Permeable pavement (pavers, pervious concrete, porous asphalt): infiltrates ≥ 80% of runoff at driveways + walkways
EPA Stormwater — Permeable pavementDescription
Permeable pavement allows stormwater to pass through the surface into a gravel reservoir below, where it infiltrates into the soil instead of running off. Typical residential use: driveways, walkways, patios. Three main types: permeable pavers (pavers with gaps filled with permeable aggregate); pervious concrete (open-cell concrete); porous asphalt. Reservoir typically 12-24 in of clean ¾-1.5 in stone above well-drained subgrade. Maintenance: periodic vacuum/sweep to prevent clogging.
Why this exists
Replacing a 2-car driveway with permeable pavement eliminates ~400 sqft of impervious area — a meaningful contribution to lot-level stormwater management. Architects + landscape designers should specify permeable pavement at driveways + walkways where soils + water-table conditions permit.
Categories
Source
Solver enforcement
Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.
Related directives
- Exterior ramps: maximum slope 1:12, minimum 36 inch clear width · HUD FHA Design Manual Chapter Two §2.7
- Build to the latest natural-hazard-resistant code edition · FEMA P-2325 §Building Codes Basics
- Coastal-pile foundations should embed deeply to resist erosion + uplift · FEMA P-2325 §Florida Building Code / Sand Palace lessons
- Lowest floor at or above Base Flood Elevation in Special Flood Hazard Areas · FEMA P-2325 §Flood Hazard Provisions
- In WUI zones, protect openings from wind-blown embers · FEMA P-2325 §Wildland-Urban Interface (WUI)
Last reviewed 2026-05-15.