Preparing for an Earthquake
Fresh water after a disaster may be as close as your hot water heater provided however, that it remains standing upright. A typical water heater holds 30-40 gallons of water. This supply of water is extremely vulnerable to the ground swells and rolls of earthquakes as well as the ground shaking, causing them to easily tip over.
You can protect this valuable resource by securing your water heater to the wall studs.
How to Strap Your Water Heater
Because many tanks burst through their strapping in both the 1989 Loma Prieta (San Francisco) and the 1994 Northridge (Los Angeles) earthquakes, experts have modified the recommended procedure for strapping water heaters.
Section 510.5 of the Uniform Plumbing Code states, “In seismic zones 3 and 4, water heaters shall be anchored or strapped to resist horizontal displacement due to earthquake motion. Strapping shall be at points within the upper one-third (1/3) and lower one-third (1/3) of its vertical dimensions. At the lower point, a minimum distance of four (4) inches shall be maintained above the controls with the strapping.”
The Uniform Plumbing Code does not require a certain size or type of strapping, however experts agree that a strapping system specifically designed for water heaters is best. These types of strapping systems are usually designed with metal straps that fit securely around the water heater and bolt to the wall framing. Plumber’s tape is not recommended. Many water heaters in both the 1989 and 1994 earthquakes burst through the plumber’s tape that was intended to keep them secure. Plumber’s tape is now felt to be too brittle to be effective.
There should be very little space between the water heater tank and the wall. If there is more than 1 to 2 inches, attach a wooden block (a length of 2x4 or 1x4 lumber) that spans the distance between the wall studs behind your water heater with long lag screws. This will prevent the water heater from tipping backwards.
Follow the manufacturers instructions if you have purchased a water heater strapping kit. Otherwise, wrap nylon strapping 1 ½ times around the tank. Start by placing the strapping at the back of the tank. Bring it to the front and then take it back to the wall. Secure this strapping to the wall studs or the wood block using several ¼ inch x 3 inch or longer lag screws with oversized washers. If you are securing it directly into concrete, use ¼ inch expansion bolts in place of the screws.
Replace all copper and metal piping with flexible natural gas and water line connectors.
Water Heaters in Garages
Water heaters generating a glow, spark, or flame capable of igniting flammable vapors may be installed in a garage, provided the pilots, burners, or heating elements and switches are at least eighteen (18) inches above the floor level.
All water heaters installed in areas where they may be subjected to mechanical damage shall be suitably guarded against such damage by being installed behind adequate barriers or by being elevated or located out of the normal path of a vehicle using any such garage.