Any malfunction involving natural gas needs a professional gas fitter. And as with any appliance, regular maintenance is the best way to avoid problems.
Common hot water tank problems
- No hot water
- Not enough hot water
- Rust-coloured water
- Rotten-egg odour
- Low rumbling or popping noise
- High-pitched whining
- Water leaking around the base
Common tankless water heater problems
- No hot water
- Water not hot enough
- Water too hot
- Burner won't ignite
- Burner too noisy
- Low water pressure
- Temperature fluctuates (“cold water sandwich”)
What these symptoms usually mean
No hot water
On a gas tank, often a pilot that's gone out, a worn thermocouple or a failed gas control valve. On a tankless unit, it can be an ignition fault, a gas supply problem or a unit that's locked itself out.
Rumbling and popping
Sediment has settled on the bottom of the tank. Water trapped under it boils and pops. It wastes energy and, over time, shortens the life of the tank.
Rusty water, or a rotten-egg smell from the hot taps
Often a sign that the anode rod, which protects the tank from corrosion, is worn out or reacting with bacteria in the water. Replacing it early can add years to a tank. A rotten-egg smell in the air near the heater is different: treat it as a gas leak.
Water around the base
Could be a loose fitting, the drain valve, or the temperature and pressure relief valve doing its job. If the tank itself is leaking, it needs to be replaced.
Tankless temperature swings
A brief burst of cold between hot (the “cold water sandwich”) is normal when a tap is turned off and on again quickly. Water that's never quite hot enough often points to scale buildup in the heat exchanger, a clogged inlet filter, or a unit that's undersized for demand.
Maintenance that prevents most repairs
- Flush the tank to clear sediment from the bottom
- Test the temperature and pressure relief valve
- Inspect and replace the anode rod when it's worn
- Check the burner, pilot and venting on gas units
- Descale tankless heat exchangers and clean the inlet filter
- Check gas connections for leaks and confirm the temperature setting
A yearly check, following your manufacturer's recommendations, keeps your water heater running efficiently and catches small problems early. It also protects your warranty, since many tankless warranties require regular maintenance. Not sure which kind you have? Our water heater guide explains the differences.
