How do I know if my water heater heating element is bad?

How an electric water heater heats

Most residential electric tanks have two screw-in elements, one near the top and one near the bottom, each controlled by its own thermostat. In the usual setup only one element runs at a time. When the tank is cold, the upper element heats the top first. Once the top is hot, power moves to the lower element, which then does most of the day-to-day work as cold water enters at the bottom^[3].

Each element has its wattage and voltage stamped on its terminal block, for example 4500 W at 240 V^[3]. That rating matters: a replacement must match what the heater's data plate allows.

Symptoms of a failed element

Symptom	Likely element problem	Notes
No hot water at all	Upper element burned out	Also check the breaker and high-limit[3]
Steady lukewarm water	Upper element	HomeGuide's pattern[1]
Hot water runs out quickly	Lower element	Can also be a dip tube or an undersized tank[1][3]
Slow recovery	Lower element, or scale on the elements	[3]
Breaker trips when the heater calls for heat	Element shorted to ground	[3]
High-limit (red reset button) keeps tripping	Usually a grounded element that keeps heating	[3]
Singing or hissing from the tank	Lime formation on the elements	[3]

Why elements fail. Bradford White lists three common causes^[3]:

1. Dry firing. The element runs with no water around it, usually because power came on before the tank was full. Sediment can also trap an air pocket around an element. Either way it fails within seconds.
2. Grounded element. The element shorts to the tank. That usually trips the breaker. If it does not, the element can keep heating until the high-limit cuts power, which is why repeated high-limit trips usually trace back to a grounded element.
3. Sediment buildup. Scale around the lower element slows recovery and can eventually cause a dry fire.

HomeGuide adds that sediment at the bottom of the tank corrodes the lower element, and that yearly flushing helps it last^[1].

What a homeowner can safely check

• The breaker. Electric tanks run on a 240-volt double breaker. If it tripped, reset it once. If it trips again, stop and call. See breaker keeps tripping.
• Symptoms and timing. No hot water versus lukewarm versus runs out fast tells the plumber where to start.
• Recent events. A tank that was drained, a power outage, or recent work on the heater.
• Noise. Hissing or singing points to scale on the elements.
• Water near the access panels. If water has reached the wiring, turn the breaker off and call.

Do not remove the access panels or test elements yourself. Bradford White's own testing steps involve measuring live line voltage at the thermostat terminals, and its manual is labeled for qualified service providers only^[3]. Rheem says not to turn the heater on unless it is filled with water^[5].

What the pro does

A licensed plumber or electrician will typically:

• Confirm power reaches the heater and that the high-limit has not tripped^[3].
• Test each element for resistance with the power off. The expected value comes from the rating, for example about 12.8 ohms for a 4500 W, 240 V element^[3].
• Test each element for a short to the tank. Any reading means the element must be replaced^[3].
• If an element is bad: shut off power and water, drain the tank below the element, replace it with one that matches the data plate, refill and purge all air, then restore power.

That last step is the one that matters most. A.O. Smith says the tank must be completely full and purged of air before power is connected, and that a dry-fired upper element is an installation error not covered under warranty^[4].

What it costs

Source (date)	Item	Range
HomeGuide (Aug 2025)	Heating element replacement, installed	$100 to $350[1]
Modernize (Aug 2026)	Element replacement, one or both, including drain and refill	$150 to $350[2]
Modernize (Aug 2026)	Diagnostic or service call	$75 to $200[2]

HomeGuide notes minimum service call fees of $50 to $200 may apply^[1]. Element jobs are among the lower-cost water heater repairs, so they usually make sense on a sound tank.

Repair or replace?

An element is cheap to replace on a tank in good shape. Rheem's rule of thumb: repair units under about 6 to 8 years old with one failed part, and replace when a repair costs more than 50% of a new unit^[6]. If the tank is near the end of its life, or if the element failed because the tank is full of sediment, a replacement may be the better buy. Check the build date with our age decoder.

When to call a pro

• The breaker trips again after one reset.
• The high-limit keeps tripping, or the water is hotter than normal.
• No hot water, or hot water that runs out fast, with the breaker on.
• Any testing or replacement of an element, which means working on 240-volt wiring.