To address water seepage on building exterior walls, first inspect for sources like faulty flashing, cracks, or poor drainage. Apply waterproof sealants or coatings to damaged areas and install drainage systems such as gutters, downspouts, and French drains. For severe cases, consider replacing compromised materials or hiring professionals for waterproofing membranes. Regular maintenance, including grading and vegetation management, helps divert water away from the foundation.

Water seepage occurs when water infiltrates walls through cracks, gaps, or inadequate drainage, leading to structural damage, mold growth, and reduced energy efficiency. According to the U.S. Environmental Protection Agency (EPA), addressing moisture issues can prevent up to 30% of heating and cooling costs. The Insurance Institute for Business & Home Safety (IBHS) reports that water damage accounts for 14% of property insurance claims, with exterior wall failures costing an average of $5,000–$10,000 to repair. Waterproofing measures like sealants and drainage systems create a barrier that blocks 90% of water penetration, as shown in a 2021 study by the American Society of Civil Engineers. Proper grading reduces ground water near walls by 60%, while gutters and downspouts direct 5,000–10,000 gallons of rainwater annually away from foundations. Neglecting these steps can escalate costs, as mold remediation alone averages $3–$7 per square foot. Proactive maintenance ensures long-term structural integrity and compliance with building codes, which mandate water-resistant materials in vulnerable areas.