Brand New Water Heater Making Popping Noises
On this page (6 sections)
The Short Answer: Light popping or ticking from a heater that’s only days old is usually harmless. Air may still be leaving the tank and pipes, new pipes tick as they expand, or condensation sizzles on a gas burner while the tank heats from cold. These sounds fade within days. A loud bang or whoosh when a gas burner lights is different. That’s delayed ignition and needs a technician.
Sediment is unlikely in a new tank
Popping in an older tank is usually water trapped under a layer of scale on the bottom. A new tank hasn’t had time to build that up, so look for other causes first. If you have very hard water and the noise starts after many months, sediment becomes the likely cause. See water heater sounds like rocks.
Match the sound
| What you hear | When | Likely cause | Action |
|---|---|---|---|
| Sizzling or hissing at the burner of a gas tank | While heating a cold tank | Condensation dripping onto the burner | Normal at first. It should stop once the tank is warm |
| Ticking or light popping along the pipes | During heating, or when hot water starts and stops | Pipes expanding and contracting against straps or framing | Usually harmless. A plumber can add clearance or isolators |
| Spitting at taps, cloudy water that clears in a glass | First days after installation | Air still in the system | Run each hot tap until the flow is smooth |
| One loud bang or whoosh at the moment the burner lights | At ignition | Delayed ignition | Turn the heater off and call a technician |
| Banging when a tap is shut off quickly | When flow stops | Water hammer in the pipes | Plumber can add arrestors |
| Clicking from the relief valve, or water at its discharge pipe | During heating | Pressure building from thermal expansion | Have the expansion control and water pressure checked |
Condensation on a new gas tank
When a gas tank heats from cold, combustion produces water vapor that condenses on the cold tank surfaces and drips onto the burner. This makes sizzling or popping sounds and can leave a little water under the heater. A. O. Smith’s technical bulletin on condensation describes the effect and explains that it decreases as the tank warms up. If water keeps appearing once the tank is fully hot, have it checked as a possible leak. See new water heater has water in the pan.
Pressure and the relief valve
Many homes have a check valve or pressure-reducing valve that stops expanding hot water from flowing back into the supply. Without a working expansion tank, the pressure rises each time the heater runs. You may hear the relief valve, or see it drip. Never cap it. The installer should check the house water pressure and expansion control. See pressure relief valve leaking on a new water heater.
Electric tanks
An electric tank should run almost silently, apart from some ticking in the pipes. If you hear sizzling or crackling inside an electric tank that’s only days old, the element may have been damaged during startup. This can happen if it was powered before the tank was full. Ask the installer to check it. See water heater turned on without water.
Frequently Asked Questions
Q: Should I flush a new water heater to stop popping? A: There’s nothing to flush out of a tank that’s days old. Flushing won’t stop air, pipe or condensation noises.
Q: How long should new-heater noises last? A: Air and condensation sounds usually fade within the first few days of normal use. Pipe ticking can continue but should stay quiet and steady. Any bang at ignition, or a noise that gets louder, needs a visit from the installer.
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 45: thermal expansion (opens in a new tab)Background on pressure rise in a closed water system. Pressure testing and repairs are professional work.
- 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