Hot water tanks are always going to give you issues and problems that could become very serious. One problem that gets asked a lot and there are usually never any good answers is what do you do if your water heater is making a hissing noise.
First things to do is check the pressure valve. You want to make sure that the pressure in the take isn’t getting too high because that might mean you have to replace some heating element. Next you want to let it run for a while and see what happens. Most likely it’s some sludge that is on the bottom element. You might have to replace that and calling your Phoenix plumber will be a really smart decision.