Plumbing Checks After an Earthquake

What should you check first after an earthquake?

Check for gas first. If you smell gas or hear a blowing or hissing sound, Ready.gov says to open a window, get everyone out, turn off the gas at the outside main valve if you can, and call the gas company from outside or a neighbor's home; call 911 for fire or injuries.

SoCalGas's emergency page adds the how: the shutoff is on the riser about 6 to 8 inches above the ground, and a 12-inch or larger adjustable wrench turns it a quarter turn until it sits crosswise to the pipe. FEMA P-530 says a rapidly spinning gas meter is also a sign of a leak. Until you are sure there is no leak, Glendale's fire department warns against open flames and anything electrical that could spark.

If you smell nothing, leave the gas on. Once the meter valve is closed, only SoCalGas or its certified contractors may open it again, and after a big quake that can take days or weeks. A house with a seismic gas shutoff valve may already have closed itself.

How do you check the water heater after a quake?

Look at the water heater second, because it carries both gas and water. NIST's report on the 1994 earthquake noted that inadequately secured water heaters "are likely to tip over," and that a destroyed multifamily building's fire was reported to have started with water heater damage.

Check that the tank is upright and has not shifted, that both straps are still tight to the wall, and that the gas line and water connectors are intact. California requires every residential water heater to be braced, anchored or strapped (Health and Safety Code § 19211), and the 2025 California Plumbing Code puts the straps in the upper and lower thirds of the tank, the lower one at least 4 inches above the controls (§ 507.2). The water heater straps page explains the rule.

If the heater moved, the vent pipe on top is loose, or you smell gas near it, leave its gas off and have a licensed plumber (C-36) or SoCalGas inspect it before relighting. If the tank is leaking, close the cold water valve at its top or the main water shutoff.

How do you spot hidden leaks after shaking?

Use the water meter. With every faucet, appliance and irrigation valve off, read the meter, wait 15 minutes, and read it again; San Fernando's city water report for 2025 says any movement means a leak. EPA WaterSense gives a slower version: no water use for two hours, and any change on the dial points to a leak.

Then walk the house. Look for damp drywall, warm or wet spots on a slab floor, water around the water heater and toilets, and soggy ground along the line from the meter to the house. Shaking can crack old joints in walls and under slabs where nothing shows for days, which is why the hidden leak checks and the notes on slab leaks are worth a read.

A leak on the house side of the meter is the owner's to fix. One between the street and the meter belongs to the utility, so report it to whichever of LADWP, BWP or GWP bills you.

Is it safe to flush toilets after an earthquake?

Not until local officials say the sewers are working. Oregon State University Extension's sanitation publication EM 9334 (2021) puts it plainly: "Avoid using toilets even if your home sewer lines are not damaged," because pipes in the street may be broken (OSU Extension). The City of Los Angeles's Earthquake Annex has LA Sanitation assess sewer flow and pumping after a quake, so watch local news and emergency alerts for word on the sewers, as Ready.gov advises for all post-quake instructions.

Until then, line the toilet bowl or a bucket with heavy garbage bags; Ready.gov's kit list includes bags and plastic ties for personal sanitation, and OSU recommends a two-bucket system that keeps urine and solids apart. In Los Angeles the owner is responsible for the sewer lateral from the house to the city main, so a backup that starts at your cleanout is a private repair; see who owns the sewer lateral.

When is tap water unsafe after a quake?

Treat tap water as unsafe whenever your utility or the city says so, and whenever pressure has dropped or the water looks cloudy or smells wrong. Ready.gov notes that cracked lines may pollute the supply to your house and suggests keeping the main shut until authorities say the water is safe to drink, and OSU Extension notes that health officials may call for boiling after a loss of pressure.

Listen for notices: LA Emergency Management's kit checklist suggests a battery or crank radio tuned to AM 1070 for emergency alerts. Under a boil-water notice, boil water hard for a full minute, or use stored water and the bleach doses on the emergency water storage page. Once the notice lifts, run the cold taps for a few minutes before drinking; the tap water safety page covers normal-day quality.

What did Northridge teach about plumbing after an earthquake?

Northridge taught that the gas and water lines under a city fail by the hundreds, and that households make the recovery slower or faster. NIST's fire study counted about 110 quake-related fires, roughly 1,400 breaks and leaks across LADWP's pipes, and hydrants without pressure across much of the west and north Valley.

It also found that most of the 151,000 gas outages came from customers closing their own valves, and NIST's 1994 report explained the cost: technicians had to test each system before turning service back on. Shutting gas only for a real leak, keeping water heaters strapped, and knowing your water shutoff are the three habits that would have helped most.