4 Reasons Your Water Heater Won’t Stay On

Few things are as frustrating as your water heater not staying on to produce enough hot water for your household’s needs. We don’t realize how much we rely on our water heaters until the hot water isn’t there when we need it.

Several things could be causing your water heater to experience problems, and they vary depending on whether your unit is gas or electric. For example, many gas water heaters contain a thermocouple device, while electric units do not.

You need to know whether your water heater is gas or electric to troubleshoot the problem of your water heater not staying on.

Pipes connected to the water heater indicate it’s a gas unit.  A gas water heater will also have an access panel on the side with the pilot light underneath it. An electric unit will only have a cord coming from it to plug it in.

Here are four possible reasons your water heater won’t stay on:

1. A malfunctioning thermocouple on a gas water heater.

A thermocouple is a device that shuts off the gas if the pilot light goes out on a gas water heater to prevent gas buildup, and it’s an important safety feature. It’s a small thermoelectric probe that allows the gas valve to stay open whenever the pilot light is lit.

The thermocouple sits over the pilot flame, and if it malfunctions, it may be unable to sense that the pilot light is on. If necessary, you’ll be able to relight the pilot light, but the water heater won’t stay on if the thermocouple isn’t working.

The thermocouple will stop the gas supply to the burners that heat the water if it isn’t sensing heat from the pilot light.

The problem could be a bent wire that’s leaning too far away from the pilot light to sense it, or there could be dust or dirt on the thermocouple.

As the problem involves gas, you’re best-off leaving repairs to a professional.

Chas Roberts can determine if you have a problem with the thermocouple on your gas water heater, and if so, they can fix it.

2. A faulty thermostat or heating coil.

If the thermostat on your water heater isn’t working correctly, the water in the tank could be getting too hot.

When the water temperature in the tank reaches over 180 degrees Fahrenheit, the reset button will shut off the power to the unit as a safety measure. Otherwise, scalding hot water could flow through the tap, causing injuries.

If you keep having to push the reset button on your unit to get any hot water, you may have a thermostat problem. You shouldn’t have to reset your water heater regularly, and the thermostat isn’t keeping the water at a safe, consistent temperature if you do.

Newer electric water heaters have two separate heating elements, but only one element is active at a time. Dual element water heaters provide an efficient water heating system and heat water more quickly than a single element unit. Two thermostats control water temperature on a dual element water heater.

A single element water heater only heats water from the bottom up and has one thermostat.

You’ll have no hot water at all if the thermostat fails in a single element water heater. In a dual element unit with two thermostats, you may still have a limited amount of hot water if the lower thermostat goes out, but none if the upper thermostat fails.

An electric water heater may keep shutting off because it’s tripping the electrical breaker. If the breaker keeps shutting down every time you need hot water, you have an electrical problem that needs to be addressed, possibly a short in the breaker.

A bad heating element in your unit may also be the source of your water heater’s problem. If your water heater keeps shutting down, a component may be failing in the unit.

You can test your electric water heater’s upper and lower elements with an electrical tester, but you should contact a professional for any needed repairs.

3. A problem with the water heater’s power source.

Your gas water heater needs a steady supply of gas to heat the water and may not be getting enough gas due to a leak or problem with a gas valve.

It’s not a good idea for homeowners to attempt to diagnose or fix problems related to gas themselves. You should call a professional to address any suspected gas leak or gas flow problems with your water heater for safety.

Electric water heaters need to be securely plugged in with access to a dedicated live breaker.

If there’s a problem with your unit’s gas or electrical power source, it most likely won’t stay on. Even a well-functioning water heater can’t keep working efficiently with an undependable power source.

4. Age

The lifespan of a water heater is roughly ten years, and if your unit is older than ten years, its reliability is no longer predictable.

Your unit probably has failing parts that are preventing the water heater from staying on.

Even with regular maintenance extending the life of your water heater, an older unit that won’t stay on is due for replacement. Buying a new water heater is more cost-effective than spending money on parts to repair an older unit.

Chas Roberts can install a new, reliable, more energy-efficient water heater in your home.


These are some possible reasons your water heater isn’t working properly and won’t stay on.

We need our water heaters to provide us with hot water we can count on.

Regular maintenance can prevent problems and extend the life of our water heaters, but even a well-maintained unit may need repairs at some point.

Eventually, though, replacing rather than repairing an older failing unit that won’t stay on becomes the most sensible option.

Chas Roberts

Chas Roberts is the largest HVAC and plumbing provider in Arizona.  We’ve been family-owned and operated for over 75 years and have the highest skilled technicians in the industry.  Contact us for reliable, quality service at affordable prices.