Close the main stopcork at the meter. drain out the water from tap. Than see got anymore leaking. Beginning still got some leaking as the pipe inside still got water. Need longer time to observe. This can tell is your pipe got leaking or not.

Another is, ask the plumber test the pressure of the piping.

Ask the management for the piping plan. See where the pipe run inside your house. Once determine is your own pipe leaking, you can trace the nearest pipe from the plan.