A weep hole is a small, intentional opening integrated into various architectural assemblies—most commonly masonry veneer walls, retaining walls, and window frames—to facilitate the drainage of accumulated water and provide essential ventilation. By allowing moisture that has penetrated the exterior skin or formed through condensation to escape the internal cavity, weep holes prevent structural damage such as dry rot, mold growth, and corrosion of wall ties. In retaining walls, they serve a critical structural role by relieving hydrostatic pressure from the soil, while in window systems, they prevent water from pooling on the sill. Often appearing as unfilled vertical mortar joints or small tubes, these apertures are vital for maintaining the long-term integrity and performance of a building's envelope.