As an Amazon Associate, we earn from qualifying purchases at no additional cost to you.
The IRC specifies that electric water heaters in Seismic Design Categories D (and C for townhouses) must be double strapped. Some local codes also say that heaters in categories E and F need to be strapped. Even if your local code does not say it, if you live in an E or F area, you should strap your heater.
For people who live in areas prone to natural disasters, strapping water heaters is a standard regulation. This necessary safety measure is actually a pretty simple process once you know a little about it.
Whether you are looking to do it yourself, want to know if you are up to code, or just want to know what the plumber you hired is doing, this is an easy guide to the basics of earthquake strapping.
Strapping Requirements Depend on Location
The IRC mentions seismic bracing for a water heater in Section P2801.8. The regulations are different for the different seismic design categories.
Seismic design categories (SDCs) refer to the classifications given to a building depending on the severity of ground movement expected in that location in the event of an earthquake.
The categories range from A (minor ground movement) to F (severe movement in an area located on a fault line). Thus, strapping requirements for your water heater are going to depend on where you live and what seismic activity is prevalent in that area.
The IRC requires water heaters to be strapped in areas classified as SDC D (D0), D1, and D2. According to the IRC scope found in Section R101.2, this applies to any:
“detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress and their accessory structures not more than three stories above the grade plane in height”.
This D classification denotes that very strong ground movement is anticipated, and this increases in severity with the number assigned to the category, with D2 experiencing more severe shaking than D0.
Furthermore, Section P2801.8 specifies that electric water heaters in townhouses in SDC C areas (areas of strong shaking) must also be strapped.
In order to correctly anchor a heater for significant ground movement, there must be two strapping points, on the top and the bottom third of the appliance, or according to manufacturer recommendations. These must be able to resist up to one-third of the heater’s weight.
Regardless of where in the house the electric water heater is located (for example, in the crawl space, basement, designated closet, or garage), strapping rules apply.
States Requiring Double Strapped Water Heaters
Two straps are needed in any state that falls SDCs C to D as per the IRC, as well as those for which local codes require water heater strapping (I will speak more on local codes in the section below).
Furthermore, while the IRC does not explicitly mention SDCs E and F, I cannot imagine that strapping your electric water heater (along with some other items!) would not be required in areas of such extreme seismic activity.
States that fall within moderately high to very high risk of seismic activity are:
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- South Carolina
States with Additional/Adapted Code Requirements
Certain states have amended and additional local codes beyond IRC requirements due to seismic climates. It is recommended that you check local codes to ensure that your water heater complies with state regulations.
Some examples of states with differential code requirements are Alaska, Nevada, and California.
According to amendments mentioned in Section 507.2 of the Uniform Plumbing Code of Alaska and Section 507.2 of the Uniform Plumbing Code of Nevada, all water heaters must be strapped in areas classified as SDCs C to F.
In California, legislation states that all water heaters must be anchored (at minimum) according to Section 507.2 of the Uniform Plumbing Code of California.
How to Strap an Electric Water Heater
In order to secure your water heater, you will need to install two heavy-gauge metal straps. The lower strap must maintain a distance of 4” from the controls, while the upper strap should sit 9” below the top of the heater.
You can purchase a strapping kit, which will contain heavy-gauge straps, lag screws, washers, tension bolts, and spacers. Or you can purchase the separate materials yourself.
There should be less than 2” between the heater and the wall to prevent it from tipping backward. Attaching a wooden block to the wall can remedy any extra space.
The straps can be secured to wall studs, wooden blocks, or directly into a concrete wall. For the last option, you are going to need 1/4″ expansion bolts.
Otherwise, you can use 1/4″ x 3” (or longer) lag screws to secure the straps to the wooden blocks or wall stud. The lag screw should at minimum have a 1” thread penetration.
For reinforcement purposes, an oversized and flat washer must be placed in-between the screws and straps to prevent tearing.
Strapping an Electric Water Heater: Cost
What you will need:
- Metal strapping (amazon link).
- 1/4″ x 3” lag screws (amazon link) or longer. Or 1/4″ expansion bolts (amazon link).
- Washers (amazon link).
- A strapping kit (amazon link).
There are no labor costs if you install the bracing yourself. It might only cost $18-$100 depending on what materials and tools you need to purchase.
Within the price ballpark of $700-$1,500, you can hire a licensed plumber. While more costly, this would ensure that your installation and strapping are up to code. It also might be cheaper if you are just bringing strapping up to standard.
Risks of Not Strapping as per Code
If your heater is not strapped there are risks for fires, electric shocks, broken water lines, and flooding in the event of an earthquake.
Not only will this result in expensive damage to the heater, but this can result in expensive damage to your residence.
An unstrapped heater unit itself can also pose a health risk to your family and pets as it might fall over and hurt someone if there is an earthquake.
Adhering to the strapping codes for your area can be more valuable than you might think for a crisis.
In the event of natural disasters, it is crucial to ensure that you have access to clean drinking water. In this case, your code-compliant (and therefore intact) electric water heater could provide an essential resource for you and your family.
It is, however, important to double-check that your water in the heater has not been contaminated.
It goes without saying, but I’ll say it anyway, while tankless water heaters have many benefits, they are not going to be any good in this regard.
I would also like to mention that it is in your best interests to maintain a clean water tank as bacteria can thrive in a wet and hot environment. Regular maintenance helps to ensure that your water heater can be a resource in times of disaster.
Please note that you will need to turn off the power and water supply to the unit before you can safely access the water!
Should You Strap a Heater if You Don’t Get Earthquakes?
The official and practical purpose of strapping your water heater is for seismic bracing. It is intended to prevent movement during earthquakes.
According to international regulation, there is no other reason to strap your water heater unless you are in an area that commonly anticipates seismic activity and falls within the applicable SDCs.
Related article: Is It OK To Store Things Near a Water Heater
Amazon and the Amazon logo are trademarks of Amazon.com, Inc, or its affiliates.