What it usually means, the likely causes in order, what to safely try first, what a pro charges in Canada, and when to stop and call one.
This guide covers the common cases. Describe your exact problem and get a personalized diagnosis — free to start, with a DIY vs. call-a-pro verdict and a real cost estimate.
No hot water — or a shower that turns cold in three minutes — is a water heater story in almost every case. The heater has stopped heating (a failed element, igniter, or a tripped safety), or it heats but can't keep up because sediment is insulating the heat source, the tank is undersized for new demand, or the unit is simply at the age where replacement beats repair. Before you assume the worst, there are two free checks — breaker and pilot — that account for a real share of 'dead' heaters, and the tank's age label tells you how much money any repair is worth spending.
No hot water is a comfort emergency rather than a safety one — most households can manage a day or two, which means you can usually book a normal appointment instead of paying emergency rates. Exceptions: a leaking tank (water around the base means the tank itself may be failing and can worsen suddenly — shut off its water supply and book promptly), any smell of gas near a gas unit (leave, and call your gas utility), or a popping/rumbling tank that's overdue for attention.
Electric tanks have a dedicated breaker and a high-limit reset button on the unit itself. Either can trip and leave you with a full tank of cold water that looks like a dead heater. It's the first check because it's free and common after power events.
Electric tanks usually have two elements; when one fails you often get some hot water that runs out fast rather than none at all. On gas units, the igniter or pilot assembly is the usual failure — the burner simply never fires.
A pilot can be blown out by a draft or fail because its thermocouple — the safety sensor that proves the flame exists — has worn out. The heater then refuses to run at all, by design. Relighting instructions are printed on the tank; a pilot that won't stay lit is a parts problem, not a technique problem.
Minerals settle at the bottom of the tank over years and insulate the water from the heat source, so the heater works harder, rumbles or pops as it heats, and delivers less hot water — the classic 'runs out quickly' complaint in a unit that still technically works.
A thermostat bumped down, or one that's failed, can leave water lukewarm. If one shower runs properly hot and the tank setting hasn't changed, the issue may be a single fixture's mixing valve rather than the heater — worth checking before the heater is condemned.
| Job size | Typical estimate (CAD) |
|---|---|
| Simple fix — the straightforward version of this repair | $120–$250 |
| Major job — complex, hidden, or replacement-level work | $400–$1,200 |
Estimates only, calibrated to Greater Toronto Area trade rates and adjusted by region on this site — not a quote. Your exact price depends on the cause, parts, and access. A personalized diagnosis narrows this range using your specific symptom.
Breaker and pilot checks are homeowner-safe and worth doing before any call. Beyond that, heater work crosses into gas lines, high-voltage elements, and pressure relief valves — licensed territory in most places, and work your insurer will ask questions about if it's DIY. A pro also brings the repair-vs-replace judgment: ask anyone quoting a repair on an older tank what the same money does toward a replacement, and get the tank's age into the conversation.
Not necessarily dying — often it's sediment insulating the bottom of the tank, or one of two elements failed on an electric unit, so only part of the tank is actually hot. Both are repairable, but on a unit that's also old, weigh the repair against replacement; a tank that's lost capacity to sediment has usually been losing efficiency for a while too.
No. A breaker that trips repeatedly is protecting you from a fault — commonly a shorted heating element. Reset once after checking the obvious; if it trips again, leave it off and call a pro. Repeatedly forcing a circuit that protects a water-filled electric appliance is how a repair turns into a hazard.
Tank-style heaters commonly serve somewhere around a decade, give or take, depending on water quality and maintenance — hard water and no flushing shorten that. The rating sticker's manufacture date is your ground truth: a heater well past the ten-year mark that needs a major part is usually money better put toward a new unit with a fresh warranty.
When every fixture changes together, the thermostat is the prime suspect — bumped, failing, or set incorrectly after other work. Check the dial setting first (the tank label shows its current setting and the manufacturer's guidance). Scalding water is also a safety issue for kids and older adults, so don't just live with it in either direction.
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