Answer:
(1) Longitudinal leakage (water leaking from the upper floor down to the lower floor):
(1) Leaks from the lower floor caused by cracks in the bathroom floor or defects in the floor structure.
(2) Water leakage from the ground floor caused by poor waterproofing around the drainage pipes.
(3) Water leakage from the lower floor caused by water accumulating at the bottom of the bathtub.
(4) Water leakage from the walls or floor of the bathroom due to damaged pipes in the upper floors or leaking roofs.
(ii) Lateral leakage (water leaking from the bathroom into the next room or seepage from the bathroom):
(1) Water seepage or mold formation in the neighboring room due to poor waterproofing of the bathroom wall.
(2) Water seepage and mold growth in the neighboring room caused by damaged water pipes in the bathroom wall or poor waterproofing on the pipes.
(3) The floor of the adjacent room has water seepage or mold on the wall below 30cm due to poor waterproofing at the junction between the bathroom floor and the wall.
(4) The phenomenon of dampness on the outdoor floor caused by poor waterproofing of the bathroom door threshold.