How to Replace a Heating Element in a Hot Water Tank: A Laguna Hills, CA Guide
Swapping a heating element is one of the more doable water heater repairs. This guide walks through the steps and shows where a homeowner should stop and call a plumber.
This guide is for an electric tank water heater with two screw in or bolt in elements. Gas heaters, hybrid models and tankless units use different parts. If you are not sure what you have, read the label on the tank.
Replacing an element involves line voltage and a full tank of very hot water. If any step feels unsafe, stop and book a plumber.
What you need
- A replacement element with the same wattage, voltage and mount style.
- An element wrench or a deep socket that fits.
- A non contact voltage tester and a multimeter.
- A garden hose and a bucket for draining.
- A flat screwdriver, gloves and eye protection.
Check the data plate on the tank for the rated wattage and voltage. A common electric tank uses 240 volt, 4,500 watt elements. A 4,500 watt, 240 volt element reads around 13 ohms on a meter when it is healthy.
Step by step
Power off
Switch off the breaker for the heater. Test the wires with a tester to be sure they are dead.
Water off
Close the cold water valve and open a hot tap in the house to let air in.
Drain
Connect a hose to the drain valve and drain the tank below the element you are changing.
Open
Remove the access panel and insulation, then the plastic cover over the thermostat and element.
Disconnect
Take a photo of the wiring, then remove the wires from the element terminals.
Remove
Unscrew the old element with the wrench and pull it out.
Install
Fit the new gasket and element and tighten it firmly without overtightening.
Refill
Close the drain, open the cold valve and let water run from the hot tap until it flows steadily.
Restore
Reconnect the wires, replace covers and insulation, then switch on the breaker.
Do not skip the refill step. A dry element burns out within seconds when power is applied, and it will not carry a warranty claim.
Testing the old element
A multimeter confirms a bad element before you buy a new one. With power off and wires removed, set the meter to ohms and touch the two terminals. A reading near the expected value means the element is good. No reading means it has burned out.
Also touch one probe to a terminal and the other to the metal mount. Any reading means the element is shorted to ground, and that is the cause of a tripped breaker.
Want a plumber to do it?Call and we will replace the element.
Call (949) 325-3122Mistakes that cause trouble
| Mistake | What happens |
|---|---|
| Power on before refill | The new element burns out within moments. |
| Wrong wattage or voltage | Poor heating or a tripped breaker. |
| Overtightened element | The mounting threads or the gasket seat can be damaged. |
| Forgot to drain below the element | Water pours out as the element comes loose. |
| Ignored sediment | The new element fails early in the same scale. |
After the repair: thermostat and testing
Set the thermostat to about 120 degrees Fahrenheit unless your household needs more. A lower setting reduces scald risk and saves energy. Give the tank time to heat, and test the water at a tap after an hour or two.
If the unit has a red reset button on the upper thermostat, press it once after the repair. A tripped limit switch can look like a failed element.
Laguna Hills notes: checks to make while the tank is open
The City of Laguna Hills water heater handout is a good checklist to run through during any service call. It asks for a temperature and pressure relief valve with a discharge line piped to a safe place, a drain pan where leakage could do damage, and seismic straps in the upper and lower thirds of the tank.
A repair that replaces only a part is different from a replacement of the heater. The Laguna Hills Building & Safety Division, at (949) 707-2600, can say whether a permit applies to what you are doing. Electrical work should follow the National Electrical Code (NEC).
Sources: City of Laguna Hills water heater handout (2022 California Plumbing Code), Laguna Hills Building & Safety Division.
When to stop and call
Signs the job is not just an element
- Water around the base of the tank or on the floor.
- Rust colored water that does not clear.
- A tank that is more than a decade old and has heavy sediment.
- Burn marks, melted wire insulation or a breaker that trips again.
- A heater in a Village manor, where approvals apply.
If the tank is failing, water heater replacement may be the better path. In Laguna Woods and Laguna Niguel, local rules also apply.
Local questions, answered
How do I know I have the right replacement element?
Match the wattage, voltage and mount style printed on the old element or on the tank label. The mount can be a screw in thread or a four bolt flange.
Can I replace the element without draining the tank?
No. The element sits inside the tank, so water must be drained below it first.
Does replacing an element need a permit in Laguna Hills?
It is a repair to a part, but ask the Building & Safety Division at (949) 707-2600 if you are unsure.
Why did my new element fail in a week?
The usual causes are a dry fire from skipping the refill, heavy sediment around the element or the wrong voltage.
Want a plumber to do it?
Call and we will replace the element.