You have no hot water
The answer forks on whether your heater is electric or gas - check that first.
Is this an emergency?
Not an emergency, but don’t leave it a season.
You’re probably seeing
- No hot water at any tap, anywhere in the house
- Hot water that runs out far faster than it used to
- Water that is lukewarm but never properly hot
- Hot water at some taps but not others
- A gas heater whose pilot light will not stay lit
What it probably is
Electric: a tripped high-limit reset
The most common electric cause, and free to reset onceNo hot water at all, suddenly. Behind the upper access panel there is a red reset button; if it has popped, that is your answer.
Gas: the pilot light is out or the thermocouple has failed
The most common gas causeNo hot water at all and no flame visible through the sight glass. If the pilot lights and then dies when you release the control, the thermocouple is the usual culprit.
A failed heating element
Common on electric heaters over about five yearsElectric only. A failed upper element gives no hot water at all; a failed lower element gives a small amount of hot water that runs out very quickly.
A failed thermostat
Common, and easily confused with an elementWater that is lukewarm but never hot, on either fuel type, with no other symptoms.
Sediment build-up in the tank
Common, and gradual rather than suddenHot water capacity has fallen gradually over months, and the tank rumbles or pops while heating. Common in hard-water areas.
A tripped breaker or a closed valve
Less common, but free to rule outCheck the obvious. A breaker for the heater, or a partly closed shut-off after recent plumbing work.
What to do before anyone arrives
Establish which kind of water heater you have
Look for a gas line and a burner access cover near the floor with a flame sight glass, or a pair of metal access panels on the side of the tank with no gas line. Everything after this step depends on the answer, and a tankless unit changes it again.
Check the breaker or the gas supply
Electric heaters usually sit on a dedicated double-pole breaker. Reset it once if it has tripped. On gas, confirm the supply valve is open and that other gas appliances in the house are working.
If the breaker trips again straight away, leave it off - that is a fault being reported, not a nuisance trip.
Electric only: look for the high-limit reset button
Switch the breaker off first. Remove the upper access panel and fold back the insulation. There is a small red button - if it has popped out, press it firmly until it clicks. Replace the insulation and panel before restoring power.
Kill the breaker before removing any panel. There is line voltage behind it. If the reset trips again, stop - a repeatedly tripping high limit means a failing element or thermostat, not a button that needs pressing harder.
Gas only: check whether the pilot is lit
Look through the sight glass near the bottom of the tank. If there is no flame, follow the relighting instructions printed on the label on the side of the heater - they are model-specific and worth following exactly.
If you smell gas at any point, stop, leave the house and call the gas utility from outside. Do not try to relight anything.
Check the thermostat setting, but do not raise it above 120°F
Confirm it has not been knocked down. The CPSC urges households to set water heaters to 120°F, and that is also the right ceiling while troubleshooting - raising the temperature to compensate for a fault creates a scald risk without fixing anything.
Note the age and symptoms, then call
The manufacture date is on the rating plate. Whether the failure was sudden or gradual, and whether you get no hot water or a little, tells a plumber a great deal before they arrive.
This is the end of the homeowner sequence. Elements, thermostats, gas valves and thermocouples are all live-system work on a pressurised tank.
What it costs to fix
Ranges below are for the repair itself. For full replacement pricing see the plumbing cost guides.
| What it is | Repairable? | What decides your bill |
|---|---|---|
| Tripped high-limit reset (electric) | Free, if it holds | Nothing - but a repeat trip is a real fault |
| Tripped breaker | Free | Nothing, unless it trips again |
| Thermocouple (gas) | Yes - an inexpensive part | Mostly the call-out and labour |
| Heating element (electric) | Yes - an inexpensive part | Labour, plus draining the tank to reach it |
| Thermostat | Yes - an inexpensive part | Mostly the visit |
| Sediment flush | Yes - maintenance, not a repair | Labour and time, and it may not restore a badly scaled tank |
| Tank corroded or beyond its life | No | A replacement conversation, not a repair |
U.S. Bureau of Labor Statistics, Occupational Outlook Handbook (May 2025 wage data).
The pattern here is that almost every common cause is a cheap part and a moderate amount of labour - so on a no-hot-water call the bill is mostly the visit. That is legitimate and worth knowing before you are quoted. Labour anchor: the national median wage for plumbers, pipefitters and steamfitters is $30.67 an hour (BLS, May 2025), billed on top of a call-out. We do not print a national installed replacement price, because fuel type, venting and local labour move it more than any average can carry.
Can I fix this myself?
Behind the access panels of an electric water heater is line voltage, and it is not obviously live - kill the breaker before removing anything. On a gas heater, if you smell gas, leave the building and call from outside rather than investigating. And do not raise the thermostat above 120°F to compensate for poor hot water: CPSC records third-degree burns from a six-second exposure at 140°F and a thirty-second exposure at 130°F.
Reasonable to DIY
- Identifying whether the heater is gas or electric
- Resetting a tripped breaker once
- Pressing a popped high-limit reset once, with the power off
- Relighting a gas pilot using the label instructions
- Checking the thermostat has not been knocked below 120°F
Call a pro
- Replacing heating elements or thermostats
- Replacing a thermocouple or gas control valve
- Diagnosing a high limit that keeps tripping
- Draining and flushing a heavily scaled tank
- Any tankless unit fault beyond a filter clean
Two of the most common causes on this page - a tripped breaker and a popped high-limit reset on an electric heater - cost nothing and take five minutes, and a great many paid call-outs turn out to be exactly that. Press the reset once. If it trips again, that is the heater telling you something is genuinely failing, and the rest of the list is a plumber job.
Is this covered by insurance?
Whether a claim is worth filing depends on the cause, your deductible and how the damage happened - not on the repair price alone.
Sources
Sources last checked
- Tap Water Scalds (CPSC Publication 5098)U.S. Consumer Product Safety CommissionRetrieved 2026-09-14
- Plumbers, Pipefitters, and Steamfitters - median pay, May 2025U.S. Bureau of Labor Statistics, Occupational Outlook HandbookRetrieved 2026-09-14
Sources for the figures and the legal requirements cited on this page.
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