By the Peoria AZ Plumbing Co team · Published 2026-07-27 · Updated 2026-09-13
Before assuming your water heater has failed entirely, check the obvious first: on a gas unit, confirm the pilot is lit and the gas supply is on; on an electric unit, check the breaker and any reset button on the thermostat. Both of these cause a total loss of hot water and are quick, free fixes when they are the actual cause. If those check out and you still have no hot water, the more likely culprits are a failed thermocouple, gas valve, heating element, or thermostat, all of which are repairable rather than requiring a full replacement.
Dealing with this right now? This guide covers the background. For the actual repair, our Water Heater Repair page has what to expect from a visit, or call (623) 323-3182 to talk it through directly.
Gas water heaters: pilot, thermocouple, gas valve
If the pilot light is out, most units have a straightforward relighting process printed on the tank itself, and following it is safe if you can smell no gas beforehand. If the pilot will not stay lit after relighting, a failed thermocouple is the most common cause, and it is an inexpensive, quick repair.
If the pilot is lit and staying lit but the burner will not fire, the gas valve itself may have failed, which is a less common but still repairable issue rather than a reason to replace the whole unit.
Electric water heaters: breaker, elements, thermostats
Check the breaker panel first; a tripped breaker is the simplest explanation and costs nothing to fix. Many electric water heaters also have a high-temperature reset button on the upper thermostat that can trip and cut power to the unit without tripping the main breaker.
If power is confirmed reaching the unit and you still have no hot water, one of the two heating elements or thermostats has likely failed. Electric tanks typically have an upper and lower element, so a failure in just one can sometimes leave you with lukewarm rather than fully cold water instead of a total loss.
When it is scale, not a failed part
Popping or rumbling from the tank is sediment settling at the bottom and interfering with heating, common given how hard Peoria's water runs. This usually reduces efficiency and hot water output rather than causing a total loss, and a flush often resolves it.
If your water has become discolored alongside reduced hot water, that can point to either sediment or a consumed anode rod allowing the tank itself to begin corroding internally.
When it is genuinely time to call rather than troubleshoot further
Any water pooling at the base of the tank means the tank has failed structurally and needs replacement, not repair, regardless of what else might also be wrong. A gas smell at any point means stop troubleshooting immediately, leave the area, and call the gas utility from a safe distance before doing anything else.
If you have checked the obvious and are still unsure, describing what you have already tried to a plumber over the phone often narrows down the likely cause before anyone even arrives.
The bottom line
Most total losses of hot water trace back to one of a handful of common, repairable causes rather than requiring a full replacement, which is worth remembering before assuming the worst.
The main exception is a tank that is visibly leaking from its body, which is the one symptom that means replacement rather than repair regardless of what else checks out fine.
What to tell a plumber over the phone
Before calling, note whether the unit is gas or electric, whether you have already checked the breaker or pilot, and whether the loss of hot water was sudden or gradual, since all three details help narrow down the likely cause before anyone arrives.
Mentioning any unusual sounds, smells, or visible water around the unit also helps a plumber arrive prepared with the right parts rather than needing a second visit once the actual cause is confirmed on site.
| Fuel type | Check first | If that's fine, likely cause |
|---|---|---|
| Gas | Pilot lit? Gas supply on? | Thermocouple or gas valve |
| Electric | Breaker tripped? Reset button popped? | Heating element or thermostat |
| Either | Popping/rumbling noise? | Sediment buildup, needs a flush |
| Either | Water pooling at the base | Tank has failed, needs replacement |
Frequently asked questions
Is it safe to relight a gas pilot myself?
If you smell no gas and the unit has clear relighting instructions printed on it, yes. If you smell gas at any point, stop immediately, leave the area, and call the gas utility rather than continuing.
Why do I have lukewarm water instead of no hot water at all?
On an electric unit, this often means one of the two heating elements has failed while the other still works, giving you some heat but not enough for full demand.
How do I know if it's the thermostat or the heating element?
Both produce similar symptoms and are difficult to distinguish without testing, which is one reason this particular repair is often better handled by a plumber with the right meter rather than guessed at.
Can hard water actually cause a total loss of hot water?
Rarely on its own, though severe scale buildup can eventually interfere with a burner or element badly enough to reduce output significantly. A total, sudden loss is more often a specific failed component.
Should I try to diagnose this myself or just call a plumber right away?
Checking the pilot, gas supply, and breaker takes only a minute and rules out the two most common causes at no cost. Beyond that, a plumber's diagnostic tools identify the specific failed component faster than continued guessing.
Is it normal for a water heater repair to require a follow-up visit?
Occasionally, if a part needs to be special-ordered or if the initial diagnosis reveals a second issue only visible once the first is addressed. A good plumber should explain upfront if they suspect this might be the case, rather than letting you assume a single visit will definitely resolve everything.
Could a recent power outage be the reason my electric water heater isn't working?
Yes, some electric water heaters need the high-temperature reset button manually pressed after a power interruption, even if the breaker itself never tripped, so check that reset button specifically after any recent outage.
Could low water pressure be mistaken for a hot water problem?
It is possible to conflate the two if a pressure issue happens to affect the hot side more noticeably, though a true loss of heat versus a loss of flow are diagnosed differently, so describing the symptom precisely helps a plumber troubleshoot correctly.
Reviewed by the Peoria AZ Plumbing Co team. Our work follows the International Plumbing Code (IPC) and the International Fuel Gas Code (IFGC) as adopted regionally, plus the permit and inspection requirements of the City of Peoria and Maricopa County.