How to Test a Water Heater Element
A water heater element test takes a multimeter set to ohms and about as long as it takes to remove two access panels. With the power off and the wires disconnected, a good element shows a resistance close to its rated value, a burned-out one shows no reading at all, and one that's shorted to the tank shows a reading between a terminal and the metal flange.
Test both elements, upper and lower. They fail independently, and the symptoms overlap enough that guessing wastes a part.
What you need
- A digital multimeter with an ohms (Ω) setting. A cheap one is fine.
- A non-contact voltage tester, or the multimeter on AC volts, to prove the power is off.
- A screwdriver for the access panels and terminal screws.
- Your heater's rating plate, which lists the element wattage and voltage.
What a good reading looks like
Bradford White's service manual gives the formula: ohms equals volts squared divided by watts. For a 240-volt, 4500-watt element that's 12.8 ohms, and Bradford White says the reading should fall within 6% of that. Outside that range, replace the element.
Here are the targets for common elements, worked out with that formula:
| Element rating | Target resistance |
|---|---|
| 3500 W at 240 V | About 16.5 ohms |
| 4500 W at 240 V | 12.8 ohms |
| 5500 W at 240 V | About 10.5 ohms |
| 4500 W at 208 V | About 9.6 ohms |
You don't need to hit the number on the nose. A reading in the right neighborhood means the coil is intact. The readings that matter are the extremes: nothing at all, or close to zero.
Step by step
Turn off the breaker
for the water heater. It's a double breaker on most panels.
Remove the upper access panel
, fold back the insulation and pull off the plastic guard if there is one.
Check for voltage
Touch your tester to the element terminals and to the thermostat terminals. You want nothing. If you get a reading, you've got the wrong breaker.
Disconnect one wire from the element
Bradford White's procedure disconnects the element wires before testing. If you leave both on, the meter reads through the rest of the circuit and the number means nothing.
Set the meter to ohms
and touch one probe to each element terminal screw. Write down the reading.
Test for a ground
Put one probe on a terminal screw and the other on the element's metal flange or a bare spot on the tank. Bradford White says any reading means the element is grounded and must be replaced. Repeat for the other terminal.
Reconnect the wire
, put the guard and insulation back, and repeat the whole thing on the lower element.
Reading the results
| What the meter shows | What it means |
|---|---|
| Close to the rated value | The coil is good |
| No reading (open line or "OL") | Burned out. The coil has broken inside |
| Far outside the rated range | Bad. Replace it |
| Any reading from terminal to flange | Grounded. Replace it |
A grounded element is the one people miss. It can still read a normal resistance across its terminals and heat the water, but it can also trip the breaker or the red reset button. A.O. Smith lists a grounded heating element as a common reason the reset button trips, and State's troubleshooting chart lists it as a cause of water that's too hot.
Scale tells its own story. If you hear crackling or popping from the tank, A.O. Smith says that's scale forming on the elements. The element may test fine and still be worth replacing once it's coated.
Testing without a multimeter
You can't properly test an element without some kind of meter. There are two other ways to narrow it down, both less certain.
The first is a clamp-on ammeter. State's handbook lists a continuity or amperage check for a burned-out element. With the heater running, a clamp meter around one element wire should show current. A 4500-watt element at 240 volts draws about 18.75 amps. Zero amps while the thermostat is calling for heat means a dead element. This test is done with the power on, so it's for people who know their way around live circuits.
The second is the symptom check. No hot water at all usually points to the upper element or thermostat. Hot water that runs out fast points to the lower element, and HomeGuide lists that as a sign of a faulty lower element. It narrows things down. It doesn't prove anything.
Mistakes to avoid
- Testing with the wires still connected. You'll read the thermostat and the other element too.
- Skipping the ground test. It's the reading that catches the element that's tripping your breaker.
- Testing one element and stopping. Check both.
- Forgetting to prove the power is off. Breakers get mislabeled.
What to do with the result
If an element tests bad, replace it. Our guide to replace a water heater element covers draining, the socket you need and how to avoid burning out the new one.
If both elements test good and the reset button isn't tripped, the thermostat is the next suspect. See the water heater thermostat page for testing and settings.
When it's a pro job
Call a plumber or electrician if you find scorched wires, melted terminals, or a breaker that trips the instant it's reset. Also call if you'd rather not open panels on a 240-volt appliance. HomeGuide puts a professional element replacement at $100 to $350, and the tech will test the thermostats while they're there.
FAQ
How do you test a water heater element?
Turn off the power, disconnect the element wires and set a multimeter to ohms. Touch the probes to the two terminal screws and compare the reading to the rated value, which Bradford White puts at 12.8 ohms for a 4500-watt, 240-volt element. Then check from each terminal to the metal flange to rule out a ground.
How do I check the heating element on a water heater without taking it out?
You test it in place. The element stays in the tank and full of water; you only remove the access panel and one wire. There's no need to drain anything unless the element turns out to be bad.
How do I check both elements on a water heater?
Test them one at a time with the same steps. Disconnect a wire on the upper element, measure, reconnect, then do the lower one. They're independent, so one can be dead while the other is fine.
What does it mean if my element reads zero ohms?
A reading near zero means the coil is shorted. Bradford White's rule is that a reading outside the rated range means replace the element. Run the ground test at the same time.
Sources
- Bradford White CorporationResidential Electric Water Heater Service Manual 238-51544-00 (opens in a new tab)
- State Water HeatersResidential Electric Water Heater Service Handbook (320990-000) (opens in a new tab)
- A. O. SmithWater Heater Not Working? Troubleshooting Guide (opens in a new tab)
- HomeGuideHow Much Does Water Heater Repair Cost? (2026) (opens in a new tab)