Product review (5 stars): Solid as a Rock
The Watts E-25 wrap-around earthquake straps were more than sufficient for my 40 gallon tank. The directions for installation were excellent.  And the installation was a breeze.  Once I had tightened the straps, my 40 gallon tank was immovable.

I do not live in an earthquake zone but wanted the 40 gallons of water in my hot water heater to be secure in case a hurricane hit our coastal town.  If a storm surge or extremely heavy rains were to cause flooding, 40 gallons of potable water could make a critical difference.