Plaza systems are constructed with various types of concrete, steel, pavers, bricks, waterproofing items and architectural elements. Plazas mainly serves as a gathering area and are usually provided over occupied spaces when constructed in parking facilities or other commercial structures. A strong understanding of plaza design and environmental impact of the plaza performance is vital to completing assessment and rehabilitation of plazas. The main issue relating to plaza systems is leaks into the occupied space below. Material selection (pavers, concrete, waterproofing membrane), types of drains (surface drain verses bi-level drains) and drain locations are two of the many elements that has to be carefully studies when considering design or rehabilitation of plaza systems.