can a water heater leak intermittently?

my sister came home to her house with the basement floors soaking wet(steady rain outside). The laundry room (no carpets) containing the furnace and gas water heater was all wet and the finished part of the basement (carpets) was wet in a pattern which seemed to center opposite to where the gas water heater is located but no way to tell 100%. We felt the carpets all around the exterior walls and nowhere was it wet anywhere within 5 feet. No leaking copper, no backed up drains, sump pump working fine so my best deduction was the gas water heater. However we dried the floor next to the gas water heater but 6 hours later not a drop has come out.

This happened a few weeks ago to a much smaller extent (when it was not raining) so my question is can a water heater somehow leak and then not leak?


Natural gas when burned gives off twice as much water vapor as it does carbon dioxide. Those are the main byproducts of combustion of natural gas, theoretically the only ones under perfect conditions. If the heater is set to a low temperature and the use of hot water is heavy or prolonged, the cold incoming water can chill the tank resulting in condensation of the water vapor in the flue gases. That could be interpreted as an intermittent leak. The cures might include increasing the temperature of the heater, being more conservative in the use of hot water (shorter showers?), or replacing with a larger heater. This condition would not happen with an electric heater.