How to Prepare Your Plumbing for Bay Area Earthquakes

The Bay Area experiences thousands of small earthquakes every year, and the USGS estimates a 72 percent probability of a magnitude 6.7 or greater earthquake striking the region before 2043. The Hayward Fault runs directly through the East Bay, and the San Andreas Fault parallels the Peninsula.

When a significant earthquake hits, plumbing systems are among the most vulnerable parts of a home. Water heaters topple, gas lines rupture, supply pipes crack, and sewer lines shift. The good news is that most earthquake-related plumbing damage is preventable with a few straightforward preparations that cost far less than post-earthquake repairs.

California law requires all water heaters to be secured with two metal straps, one in the upper third and one in the lower third of the tank, anchored to the wall studs behind the unit. An unsecured water heater can tip during an earthquake, rupturing the gas line and water connections. A 50-gallon tank weighs over 400 pounds when full.

If your water heater was installed before 1996 or by a previous homeowner, check the strapping. Many homes in San Jose, Sunnyvale, Mountain View, and throughout the South Bay have water heaters that are either unstrapped or strapped with outdated single-strap kits that do not meet current code.

A licensed plumber can install proper seismic strapping in under an hour. If you are getting a water heater replaced, strapping is included as part of any code-compliant installation.

Rigid gas connections (hard black iron pipe running directly from the wall to the appliance) are vulnerable to cracking during earthquake movement. Modern building code requires flexible gas connectors, which are corrugated stainless steel lines that can flex without breaking.

Check every gas appliance in your home: water heater, furnace, stove, and dryer. If any are connected with rigid pipe, have a licensed plumber replace them with approved flexible connectors. This is one of the least expensive and most effective earthquake preparations you can make, typically $75 to $150 per appliance.

After an earthquake, broken water pipes inside walls or under the slab can flood your home in minutes. Knowing exactly where your main water shutoff is and being able to turn it off quickly is essential.

For most South Bay homes, the main shutoff is either at the water meter near the street (requires a meter key to operate) or on the supply line where it enters the house, usually near the garage or front of the home. Find yours now, test it to make sure it turns, and keep a meter key accessible if your shutoff is at the street.

After any earthquake strong enough to knock items off shelves, shut off the water main as a precaution and visually inspect all visible supply lines before turning it back on. A cracked pipe inside a wall can leak for hours before you notice water damage.

An earthquake shutoff valve (also called a seismic gas shutoff valve) automatically cuts gas flow when it detects significant ground motion. It installs on the gas meter and activates without any action on your part. After it triggers, a licensed plumber or PG&E must reset it manually, which ensures someone inspects for damage before gas is restored.

These valves cost $200 to $500 installed and are required by code in some California cities for new construction and major remodels. Even where not required, they are one of the most effective safety upgrades for any South Bay home, especially older homes in San Jose, Campbell, and Santa Clara where gas infrastructure has aged.

If you smell gas after an earthquake, leave immediately. Do not flip any switches or use your phone inside the house. Call PG&E from outside at 1-800-743-5000.

If there is no gas smell, do a visual inspection before using any water. Check under every sink for dripping or pooling water. Look at the water heater for leaning, disconnected pipes, or water on the floor. Check toilets for cracks in the tank or bowl. Look at exposed pipes in the garage, basement, or crawl space for obvious breaks.

If you find damage, shut off the water main and call a licensed plumber. Even small cracks in supply lines can worsen with aftershocks. Do not use the sewer system until you are confident the main line is intact. A plumber with a sewer camera can verify this quickly.

After a major earthquake, municipal water service may be disrupted for days. FEMA recommends storing one gallon of water per person per day for at least three days. For a family of four, that is 12 gallons minimum.

Your water heater tank is also an emergency water source. A standard 50-gallon tank holds enough water for a family of four for over a week. To access it safely after an earthquake: turn off the gas or electricity to the unit, let the water cool, then open the drain valve at the bottom of the tank with a bucket underneath. This water is safe for drinking as long as the tank was intact.

Arcune Plumbing helps South Bay homeowners prepare their plumbing systems for earthquakes. We install seismic water heater strapping, flexible gas connectors, earthquake shutoff valves, and perform full plumbing safety inspections. We serve San Jose, Santa Clara, Sunnyvale, Mountain View, Cupertino, Campbell, Los Altos, Palo Alto, Milpitas, and Portola Valley.

Do not wait until after an earthquake to discover your water heater was not strapped or your gas connections were rigid. Call us at (650) 787-7061 to schedule an earthquake readiness inspection. It is one of the best investments you can make for your home and your family's safety.