Electric water heaters may hiss while an element is heating, but a buzzing or popping sound indicates a problem. The buzzing noise may mean there’s scaling on a heating element or that an element is not properly matched to manufacturer specifications for the model. In either case, your water heater is probably wasting energy. Elements for water heaters are user accessible for servicing.
Find the make and model number of your water heater. The manufacturer's logo will be displayed on the upper front of the unit. The model number will be listed on the nameplate with the circled UL mark. Write down the brand name and the model number.