Water Heater Fails: Why It Happens and How to Fix It

If you suddenly have cold showers, you’re probably wondering what went wrong with your water heater. Most failures are caused by a few easy‑to‑spot problems. Knowing the symptoms can save you time, money, and a cold morning.

Top Reasons Your Heater Stops Working

No power or pilot light. Electric heaters need a functioning breaker, while gas units rely on a lit pilot. If the breaker trips or the pilot goes out, the whole system shuts down.

Thermostat or temperature sensor issues. A faulty thermostat can tell the heater to stop heating even when you need hot water. A quick test is to raise the temperature setting – if nothing changes, the thermostat is likely to blame.

Heating element or burner failure. In electric heaters, a broken heating element stops the water from warming up. In gas models, a clogged burner or bad igniter does the same. You may hear a clicking sound or see no flame.Build‑up of sediment. Over time, mineral deposits settle at the bottom of the tank. They act like an insulator, making the heater work harder and eventually overheat. When the safety valve trips, you lose hot water.

Leak or faulty pressure relief valve. A leak reduces water volume, and a stuck pressure relief valve can cause the tank to empty or shut off. Look for puddles around the heater or a constantly running valve.

Quick DIY Checks Before Calling a Pro

First, verify the power source. Flip the circuit breaker back on or reset the GFCI outlet. For gas units, check that the gas valve is open.

Next, inspect the pilot light. If it’s out, follow the manufacturer’s reset procedure – usually turning the knob to ‘pilot,’ holding it down while you press the igniter, then setting it to ‘on.’

Feel the tank. If it’s unusually hot on the top but cold at the bottom, sediment is likely the culprit. Flushing the tank once a year can prevent this. To flush, turn off the heater, attach a garden hose to the drain valve, open the valve, and let the water run until it’s clear.

Check the thermostat. Raise the temperature a few degrees and listen for a click. If you hear nothing, the thermostat may need replacement.

Finally, look for leaks. Tighten any loose fittings and replace worn‑out seals. If water pools around the base, the tank itself could be corroded and may need a full replacement.

If any of these steps feel beyond your comfort zone, or the heater still won’t produce hot water, it’s time to call a professional. A qualified tech can safely test heating elements, replace a broken thermostat, or diagnose gas line issues.

Keeping up with regular maintenance – flushing the tank, checking the pressure valve, and testing the pilot – can stop most water heater failures before they happen. A little attention now means fewer cold showers later.