Plenty of people in Tacoma still remember the morning of February 28, 2001. The Nisqually earthquake rolled through at magnitude 6.8, and because it began deep underground, the damage was scattered rather than total. Chimneys toppled and old brick cracked. In basements and garages across the South Sound, water heaters slid away from walls, snapped their supply lines, and soaked floors while their owners were still standing in doorways.
Ask a licensed local tradesperson like Anthony The Plumber about earthquake prep and the talk usually starts with the tank in the garage and the lines feeding it. The Tacoma outfit works from South Baltimore Street and spends much of its week on water heater installs, pipe replacement and water line repair. Those happen to be the exact parts of a house that shift, crack or leak when the ground moves.
The Ground Under Tacoma Has a Long Memory
Washington carries the second highest risk of large earthquakes in the country, and the South Sound sits near all three kinds. There is the Cascadia Subduction Zone offshore, capable of a very long and violent rupture. There are deep quakes like Nisqually, which shake a wide area at moderate strength. And there are shallow crustal faults, including the Tacoma Fault, which runs beneath the city and the Narrows and is linked by geologists to a large quake roughly a thousand years ago.
Soil matters as much as the fault. Homes on the Tideflats, along the Puyallup River valley, or on old fill near the water sit on ground that can lose strength and settle during strong shaking. The Washington Geological Survey publishes maps of active faults and liquefaction zones, and it’s worth five minutes to see where your street falls. A house on glacial till up on the hill will move differently than one near the port, and the plumbing inside feels that difference.
The Heaviest Thing Standing Upright in Your Home
A full 50 gallon tank holds more than 400 pounds of water before you count the steel. It’s tall, narrow and top heavy, which makes it the household object most eager to tip. Washington’s plumbing code goes further than the national model here. Instead of requiring restraint only in certain seismic zones, the state applies it to every water heater, with straps in the upper and lower thirds of the tank and the lower strap kept a few inches clear of the controls.
How the strap is made counts just as much as whether it exists. Several local building departments specifically reject perforated plumber’s tape, the thin punched metal that used to be standard. Tanks tore right through it in the California quakes of 1989 and 1994. Heavy gauge steel strapping wrapped about one and a half times around the tank and lagged into wall studs is what holds. Many older installs fall short in ways that are easy to spot once you know what to look for.
- Thin perforated tape that bends like foil when you press it
- A single strap, or two straps bunched near the middle of the tank
- Screws driven into drywall instead of studs or a solid backing block
- A gap of several inches between the tank and the wall, giving it room to build momentum
- Rigid copper or steel pipe running straight into the top of the heater
That last point is easy to miss. Even a well strapped tank shifts a little, and a rigid connection turns that small movement into a cracked fitting. Flexible connectors on the water and gas lines let the tank sway without breaking anything. Since replacing a water heater in Washington requires a permit, a swap is also the natural moment to get strapping, connectors and the expansion tank brought up to current rules all at once.
Stiff Pipes Break Where Flexible Ones Bend
Tacoma has a lot of early 1900s housing in the North End, the Stadium District and Hilltop, and much of it still runs galvanized steel supply lines. Galvanized pipe corrodes from the inside, and the threaded joints are the thinnest point on the line. Decades of rust leave those threads brittle, so a sudden jolt tends to snap a pipe at the fitting rather than along a straight run.
Drains carry their own risk. Cast iron stacks get brittle at the hubs as they age. Clay side sewers are laid in short sections, and root intrusion often has already loosened the joints before any shaking starts. In most Tacoma cases the property owner is responsible for the side sewer between the house and the city main. A break out there is a private repair, not a city one.
Copper holds up better, though long rigid runs pinned tight at both ends can still shear. PEX, the flexible plastic line now common in repipes, simply bends with the building. If you’re already planning to replace aging galvanized pipe, the earthquake question becomes one more reason to do it. Ask for some slack and proper sleeves wherever lines pass through the foundation, since that’s where the house and the ground move separately.
Where a Shake Becomes a Fire
The Washington Department of Natural Resources names broken gas lines as the leading cause of fires after earthquakes. That puts the gas side of your plumbing ahead of the water side in sheer danger, even though water damage is far more common.
Automatic seismic shutoff valves sit just past the meter and close when they sense strong motion. They’re a sensible upgrade for homes with gas water heaters, furnaces or ranges, but the trade-off is real. A strong jolt or a passing heavy truck can trip some models, and once gas is off, getting it back means relighting every pilot. Installation needs a permit and a licensed installer.
Without one, keep a wrench tied near the meter. A quarter turn so the valve sits crosswise to the pipe shuts off the supply. Only do this if you smell gas or hear a hiss, because once it’s closed, Puget Sound Energy has to come out to restore service and relight appliances, and after a big quake that wait could stretch for days.
Fifty Gallons of Drinking Water You Already Own
A standing water heater is one of the best emergency water supplies in the house, which is another reason the strap matters. City mains often break during strong quakes, and a broken line can drain your home of usable water right when you need it. Getting to the water in your tank safely takes a few deliberate steps.
- Close the main shutoff valve first so contaminated water from damaged city lines can’t flow into the tank.
- Turn off the power at the breaker, or set a gas heater to off.
- Give the water time to cool.
- Open a hot water faucet somewhere upstairs so air can enter the tank.
- Attach a clean hose to the drain valve at the bottom and fill clean containers, letting the first bit of sediment run off.
All of this depends on knowing where your main shutoff actually is. In older Tacoma homes it’s usually on a basement or crawl space wall where the supply line enters. Many of those old gate valves seize after years of sitting untouched, so turning it once a year is a small habit that pays off. The curb valve in the meter box works too but generally needs a meter key.
The Hour After the Shaking Stops
Once things settle, your ears are the first tool. Running water inside walls, a hiss near the gas meter or a steady drip under a sink all point somewhere specific. With every fixture off, check the leak indicator on your water meter. If it’s spinning, water is escaping somewhere you can’t see.
Hold off on flushing toilets until you’re confident the drains and side sewer are intact. A cracked line under the house can send waste straight into a crawl space, and aftershocks, which can continue for days or weeks, may widen a crack that started small. A flashlight sweep of the crawl space before anything gets used is time well spent.
The work itself doesn’t have to happen all at once. A proper strap and flexible connectors on the water heater cost little and close the biggest gap. Learning the shutoff valves takes an afternoon. Repiping old galvanized lines or replacing a tired clay sewer can follow on a sensible timeline, guided by the age of the house and the ground it sits on. Each step makes the next shake a little less expensive.
