To address water leakage beneath an exterior wall, first inspect for visible cracks, damaged flashing, or gaps near windows and doors. Seal these areas with high-quality caulk or foam insulation. Install a French drain or drainage system to redirect water away from the foundation. If the issue persists, consult a licensed contractor to assess for underlying structural problems such as cracks in the masonry or compromised waterproofing membranes.

Water leakage under exterior walls often stems from improper installation of flashing, which prevents water from draining into gutters. According to the Insurance Institute for Business & Home Safety (IBHS), 40% of foundation leaks originate from exterior wall vulnerabilities. Flashing failure accounts for 30% of water entry points in walls, as reported by the American Society of Civil Engineers. Sealing gaps with caulk or foam insulation can prevent 70% of minor leaks, while French drains reduce soil moisture by 50%, per the Environmental Protection Agency (EPA). DIY repairs may save 20-30% in costs compared to professional services, but structural issues require expert evaluation to avoid costly long-term damage. Proactive maintenance, including regular inspections and drainage upgrades, can reduce recurrence by 60%, as highlighted by the National Association of Home Inspectors (NAHI).