What is the likely cause of water damage in a building during heavy rainfall?

Water damage during heavy rainfall is primarily linked to poor drainage or roofing issues that can lead to leaks. When rainfall is excessive, it can overwhelm existing drainage systems or reveal vulnerabilities in roof structures. If gutters are clogged or improperly installed, rainwater may overflow, seeping into the building's structure. Similarly, if roofing materials are damaged or worn, they may allow water to penetrate, causing interior damage such as mold growth, rot, or deterioration of building materials.

In contrast, while overwatering plants can contribute to localized flooding, it is not typically a primary source of water damage during significant rainfall. Cracks in the foundation might allow water ingress but are often secondary concerns compared to direct rainfall effects on roofs and drainage systems during heavy weather. Faulty plumbing in upper floors can also result in water issues, but this is separate from the widespread effects of heavy rain and does not directly relate to external weather conditions.