Water heater rumbling, popping or screeching? Each noise points to a different problem.
Water heaters are supposed to be boring. When one starts making noise it is telling you something specific, and the sound is a surprisingly reliable diagnostic.
Cause: sediment. This is the most common noise in Arizona by a wide margin, and it is a direct consequence of how hard the water is here.
Minerals settle out of the water and form a hard layer on the bottom of the tank. Water gets trapped underneath it, the burner heats that water past boiling, and steam bubbles force their way up through the sediment. That is the popping you hear.
Why it matters: the burner is now heating through an insulating layer of rock. The tank runs hotter, uses more gas, recovers more slowly, and the steel at the bottom is under thermal stress it was not designed for. Sediment is the leading reason water heaters in Arizona fail years earlier than their rating.
What to do: a full flush. If the tank is young and has never been flushed, this often buys back years. If it is a decade old and heavily scaled, flushing sometimes dislodges enough material to expose an existing weak spot - we will tell you honestly which situation yours is before touching it. Either way it falls under water heater repair & replacement.
Cause: restricted flow. Water forcing through a partly closed valve. Check the shut-off above the heater is fully open, then the T&P valve. A whistle from the T&P specifically is worth attention because that valve is a safety device and it should never be partly seated.
Usually harmless. Pipes expanding and contracting against framing as hot water moves through them. Heat traps in the nipples on top of the tank also tick. If it started at the same time as another symptom, mention it, otherwise it is normally nothing.
Cause: water hammer, not the heater. Fast-closing valves - washing machines and dishwashers are the usual culprits - stop moving water abruptly and the shock travels through the pipes. Fitting arrestors solves it. Ignoring it puts repeated shock load on every joint in the house.
On an electric heater, usually the upper element vibrating. Not urgent, but worth tightening.
Treat this as urgent. Sizzling generally means water is dripping onto the burner assembly, which means the tank or a connection is leaking. An actual boiling sound can mean the temperature control has failed. Turn the unit off - gas valve to off, or the breaker for an electric unit - shut the cold supply above the heater, and call emergency plumbing.
The maintenance that actually extends tank life in Arizona: flush the tank annually, and have the anode rod checked every two to three years. The anode is a sacrificial metal rod that corrodes so the tank does not. Once it is gone, the tank starts. Replacing a rod costs a fraction of replacing a heater, and almost nobody does it.
Repair usually wins if the unit is under about eight years old. Past twelve, on Arizona water, you are often spending money to postpone the inevitable by a few months. And if the tank itself is weeping, no repair holds - that is a water heater repair & replacement replacement, and many people use the moment to look at tankless water heater installation instead, particularly if they have been running out of hot water anyway.
Scale. If you are on unsoftened Arizona water, sediment will keep coming back no matter how many times we flush the tank. A water softener & water treatment installation is the thing that actually changes the outcome - it protects the heater, the fixtures, the dishwasher and the washing machine at the same time.
Call and describe what you are seeing. We will tell you whether it is a tonight problem or a Tuesday problem.