Smell Gas? What to Do in a Phoenix-Area Home

The first two minutes

1. Get out. Take people and pets and leave. Do not stop to look for the source or open every window.
2. Do not make a spark. Southwest Gas warns against using electronics, matches, lighters or anything that could cause a spark. That includes light switches, the garage door opener, doorbells and starting a car parked in the garage.
3. Call from a safe distance. Once you are well away from the house, call 911 and the gas utility. Southwest Gas asks for both calls, at 877-860-6020, whether or not you are a Southwest Gas customer.
4. Keep others back. Wait outside, away from the building, and keep neighbors and kids clear.
5. Stay out until cleared. Go back in only when firefighters or the utility tell you it is safe.

Leaving first matters more than anything else on this page. A strong odor, a hissing sound or someone feeling dizzy or ill are all reasons to go now and sort out the cause later.

Which gas utility do you call?

Southwest Gas serves the City of Phoenix and much of the valley, but not every home is on it.

The City of Mesa's gas system also reaches some addresses in Queen Creek, San Tan Valley and other parts of Pinal County. If you are not sure who supplies your gas, the utility's name is on your gas bill. Saving its emergency number in your phone now saves a search later.

How to recognize a gas leak

Natural gas has no smell on its own. Utilities add an odorant called mercaptan, which Southwest Gas describes as a strong sulfur-like odor, similar to rotten eggs. The utility lists other signs too:

• Sound: hissing or roaring near the ground or near a gas appliance
• Sight outdoors: dirt blowing around, bubbling in standing water, or plants that have died or discolored near a pipeline or meter

In a desert yard, a patch of dead plants along the line to a pool heater, grill or fire pit is easy to blame on summer heat. If it sits right over a gas run, treat it as a possible leak.

Is it gas or something else?

Other things can smell like rotten eggs. When you are unsure, leave and call anyway; responders would rather check a false alarm. Two common look-alikes:

Rotten-egg smell only from the hot water

If the odor shows up only when you run hot water at a faucet, and the cold side smells fine, the water heater is the likely source. Corro-Protec, a maker of anode rods, explains that the rod in a tank heater can react with sulfates in the water and that bacteria in the warm tank can produce hydrogen sulfide. That is a water quality issue rather than an emergency; water heater repair covers flushing the tank and swapping the anode. Note that the manufacturer warns against simply pulling the rod out, since it is the tank's protection against rust.

Sewer odor from a drain

A sewer smell is usually closer to rot than to sulfur and tends to come from a single drain, often one that is rarely used, such as a guest shower or floor drain where the trap has dried out in summer heat. Running water into it often clears the smell. If it keeps coming back, have the vent and drain lines checked as part of clearing the household drains.

Who fixes what after the utility arrives?

The gas utility responds to the emergency, finds whether gas is escaping, and makes the situation safe. If the leak is in the house piping or an appliance, the responder may shut off the gas to that appliance or to the whole house and leave the repair to you.

Ownership is split at the meter. Southwest Gas owns and maintains the piping up to and including the meter. Everything after it, including buried pipe running from the meter to the house and out to a pool heater, grill or fire pit, belongs to the property owner. Southwest Gas tells owners to periodically inspect those lines for leaks and corrosion, to repair any unsafe condition right away, and to get help locating and inspecting buried piping from a leak detection company or a plumber. It also says an owner can pay to have the meter moved next to the house, which shortens the buried pipe the owner is responsible for.

That house-side piping is where a plumber's gas line repair and installation work comes in: finding the leak, replacing a corroded section or a cracked appliance connector, and pressure testing the system before the utility turns gas back on. City of Phoenix Planning and Development lists Repair/Replace Gas Line among its residential online permits; ask the plumber who pulls the permit and schedules the inspection. Historic-district properties go through the regular permit process instead.

If you use propane

Homes on the edges of the metro, from New River to rural parts of Pinal County, may run on a propane tank instead of utility gas. Propane industry guidance follows the same order: eliminate ignition sources, get everyone out, and, only if it is safe to do so, shut off the main valve on the tank by turning it clockwise. Then report the leak from a safe place, such as a neighbor's house, to your propane retailer, or to 911 or the fire department if you cannot reach the retailer. Stay away until a responder or qualified technician says it is safe, and have the system checked for leaks before relighting any propane appliances.

Digging near gas lines

Many gas leaks start with a shovel. Southwest Gas asks anyone planning a digging project, of any size, to call 811 first so utility lines get marked. Remember that 811 marks utility-owned lines; private lines a past owner ran to a grill or fire pit may not be on any map, so the Southwest Gas buried-pipe guidance says to hand dig near buried gas piping. Plan for this before any landscaping, pool, patio or water line repair work that opens up the yard.

Preventing the next scare

• Know where your meter is and keep the area around it clear
• Replace old flexible appliance connectors when you swap a range, dryer or water heater
• Have new outdoor gas lines pressure tested and inspected under permit
• Make sure a tankless conversion includes a check of gas pipe sizing; our tankless and tank heater comparison explains why the load matters
• Walk buried gas runs now and then and watch for dead plants or bubbling water

Not sure whether something can wait until morning? Our guide on deciding between an emergency call and waiting covers other urgent problems. A suspected gas leak is never one to wait on: leave, call 911 and the utility, and line up a plumber for the repair once the house is safe. For other urgent situations, local plumbers also handle after-hours plumbing emergencies in Phoenix.