Addressing toilet water seepage problem requires identifying whether it's from floor leakage, wall seepage, or plumbing failures. Common in older flats: deteriorated PU/bitumen waterproofing layer fails, allowing water to travel through porous RCC to lower levels or neighbouring units. Visible effects: ceiling dampness in the flat below, efflorescence on bathroom walls, and foul odour... https://shakuraconstruction.sg/toilet-water-seepage-problem/