediately. Tell others to evacuate and leave doors open." Then, "From a safe place, call 911 and Southwest Gas at 877-860-6020, day or night." Its safety page also says not to operate "any electric switches, thermostats, or appliance controls, or do anything that could cause a spark."

The DOE guide gives the other side of the rule, from the utilities it surveyed: "Do not shut off the gas unless you smell gas, hear gas escaping, see a broken gas line, suspect a gas leak, or are advised to do so by the gas utility. If you shut off the gas, there may be a considerable delay before the utility can turn your service back on."

Put together, that works out to:

• Strong smell inside, or hissing: get everyone out and call. Don't go back in for anything.
• Southwest Gas tells you to shut it off: do it, if you can reach the meter safely from outside.
• Broken or damaged line outside, like after digging: move away, keep people back, and call 911 and Southwest Gas.
• No leak, just planned work: have the plumber handle it as part of the job.

Close the appliance valve when the problem is one appliance. The fuel gas code Phoenix uses requires each appliance to have its own shutoff valve, "in the same room as the appliance" and "within 6 feet (1829 mm) of the appliance." For a range or a dryer, a valve behind the appliance counts as accessible.

The DOE guide explains the benefit: "If a leak happens at a specific appliance, the valve allows you to turn off the natural gas at the appliance rather than shutting off the natural gas service line to the whole house." It adds that "Some valves require a wrench."

Common cases where the appliance valve is the right one:

• Replacing or moving a dryer or range, where the connector gets disconnected.
• A water heater that needs service. Manufacturer instructions also have their own steps; A.O. Smith's label says to turn the gas control knob to "OFF" to turn off gas to the appliance.
• A pool heater or grill line that won't be used for a while.

Most appliance valves are also quarter-turn: handle in line with the pipe is open, crosswise is closed. This keeps the water heater and furnace running while one appliance is off.

Southwest Gas turns the gas back on at the meter, not the homeowner and not a plumber. Its Arizona tariff says only its "duly authorized employees or agents" can turn on the utility's supply of gas, and service is restored only after the utility's leak check. The tariff also says that if uncontrolled leakage exists at turn-on, service will be denied.

The DOE guide gives the same advice from utilities across the country: "Do not turn your gas back on if it has been turned off at the meter. Call for a gas utility technician to come out," and "Let the gas company's service technician check the equipment, open the gas line, and re-light pilot lights."

What happens next depends on why the gas was off:

• Turned off for a leak or a repair. In Phoenix, repairs where the gas was shut off at the building, and a meter locked by Southwest Gas for a leak on the customer side, need a city permit, a city inspection, and a city gas clearance before the gas comes back, according to the gas clearance table the city published with Southwest Gas and the Arizona Corporation Commission.
• Turned off as a precaution, with no work done. Southwest Gas restores service and checks for leaks. Call 877-860-6020 to schedule.

Plan for someone to be home, since the technician needs to reach every gas appliance to relight it.

### What about automatic shutoff valves?

Some homes have them, and they're a different thing from the meter valve. Southwest Gas explains that an excess flow valve "automatically closes and restricts the flow of natural gas if a service line is broken," and that it has installed them "on most residences built after June 2008." It also lists what an EFV won't catch: "customer appliance malfunction, customer houseline gas leaks, small punctures in the underground pipe, or gas meter leaks."

A seismic shutoff valve is optional and bought by the owner. Southwest Gas says that if one closes, "contact a licensed, qualified contractor to reset the valve, verify that no gas leaks exist, and perform a safety check of your gas appliances before they're placed back into operation."

HQ Plumbing & Air repairs gas lines and appliance shutoff valves across the Phoenix area, including adding a valve where an appliance doesn't have one. See our gas line service, and our page on what to do when the house smells like gas.

Quarter turn, crosswise, off. Southwest Gas turns it back on.