The vast majority of water vapor comes from the products of combustion. If you’re getting that much water from catalyzed unburned hydrocarbons and oxides of nitrogen in the exhaust then there’s something wrong with your engine.Water coming out of the exhaust simply means your catalytic converter is doing its job. When you burn gasoline, you get CO2 and H2O as combustion products in an ideal environment. Since engines rarely if ever manage an ideal environment we have extra combustion products, CO and NOx being the primary offenders along with bits of fuel that didn't burn. Your catalytic converter's job is to convert these unwanted species into CO2 and H2O. The water condenses against cool parts of the exhaust system and eventually makes it out the end of the pipe. It's not unusual or bad. When you start driving down the road the increased exhaust flow will heat up the pipes and evaporate any liquid water and send it out of the system.
It's normal. Especially in cooler weather under extended idling where you have chilled pipes until you get going down the road.