Gas Water Heater Not Getting Gas: What to Check
On this page (5 sections)
The Short Answer: First check whether other gas appliances work. If none do, the problem is the gas supply: an empty propane tank, a closed meter, or a utility shutoff. If only the water heater is affected, check that its gas shutoff valve is open and that the control is set according to the lighting label. Beyond that, a technician must check the gas control and supply pressure. Never loosen a fitting to check for gas.
Is it the house or just the heater?
| What you find | Most likely cause | Who to call |
|---|---|---|
| Stove, furnace, and other gas appliances also dead | Supply problem: utility shutoff, meter valve closed, or empty propane tank | Gas utility or propane supplier |
| Propane tank gauge reads near empty | Out of fuel, or below the level the regulator can deliver | Propane supplier; they will leak-check and relight after a run-out |
| Other appliances work, heater’s gas valve handle is across the pipe | Heater’s shutoff valve is closed | Turn it parallel to the pipe, then follow the lighting label |
| Other appliances work, valve open, pilot will not light | Pilot, igniter, or gas control | See water heater burner not lighting |
| Pilot lights but the main burner will not come on | Control, thermostat setting, or a safety lockout | See pilot lit but burners won’t ignite |
| Heater and furnace both stopped at the same time | Shared supply, vent, or power problem | See water heater and furnace not working |
What you can check safely
- Test another gas appliance, such as the stove. If nothing lights, contact the utility or propane supplier.
- Look at the propane gauge if you use LP. Many suppliers require a leak check before relighting after a run-out, which is a safety step, not a formality.
- Check the heater’s gas shutoff valve. The handle in line with the pipe means open; across the pipe means closed.
- Check the control knob is not in OFF or VACATION, and then follow the lighting instructions on the heater’s label once.
- On power-vent and tankless models, confirm the unit has electrical power. Without power, the gas valve will not open even though gas is present.
If the pilot will not light after one attempt following the label, stop. Repeated attempts are not a diagnostic step.
What the technician will check
A gas technician measures supply pressure at the heater’s test port while other gas appliances run, which shows whether the line is undersized or the regulator is failing. They check the gas control for a failed internal valve, inspect the pilot tube and orifice for blockage, and look at the sediment trap and connector. After a new meter, new piping, or a propane run-out, they purge air from the line under controlled conditions. That work involves opening gas piping and is not a homeowner task; see how to purge air from a gas line for why.
Repair or replace
Supply problems are fixed by the utility or supplier. A failed gas control or a blocked pilot is a part repair. Only if the heater has other major problems, such as a leaking tank, does replacement enter the picture.
Frequently Asked Questions
Q: Can air in the gas line stop the heater from working? A: Yes, after a meter change, new piping, or a propane tank running empty. A heater that worked yesterday with nothing changed is more likely to have a closed valve, a supply issue, or a failed part. Purging is done by a technician.
Q: My propane tank was refilled but the heater still won’t light. Why? A: After a run-out, air may be in the line and the pilot may need relighting, and many suppliers perform a leak check before restoring service. If it still will not light after the supplier’s check and one attempt following the label, have the heater serviced.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- PG&E: recognizing and responding to a gas leak (opens in a new tab)Emergency actions for suspected fuel-gas leaks.
Editorial standards and corrections · Prepare a useful service request