Gas Water Heater Not Working After Rain
On this page (6 sections)
The Short Answer: When a gas tank quits after heavy rain, the water usually came down the vent: a missing or damaged rain cap, a separated joint, or wind-driven rain into a sidewall termination. It can put out the pilot, wet the burner, or trip a power-vent pressure switch. Check the vent, but don’t relight a heater with water in the burner area.
How rain gets in
- Atmospheric (natural-draft) tanks vent through a metal pipe up through the roof. If the cap at the top is missing, bent, or crushed by a fallen branch, rain drops straight down the flue onto the burner.
- Power-vent tanks vent sideways through a wall. Driving rain, a downspout spilling near the termination, or a low termination can push water into the vent, where it collects and blocks the pressure switch.
- Outdoor or carport heaters in a cabinet or enclosure can get wet if a door or panel is missing.
- Crawl-space heaters can sit in standing water after storms; see problems with a water heater in a crawl space.
Signs it was the rain
| What you notice | Likely cause |
|---|---|
| Pilot out only after storms, relights fine once dry | Rain down an uncapped or damaged vent |
| Rust streaks or water marks on the draft hood or top of the heater | Water running down the vent |
| Water dripping from vent joints inside | Rain or condensation in the vent; see water heater vent pipe leaking |
| Power-vent shows a pressure-switch or airflow code after storms | Water in the vent or blocked termination |
| Water around the base and no rain-related signs | Probably a leak, not rain |
What you can check safely
- Look at the vent from the ground. Is the roof cap there and upright? For a sidewall vent, is the termination clear and not filled with water or debris?
- Look at the vent pipe indoors for separated joints, rust, or water trails.
- Look through the sight glass for water in the burner area. If you see water, rust flakes, or wet soot, leave the heater off.
- If the burner area is dry, relight once following the label. If it lights and stays lit, watch it during the next heavy rain.
- For a power-vent model, check that the GFCI or outlet it plugs into didn’t trip, and restart it once.
Don’t pour or spray water into the vent to “flush” it, and don’t take the vent apart.
What the technician will check
A technician inspects the cap and vent run, checks for exhaust spillage at the draft hood once the heater is running again, and dries or cleans the burner, pilot, and flame arrestor if water reached them. On power-vent models they drain water from the vent and pressure-switch tubing and confirm the vent slopes correctly. If water reached the gas control, see gas water heater got wet and pilot won’t light.
Repair or replace
Replacing a rain cap or resealing a vent joint is a minor repair. Drying and cleaning the burner is a service call. Parts that stayed wet long enough to corrode may need replacing.
Frequently Asked Questions
Q: Why does my water heater only go out when it’s windy and rainy? A: Wind can push air and rain down an uncapped or short vent, which can put the pilot out. A proper cap and vent height usually solve it; a technician can confirm the vent meets the heater’s instructions.
Q: My tankless unit stops in the rain. Is it the same problem? A: Similar cause, different equipment. See tankless water heater not working after rain.
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.
- CPSC: carbon monoxide fact sheet (opens in a new tab)Carbon monoxide hazards and emergency response.
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