UNKNOWN WATER LEAKAGE CAUSING WATER TO FLOW ONTO 3RD., 2ND, 1ST AND LOWER GROUND FLOORS

For the past 1 month, an unknown water leakage from 4th. Floor has caused water to flow onto the floors besides our lift lobbies on 3rd.,2nd., 1st and lower ground floors. This water leakage began about 1.5 months ago.
The water is seeping between the common wall that separate Block I and our Block J.
2 weeks ago, our JMB engaged a contractor to hack a hole in the common wall of the 3rd. Floor . We noticed water is dripping from the 4th.floor of Block I. There are toilets located on their 4th. Floor offices.
Action is being taken to trace the source of the water leak before it causes further damage to our building lobbies.