Plumbing
No Hot Water? Water Heater Troubleshooting Guide
· by Diamond Home Services
Why your water heater stopped producing hot water, which checks are safe to do yourself, repair costs in the GTA, and when to replace instead.
No hot water at all, or hot water that runs out in five minutes — two different problems with different fixes. Here is how to tell them apart.
No hot water at all
Gas tank: the pilot is out or the thermocouple failed. Modern units use a sealed pilot assembly with a status light — count the flashes and check the label. If it will not relight and hold, the thermocouple or gas control valve is done.
Electric tank: almost always a tripped high-limit reset (the red button behind the upper access panel) or a failed heating element. A tripped limit that trips again means a failed thermostat or element, not a fluke.
Hot water runs out fast
Sediment. Toronto water leaves mineral deposits that insulate the burner from the tank, and in bad cases occupy a third of the volume. A dip tube failure produces the same symptom. Annual flushing prevents most of it.
Lukewarm water only
Crossed connection at a mixing valve or single-lever faucet, a failed lower element on an electric tank, or a mixing valve set too low.
Rumbling, popping or banging
Sediment boiling under the burner. Not immediately dangerous, but a clear warning that the tank is scaling and its remaining life is shortening.
Water around the base
If the tank itself is leaking, it is finished — tanks fail from the inside out and cannot be patched. Shut off the water and gas or breaker and call immediately, before you are drying out a finished basement.
Repair or replace
Tanks last 8–12 years in the GTA. Past year 10, put repair money toward a replacement. If your tank is rented, check the contract before paying anyone for parts — service may be included.
Typical costs
Thermocouple $220–$350. Element and thermostat $250–$420. Full flush and inspect $150–$220. Replacement is quoted after we see the venting and connections.
Get it sorted today
See water heater repair pricing and the service page, then call us or request a free quote.