It usually comes down to sediment, not extreme hardness. The City of Redding pulls about 77% of its supply from surface sources like the Sacramento River and Whiskeytown and the remaining 23% from groundwater, and classifies its treated water as soft — though the groundwater portion tests moderately hard, and rural homes on private wells often run harder still. Whatever the source, minerals and grit settle in the tank, and that buildup is what wears a water heater out early.
Sediment settles to the bottom of the tank, insulates the burner or heating element, and forces the unit to run hotter and longer to heat the water above it. Eventually the metal fatigues, the tank cracks, and it floods the garage.
We've seen this pattern thousands of times across Redding, Shasta Lake, Anderson, Palo Cedro, and Bella Vista. If your unit is rumbling, popping, producing rusty water, or past 8 years old, plan the replacement before it fails on you — it's cheaper than the flood damage cleanup.