Water in the Pan Under a New Water Heater
On this page (6 sections)
The Short Answer: Water in the pan under a brand-new heater is rarely a failed tank. On a new gas heater, the most common source is condensation from the burner while the tank is still full of cold water. Other common sources are the relief valve discharging because of thermal expansion, a drain valve not fully closed, or a fitting that needs attention. Dry everything, then watch where water reappears.
Find where it’s coming from
Wipe the pan, the bottom of the heater, and all visible fittings dry. Then check every 15 to 30 minutes, especially while the heater is heating.
| What you find | Likely source | What it means |
|---|---|---|
| Gas heater: drips from the burner area or bottom, mostly during the first heat-up or after large hot water use | Condensation from combustion gases on the cold tank | Usually normal; should stop once the tank is hot |
| Water in or at the end of the relief valve discharge pipe | Relief valve opening, often from thermal expansion | Check pressure and expansion control |
| Drip from the hose outlet of the drain valve | Drain valve not fully closed or a faulty washer | Minor fix |
| Wet threads or connectors at the top of the heater | Fitting or connector | Installer should tighten or reseal |
| Electric heater: water around an element access cover | Element gasket | Installer; leave power off if water reaches wiring |
| Heat pump water heater: water from a hose near the top | Condensate drain not connected or blocked | Connect or clear the condensate line |
| Water seeping from the jacket with all fittings dry | Tank damage (rare on a new unit) | Shut the heater down; warranty claim |
| Pan wet, heater dry | Something else: AC drain, pipe above, washer | Look around and above |
Condensation on new gas heaters
When a gas water heater is filled with cold water and the burner first fires, water vapor in the combustion gases condenses on the cold tank surfaces and drips onto the burner and into the pan. A. O. Smith’s technical bulletin on condensation (opens in a new tab) explains that this is often mistaken for a leak, and that it should stop once all the water in the tank is heated above about 115°F. It’s most noticeable with new installs, cold incoming water, and large hot water draws.
If water keeps appearing after the tank is fully hot, or keeps putting the pilot or burner out, look for another source. See gas water heater dripping on the burner.
Relief valve discharge from thermal expansion
When water heats, it expands. If your home has a pressure-reducing valve, check valve or backflow preventer, that expansion has nowhere to go and the pressure rises. A new heater may be the first time anyone notices, especially if the old heater’s relief valve was worn or an expansion tank was never installed. A. O. Smith’s bulletin on thermal expansion explains why an expansion tank or other expansion control is needed in a closed system.
Never cap or plug the relief valve or its discharge pipe. It’s a safety device. See relief valve leaking on a new water heater.
What you can check safely
- Dry everything and track where water first appears.
- Make sure the drain valve at the bottom is fully closed. Hand-tighten only.
- Look at the end of the relief valve discharge pipe for water.
- If you have a hose-bib pressure gauge, check static pressure at an outdoor tap, including first thing in the morning after the heater has been heating overnight.
- For a gas heater, note whether the drip happens only while the burner is running and the tank is still heating.
Don’t tighten fittings on the tank, remove covers, or adjust gas or electrical parts.
What the installer will check
The installer will reseat or replace a leaking drain valve, connector or fitting, and check element gaskets on an electric tank. They measure house water pressure and check the expansion tank’s charge, or add expansion control if there isn’t any. They also confirm the relief valve is the correct rating and isn’t damaged. If water is coming from the tank itself, they document it for a warranty replacement.
Frequently Asked Questions
Q: Is condensation in the pan normal on a new gas heater? A: Yes, during the first heat-up and sometimes after heavy use, especially in winter. It should stop once the tank is hot. Steady water when the tank is hot, or water from a fitting or the relief valve, isn’t condensation.
Q: Should I turn off a new heater with water in the pan? A: Not for normal first-firing condensation. Turn it off if water is coming from the tank body, reaching the burner compartment or electrical parts, or increasing. For gas, use the control’s off or vacation setting. For electric, use the breaker.
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.
- A. O. Smith technical bulletin 15: condensation (opens in a new tab)Why combustion condensate can resemble a tank leak; not a diagnosis of another manufacturer’s model.
- A. O. Smith technical bulletin 51: puddles around a heater (opens in a new tab)Common water-leak sources and the distinction between fittings and a failed tank.
- A. O. Smith technical bulletin 45: thermal expansion (opens in a new tab)Background on pressure rise in a closed water system. Pressure testing and repairs are professional work.
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