There are many reasons why a hot water heater makes noise. Several of those reasons involve minor repairs or maintenance and don’t require a whole water heater replacement. Homeowners should be aware of how water moves and changes inside a water heater and in different parts of a home to understand what causes a water heater to make noise. Understand the cause of water heater noises – including popping, crackling, humming, hammering or knocking, screeching, ticking or tapping, sizzling, and more – and how you can resolve the sounds with simple maintenance or if you need a professional.