HeyBub wrote:
....
And we are sorry for your recent loss.

Indeed...

Wild guess: You have a defective thermostat on the water heater (or it's set
way too high) causing the water to boil. It is extremely unlikely that the
pressure would build sufficiently to rupture the tank, ...

That's what the safety relief is for, and if it were boiling any
significant amount it would lift.

But, it could still be either maladjusted or malfunctioning and hotter
water will cause more air out of solution plus perhaps more nucleate
(localized) boiling on the heater (assuming electric) element(s)...

So agree first question is "is it hotter than normal?"

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