Why Is My Water Heater Not Working? 5 Possible Reasons

A water heater that has stopped producing hot water is rarely a mystery once you know where to look. Most failures come down to one of a handful of causes, and a few of them you can check safely yourself before calling anyone. Below are the five we see most often in Fraser Valley homes, what each one looks like, and where the line sits between a homeowner check and work that needs a licensed gas fitter.

1. The pilot light or igniter has failed (gas tanks)

On a gas water heater, no hot water at all — with no burner sound and no warmth from the tank — usually points at ignition. Older units use a standing pilot light; newer ones use an electronic igniter. Either can fail, and so can the thermocouple, the safety device that senses the flame and shuts off gas when it does not detect one.

A pilot that lights but will not stay lit almost always means a failing thermocouple. That is a real repair, not a relight. If you smell gas at any point, stop, leave the house, and call your gas utility from outside — do not keep trying.

2. A tripped breaker or high-limit switch (electric tanks)

Electric tanks have two things that cut power: the breaker in your panel, and a red reset button on the upper thermostat behind the access panel, called the high-limit or ECO switch. Check the breaker first. If it has tripped, reset it once.

If it trips again immediately, stop there. A breaker that will not hold usually means a shorted element or damaged wiring, and repeatedly resetting it is how a fault becomes a fire. The same applies to the reset button: it exists because the water got too hot, so a switch that keeps tripping is reporting a genuine problem, not a nuisance.

3. A burned-out heating element or failed thermostat

Electric tanks have two elements, upper and lower. When the lower one fails you typically get a small amount of hot water that runs out fast. When the upper one fails you often get none at all. A failed thermostat produces similar symptoms, which is why the two are diagnosed together rather than guessed at.

Water that is lukewarm no matter what the dial says, or that runs hot then cold within a single shower, points here. Elements are a routine replacement; the diagnosis is what matters, because swapping the wrong one fixes nothing.

4. Sediment has built up in the tank

Minerals settle out of the water and collect at the bottom of the tank. On a gas unit that sediment sits between the burner and the water, so the burner works harder and longer to heat less. You will often hear it before you notice it: rumbling, popping, or a kettle-like sound as steam bubbles force their way up through the layer.

Sediment is the most preventable cause on this list. Draining and flushing the tank as part of routine maintenance keeps it from accumulating, which protects both efficiency and the life of the tank.

5. The tank has simply reached the end of its life

Most conventional tanks last somewhere in the region of eight to twelve years. The sacrificial anode rod inside is designed to corrode so the tank lining does not, and once it is spent, the tank itself begins to go.

Rusty or discoloured hot water, damp patches around the base, or any visible weeping from the tank body means the tank is failing rather than misbehaving. A leaking tank is not repairable — the shell has corroded through — and it will not improve on its own. If you find water pooling underneath, shut off the water supply to the tank and get it looked at promptly, because tank failures tend to end suddenly rather than gradually.

What you can check yourself, and what you should not

Safe to do: look at the breaker, confirm the thermostat setting has not been knocked down, press the reset button once, and check whether the gas shut-off valve is open. Anything that resolves at that level is worth five minutes of your time.

Not safe to do: relight a pilot when you can smell gas, reset a breaker that keeps tripping, replace a thermocouple, gas valve, or heating element, or open a tank that is leaking. In British Columbia, gas work requires a licensed gas fitter — that is a legal requirement, not a preference.

Frequently asked questions

Why does my hot water run out so much faster than it used to?

Usually sediment or a failed lower element. Both reduce how much of the tank's volume is actually being heated, so the usable hot water shrinks even though the tank size has not changed.

Is it worth repairing a water heater, or should I replace it?

Age is the deciding factor. On a tank under roughly eight years old, a repair is generally the sensible call. Past ten to twelve years, spending on a repair often means paying twice within a short window. A leaking tank is always a replacement.

Why is my water rusty or discoloured?

Most often a spent anode rod, which means corrosion has moved on to the tank itself. If the discolouration appears only on the hot side, the tank is the source. If it is on both hot and cold, the issue is upstream of the water heater.

Can a water heater be dangerous when it fails?

It can. The two risks worth taking seriously are a gas leak and a failed temperature-and-pressure relief valve. Never cap, plug, or bypass a T&P valve — it is the device that prevents a tank from becoming a pressure vessel.

How often should a water heater be serviced?

Once a year for a conventional tank — flushing sediment and checking the anode rod, the T&P valve, and the burner or elements. That schedule is what keeps causes one, three, and four on this list from arriving in the first place.

Getting it sorted

If the simple checks above have not restored hot water, the next step is a diagnosis rather than a parts swap. Big Valley Heating & Sheet Metal has been working on Fraser Valley homes since 1986, and our licensed technicians handle both conventional tanks and tankless systems.

You can read more about our water heater repair and replacement services, see what is currently available on our promotions page, or get in touch to book a visit. We are in the office Monday to Friday, and you can reach us on (604) 467-6474.