Symptoms
- Rumbling, popping, or crackling sound during the heating cycle
- Noise has developed gradually over months or years
- Tank hasn't been flushed in a long time or ever
- Hot water may take longer to arrive or run out faster
Likely causes
- CommonSediment buildup at the bottom of the tankMineral sediment traps pockets of water that heat, expand, and pop against the tank bottom and sediment layer.
- CommonHard water accelerating sediment accumulationAreas with hard water see faster mineral buildup inside the tank.
- CommonTank never flushed since installationSediment accumulates steadily without periodic flushing.
What to do
- Turn off power (electric) or set the gas control to pilot, and let the water cool if it's been recently used.
- Connect a garden hose to the drain valve at the bottom of the tank and run it to a floor drain or outside.
- Turn off the cold water supply valve to the tank before opening the drain valve, or flush with supply on per your model's guidance.
- Open the drain valve and let water flow until it runs clear, opening a hot water tap upstairs to help it drain.
- Close the drain valve, remove the hose, restore the cold water supply, and let the tank refill fully before restoring power or gas.
- Plan to flush the tank annually going forward to slow sediment buildup and reduce noise.
Tools and parts
- Garden hose
- Bucket (if no floor drain)
When to call a pro
If flushing doesn't quiet the noise, or heavy sediment has built up over many years, a plumber can assess whether the tank's efficiency and lifespan have been significantly affected.
Safety
Use caution
Let the water cool before draining to avoid scalding, and be careful handling the hot water and hose during the flush.