American Water Heater water heater troubleshooting follows standard residential tank diagnostics. Because American Water Heater units are manufactured by A.O. Smith (parent company), the same fault patterns and remediation steps apply as for A.O. Smith (parent company)-direct units.
Symptom: No hot water
Electric models
- Verify breaker is on at the panel
- Press the high-limit reset on the upper thermostat. If it trips again within minutes, replace upper thermostat ($30, 30-min DIY)
- Test both elements with a multimeter (disconnect power first). Healthy: 10–16 ohms. Infinite = burned out
Gas models
- Verify pilot lit (sight glass or viewing window)
- If no pilot: follow lighting procedure on the unit
- If pilot won't stay lit: failed thermocouple ($20–40 part, $80–150 labor)
- If pilot lit but burner won't fire: gas valve failure or weak thermopile
Symptom: Lukewarm hot water
Lower element failed (electric) or burner orifice partially clogged (gas). Test lower element with multimeter. For gas, inspect burner for debris.
Symptom: Hot water runs out quickly
Cracked dip tube (year 7–12 failure) or both elements working at half-capacity (uncommon). Pull dip tube, inspect, replace if cracked ($10 part, 30 minutes).
Symptom: Water around base
Diagnose in order: T&P discharge, drain valve weep, dielectric union, anode rod port, then tank weld. Tank weld leaks = warranty claim, tank replacement required.
Symptom: Popping or rumbling
Sediment accumulation. Annual flush; severe cases require full drain-and-flush with a sediment-removal nozzle.
Symptom: Rotten-egg smell in hot water
Sulfur reduction by magnesium anode reacting with bacteria. Replace magnesium anode with aluminum-zinc alloy ($30–45). Sanitize tank with 3% hydrogen peroxide if persistent.
Symptom: T&P valve continuously discharges
Three possibilities: failed T&P valve (replace), thermal expansion pressure spike (recharge expansion tank), or runaway thermostat (replace thermostat or gas valve).
When to call a pro
Gas valve replacement, tank weld leaks, or any electrical issue beyond standard element/thermostat replacement. A.O. Smith (parent company)-authorized service technicians have specific training and parts access; local plumbers familiar with the underlying manufacturer can also handle most repairs.