Hi House.
If some of your 120 volt outlets aren't working, and the 120 volt side of your water heater is inop, I'd be looking for a tripped circuit breaker(s) - not fuses. Fuses are usually for 12 volt systems and circuit breakers are for 120 volt systems. When you find your breaker panel, flip the circuit breakers off manually and then flip them back on again. Oftentimes circuit breakers can trip and be off, even though they look like they're on. Does the GFI outlet you mentioned work? GFIs are notorious for failing and if other outlets are downstream from a bad one, they won't work either.
Kev