Site & Civil / Stormwater measure
Impervious surface
Definition
Any hard surface, such as a roof, driveway, patio, or sidewalk, that prevents rainwater from soaking into the ground.
Fig. 242 — Impervious surface: schematic studyNOT TO SCALE
Structural & construction notes
Many cities limit impervious area or require stormwater management above a threshold. Permeable pavers, gravel, and rain gardens can reduce the counted area.
Frequently Asked Questions
An educational reference. Project-specific design requires professional guidance.