Hi Mohammed,

It's quite normal for water to come out of an exhaust when a car starts up from cold. Water vapour can easily get trapped in the exhaust system when you stop the car and this condenses to liquid when it cools down. Symptoms of a head gasket gone would include overheating, steam in the exhaust under hard acceleration and bubbles in the coolant when the engine is running.

If you have any doubts you should bring the car to a qualified mechanic to check over.

Hope that helps.