Heating element failure is the most common Rheem electric water heater service item. Elements last 6–10 years depending on water hardness; once one fails, replacement is a 60-minute job for any handy homeowner with a multimeter. Total parts cost: $30–$60.
Symptoms of element failure
- Upper element failed: no hot water at all (the upper element is what fires first; if it's dead, neither tank heats)
- Lower element failed: hot water at first then quickly lukewarm (upper element keeps top of tank hot but can't keep up as you draw)
- Both elements failed: no hot water and breaker keeps tripping (rare; usually means lightning strike or sustained over-voltage event)
Rheem element part numbers
| Element | Rheem part # | Voltage / wattage |
|---|---|---|
| Standard 4500W (Performance, Performance Plus electric) | SP10874MN | 240V 4500W screw-in |
| Standard 5500W (high-recovery variants) | SP10874MK | 240V 5500W screw-in |
| Low-wattage 3800W (mobile-home spec) | SP10874LH | 240V 3800W screw-in |
| Marathon polybutene-compatible element | AP12932A | Specialized — Marathon line only |
| ProTerra backup element | SP21176B | 240V 4500W |
Universal-replacement 4500W screw-in elements (from Camco, Reliance, etc.) work in Rheem tanks. Verify the screw-in threading matches before ordering — most modern Rheem use 1" or 1-1/4" NPT screw-in.
How to test which element failed
You need a multimeter set to ohms.
- Shut off power at the breaker. Verify with a voltage meter at the element terminals.
- Remove the access panel covering the element you're testing (upper or lower)
- Disconnect the two element wires from the element terminals
- Set multimeter to ohms (200 ohm range)
- Touch the probes to the two element terminals
- Reading 10–16 ohms: element is good
- Reading 0 or "OL" / infinite: element has failed — replace
- Reading 1–9 ohms: element is shorted — replace
Also check that the element terminals don't show resistance to ground (touch one probe to the tank metal, the other to each element terminal — should be infinite/OL). If you see resistance to ground, the element has shorted to the tank and the high-limit breaker may have been tripping.
Replacement step by step
- Shut off power, verify with meter
- Shut off cold-water inlet
- Open a hot-water faucet in the house
- Drain the tank to below the element you're replacing (upper element: drain about half the tank; lower element: drain the entire tank). Use a garden hose on the drain valve to a floor drain or outside.
- Remove the access panel and the insulation around the element
- Disconnect the element wires
- Unscrew the element with a 1-1/2" element wrench (~$15 at any hardware store — don't try to substitute another tool, you'll round the element and make it harder to remove)
- Pull the element straight out — there's a rubber gasket on the threaded base
- Install the new element with a fresh gasket (usually included with the new element), hand-thread first, torque to ~25 ft-lbs (snug + 1/4 turn)
- Reconnect wires (no specific polarity)
- Refill the tank — open cold inlet, run hot-water faucet until steady flow
- Restore power only after the tank is full — running an exposed element with no water destroys it in seconds
Common mistakes
Powering up before refilling: the #1 mistake. Burns out the new element instantly. The tank must be completely full of water before power restoration.
Using regular socket or pliers instead of an element wrench: rounds the hex on the element base and turns a 60-minute job into a 4-hour job.
Cross-threading the new element: hand-thread first. Resistance after 1–2 turns means you're cross-threaded; back out and restart.
Skipping the new gasket: the rubber gasket is single-use. Reusing an old gasket guarantees a slow leak you won't notice for 6 months.
4500W vs 5500W upgrade
If your panel and circuit support 5500W (most do — 30-amp 240V circuit is standard), upgrading from 4500W to 5500W speeds recovery by ~22%. Same physical install. Worth it for high-demand households.
Bottom line
Element replacement is the most common Rheem electric service item — and one of the most DIY-friendly. Total cost: ~$50 parts + an hour of work, vs $200–$350 for a service call. Element wrench at the hardware store is the only specialty tool. For other parts see our Rheem parts directory.