No Hot Water? Troubleshoot It Before You Call a Plumber
No hot water usually traces to a few specific failures by water-heater type: on gas units it’s typically a pilot light or gas issue; on electric units it’s a tripped breaker, a tripped reset button, or a failed heating element or thermostat. Many “no hot water” calls are something you can check in five minutes. Knowing whether you have gas or electric — and where the reset and shutoffs are — tells you what to look at first. Here’s the troubleshooting order.
First: Gas or Electric?
The cause and the checks differ completely:
| Type | Most common no-hot-water causes |
|---|---|
| Gas | Pilot light out, gas supply off, bad thermocouple, gas control valve |
| Electric | Tripped breaker, tripped high-limit reset button, failed element or thermostat |
| Either | Wrong/low thermostat setting, leaking/failed tank, pilot reset after gas interruption |
If You Have an Electric Water Heater
- Check the breaker — water heaters have a dedicated double breaker; reset it if tripped (if it trips again, stop and call a pro).
- Press the reset button — there’s a red high-limit reset on the upper thermostat behind an access panel; press it. If it keeps tripping, the element/thermostat may be failing.
- Check the thermostat setting — typically ~120°F.
- Lukewarm only / runs out fast — often a failed lower element; that’s a pro fix.
Caution: don’t remove access panels without shutting off the breaker first — these terminals are live.
If You Have a Gas Water Heater
- Check the pilot light — if it’s out, relight per the instructions on the tank (or use the igniter). Many newer units have a status light.
- Confirm gas is on — the supply valve and that other gas appliances work.
- Pilot won’t stay lit — usually a thermocouple (cheap part) or gas control valve; a pro job.
- Smell gas? Stop — leave and call the gas company. Don’t troubleshoot.
When It’s Time to Call a Plumber
- Breaker or reset that keeps tripping (electric).
- Pilot that won’t stay lit / no gas at the unit.
- Lukewarm or quickly-depleted hot water (element/dip tube/sediment).
- Any leak from the tank — that’s often replacement.
| Work | Typical cost |
|---|---|
| Thermocouple (gas) | $150 – $350 |
| Heating element/thermostat (electric) | $200 – $400 |
| Tank flush (sediment) | $100 – $250 |
| Water heater replacement | $1,200 – $3,500+ |
If the unit is old or leaking, weigh repair vs. replacement, and if a quote seems off, see plumber quote seems high. General pricing: water heater repair cost.
Frequently Asked Questions
Why do I suddenly have no hot water? It depends on your water heater type. On gas units the pilot light is often out or the thermocouple/gas valve failed. On electric units, a tripped breaker, a tripped reset button, or a failed heating element or thermostat is usually to blame. A wrong thermostat setting or a failed tank can affect either type.
How do I reset my electric water heater? Behind the upper access panel there’s a red high-limit reset button — press it after shutting off the breaker for safety. Also check that the dedicated double breaker in your panel hasn’t tripped. If the reset or breaker keeps tripping, an element or thermostat is likely failing and needs a pro.
My gas water heater pilot light won’t stay lit — why? The most common cause is a faulty thermocouple, the sensor that confirms the pilot flame and keeps gas flowing; it’s an inexpensive part to replace. A dirty pilot or a failing gas control valve can also be responsible. If you smell gas, stop troubleshooting, leave, and call the gas company.
Why is my water lukewarm or running out fast? On electric heaters, a failed lower heating element commonly produces lukewarm water, while sediment buildup or a broken dip tube reduces capacity so hot water runs out quickly. These usually need a plumber to test elements, flush the tank, or replace parts. An aging tank may be near replacement.
Should I repair or replace a water heater with no hot water? If it’s a cheap fix like a thermocouple, element, or thermostat on a unit under about 8–10 years old, repair it. If the tank is leaking, old, or facing repeated failures, replacement usually makes more sense. Compare the repair cost against a new unit and the heater’s age.
Last updated: June 16, 2026. Sources: U.S. Department of Energy water-heater guidance; standard gas/electric water-heater troubleshooting practice; 2026 cost ranges per our plumbing guides. Shut off power before opening electric panels; if you smell gas, leave and call for help.