Water Supply Noise due to Thermal Expansion?
We had similar issue with hot water heater. Went through three of them in 15 years. Plumber confirmed issue was related to thermal expansion. Consider getting a thermal expansion tank on the supply side of the water heater.  If your water company installed a check valve on their side of the supply to the house, to eliminate backflow in to the city water suppy, your thermal expansion is stressing the holding tank in your water heater.  That can compromise the tank integrity, causing leaks and flooding from a ruptured tank.