Water heater making popping or rumbling noise
moderate 45–90 min
Tools: garden hose, bucket, flat screwdriver · Materials: descaling solution (optional)
Steps
- The popping is water boiling under a layer of sediment; it is a maintenance signal, not an emergency.
- Switch electric power off at the breaker, or turn a gas heater to pilot, and close the cold inlet valve.
- Connect a hose to the drain valve, run it to a floor drain or outside, and open a hot tap upstairs to let air in.
- Open the drain valve and let the tank empty; when it slows, briefly open the cold inlet to stir the sediment and keep draining until the water runs clear.
- Close the drain, refill with the hot tap open until it runs steadily, then restore power or gas.
- Repeat once a year — twice in hard-water areas.
Stop and call a pro if
- the drain valve is clogged with sediment and will not flow, or will not close afterwards
- the popping continues after a full flush — the element or the tank bottom is scaled solid
- you find rust flakes in the drained water on a tank older than 10 years
What a pro does that you can't
A plumber flushes a tank whose drain valve has seized, replaces the valve, descales or replaces scaled elements, and recommends a water softener when the scale comes back within months.
DIY cost: $0–15 for a hose