An air inlet system for gas water heaters that prevents or delays the ignition of fumes from flammable liquids accidentally spilled on the floor. The air inlet is above the quickly combustible fumes from spilled liquids, allowing time for personal escape or other response. Two concentric air baffles are placed around the tank of the water heater, and are sealed against the floor. They are spaced from each other and from the tank, forming two concentric air chambers around the tank which are open at the top. The inner air baffle is taller than the outer baffle, and has holes or gaps around its lower end for air passage. When the burner is operating, combustion inlet air enters the top of the outer air chamber, travels downward, passes through the holes in the inner baffle, and under the tank to the burner. When the burner is off, the inner air chamber is warmed by the tank, causing convection between the outer and inner chambers that constantly refreshes the air in the chambers, preventing inefficient burning, CO production, or flame-out of the pilot or burner from oxygen depletion.