Final answer:
In seismic design categories high and higher, water heaters shall be anchored or strapped to resist horizontal displacement due to earthquake motion.
Step-by-step explanation:
In seismic design categories high and higher, water heaters shall be anchored or strapped to resist horizontal displacement due to earthquake motion.
This requirement is based on the fact that earthquakes produce strong horizontal shaking, which can cause unanchored water heaters to topple over or move during an earthquake.
Anchoring or strapping the water heaters helps prevent damage to the water heater as well as potential water leaks or gas leaks that could result from their displacement during an earthquake.