No hot water, insufficient supply, discoloured water, leaks and strange noises — what causes them and what to do.
A complete loss of hot water is the most urgent problem. The cause depends on your system type:
Electric systems: Check your circuit breaker first — a tripped breaker is the simplest fix. If power is reaching the unit, the heating element or thermostat may have failed. Elements can be tested and replaced by a licensed plumber.
Gas systems: Check whether the pilot light is lit. If it has gone out, relight it following the manufacturer's instructions. If it will not stay lit, the thermocouple likely needs replacement. If you smell gas, turn off the supply immediately and call a licensed gas fitter.
Regular maintenance catches deteriorating elements and thermocouples before they fail completely, avoiding the cold-shower emergency.
The system produces some hot water but not enough to meet household demand. Common causes:
A licensed plumber can diagnose whether the issue is capacity, maintenance or component failure — and recommend the most cost-effective solution.
Rusty, brown or metallic-tasting hot water indicates internal corrosion. The most likely cause is a depleted sacrificial anode — once consumed, the tank walls begin to rust. Replacing the anode may resolve the issue if caught early. If the tank is already significantly corroded, replacement is the only safe option.
Foul-smelling water (often described as a rotten egg odour) is typically caused by bacteria reacting with the anode rod, particularly in systems with low usage or well water. Flushing the tank and treating with hydrogen peroxide usually resolves it. Persistent odour may require anode replacement with an alternative material.
Leaks range from minor drips to serious flooding. Identify the source:
Never ignore a leak. Even a small drip can cause significant damage to flooring, walls and cabinetry over time — and a tank leak can release hundreds of litres if it fails catastrophically.
Popping, banging, rumbling or gurgling sounds from your hot water system almost always indicate sediment buildup. As sediment hardens on the tank floor, trapped water beneath it overheats and creates steam bubbles — producing those unsettling noises.
The fix is straightforward: drain and flush the tank to remove accumulated sediment. If the buildup is severe and has been present for years, the sediment may have hardened to the point where flushing alone cannot remove it — in which case the system may need professional descaling or, if the tank is old, replacement.
Prevention is simple: schedule an annual tank flush. This takes 20–30 minutes and prevents sediment from accumulating to problematic levels.
Common causes are sediment buildup reducing tank capacity, a failing heating element, thermostat set too low, or a system that is undersized for your household's current demand.
Not immediately dangerous, but it indicates sediment buildup that is reducing efficiency and accelerating wear. If left untreated, it can lead to overheating and premature tank failure.
Bacteria reacting with the sacrificial anode rod, particularly in low-use systems or those connected to well water. Flushing and treating the tank usually resolves it.
Yes. Turn off the power (or gas) and the cold water inlet valve to prevent further water damage. Then call a licensed plumber for assessment.
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