You wipe the sleep from your eyes, turn on the shower, and wait for it to get warm. To your dismay, the water never warms up. Minutes later, the same chilly water is still shooting from your shower head, and you're left to wonder what's going on. Chances are, your hot water heater is not functioning properly. Follow these steps to identify the source of the problem and fix it, so you can enjoy warm showers again.
Step #1: Make sure your electric or gas supply is not to blame.
If you have an electric hot water heater, there's a chance an electrical outage during the night is to blame. Remember that it takes a while for the water in your water heater to cool down, so the power would have had to be out for a while to cause this problem. If your water is lukewarm but not hot and you think there may have been a power outage, wait 30 minutes or so to see if the water heats back up.
If you have a gas hot water heater, it's unlikely that an interruption in the gas supply is causing the issue. However, it's worth your while to make sure you paid the gas bill and that your gas wasn't shut off. It would be embarrassing to call your plumber about a broken hot water heater and find out you just forgot to pay the gas bill.
Step #2: Shut everything off.
To keep yourself safe while you're looking for the problem, make sure you turn off the water supply to your hot water heater. If you have an electric hot water heater, turn the electric supply to it off by flipping the correct switch on your circuit breaker. For a gas hot water heater, turn the gas control valve to the "pilot only" setting. Don't completely turn the gas off, since you'll want to look and make sure the pilot light is working.
Step #3a: Reset your circuit breaker if you have an electric hot water heater.
Sometimes an electric hot water heater may end up tripping the circuit breaker. If you discover that your circuit breaker is tripped when you go to turn it back on, flip the switch and see if your hot water heater starts working again. If it does, you've solved the problem. If the hot water heater flips the circuit again after you switch it back on, its electrical wiring is probably malfunctioning and you should call a plumbing repair company to diagnose and fix the problem.
Step #3b: Check the pilot light on a gas hot water heater.
For a gas hot water heater, peek at the pilot light and make sure it is lit. Sometimes a draft or breeze will blow out the pilot light. If the light is out, you can try relighting it in the same manner you would light a gas furnace pilot light. Use a long match or a long butane lighter to place a flame over the pilot. If it will not light, the pilot light valve may be damaged, and you should call a plumber to make the repairs.
If your pilot light is still lit, it's time to search for other possible explanations for the cold water.
Step #4: Check for crossed connections.
If cold water is mixing with your hot water after it is ejected from the water tank, this could explain why your water seems cold. Cross connections, which are places where the cold and hot water lines cross, can may occur it a valve within your plumbing breaks. Your hot water heater should already be turned off at this point. Thus, no water should come through if you turn on a hot water tap in one of your sinks. If cold water does come through the tap when you turn on the hot water faucet, a cross connection, rather than your hot water heater itself, is the source of your problem. You'll want to have a plumber come examine your system.
Tripped circuit breakers and blow-out pilot lights are common, simple explanations for cold water that you can address yourself. Most other problems, however, should be addressed by a plumber. Keep in mind that if your hot water heater is more than 10 years old, it may simply need to be replaced. The heating elements do tend to wear out eventually, and replacing them might cost just as much as buying a whole new unit.