Impervious surface coverage limits explained simply
By My Yard Editorial Team · 7/28/2026
The Quick Answer
Most residential zones cap impervious coverage at 25–40% of lot area. Driveways, patios, roofs, and sheds all count — and exceeding the cap can block your permit or force a stormwater plan.
The Witty Breakdown
People discover this when adding a patio to a house that already has a big driveway and a detached garage. The math is already close.
Permeable pavers sometimes count partially, or not at all, depending on your municipality. Ask specifically.
Step-by-Step Fix
- 1
Get your lot square footage from the deed or tax record.
- 2
Add up every hard surface: roof footprint, driveway, walks, patios, sheds.
- 3
Call zoning to ask how permeable surfaces are credited locally.
- 4
If you're near the cap, plan gravel or permeable options for the new work.
Pro-Tip / Do Not Do This
Don't pour first and ask later. Removing an over-cap patio is the most expensive way to learn a zoning rule.
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