Rumbling, popping or banging from water heater

Common Causes

1. Calcium carbonate sediment from hard water accumulating on the tank floor
2. Water being superheated through the sediment layer, producing steam pockets that "pop"
3. Advanced corrosion inside the tank

What You Can Try First

1. Attach a garden hose to the drain valve at the bottom of the tank
2. Turn off the cold water supply to the tank
3. Set the thermostat to "vacation" or "pilot" to allow water to cool slightly
4. Open the drain valve and flush 10-15 gallons of water into a bucket or drain — observe for sediment (gritty, rust-coloured particles)
5. Close the valve, restore supply, and relight pilot or restore thermostat
6. Repeat annually in hard water areas like Innisfail

When to Call a Pro

• Tank is more than 10 years old and flushing has not resolved the noise
• Water heater is taking much longer than usual to recover after use
• You notice rust-coloured water from the hot water taps
• Pressure relief valve has discharged — have it inspected

Alberta Context

Innisfail's hard water (140-200 mg/L) causes sediment to accumulate 2-3x faster than in soft-water regions. Annual flushing is strongly recommended. A tank that has never been flushed and is 8+ years old may have sediment build-up that cannot be fully cleared — at that point, replacement is more economical than continued maintenance.