---
title: "Impervious Cover: Definition & Why It Matters for Contractors — PermitVector"
source: https://permitvector.com/glossary/impervious-cover
description: "Any surface that prevents rainwater from percolating into the ground, such as rooftops, driveways, and paved areas; regulated by zoning and watershed rules."
---

# Impervious Cover: Definition & Why It Matters for Contractors

> Any surface that prevents rainwater from percolating into the ground, such as rooftops, driveways, and paved areas; regulated by zoning and watershed rules.

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Permit Glossary

# Impervious Cover

Also known as: impervious surface, hard cover

Any surface that prevents rainwater from percolating into the ground, such as rooftops, driveways, and paved areas; regulated by zoning and watershed rules.

Impervious cover refers to surfaces — rooftops, concrete driveways, asphalt parking lots, compacted gravel — that prevent stormwater from infiltrating the soil. Local governments, especially in water-sensitive areas of Texas such as the Edwards Aquifer recharge zone (Austin, San Antonio), set maximum impervious cover limits as a percentage of the total lot area. Exceeding the limit requires a variance or the use of engineered mitigation (permeable pavers, detention basins). Impervious cover calculations are reviewed during plan check for additions, new construction, and hardscape projects.

## Why it matters for contractors

Projects that push against a parcel's impervious cover limit may require civil engineering, grading, or drainage work as a condition of permit approval — creating a secondary lead for those specialty contractors.

## Related terms

[Zoning](/glossary/zoning) [Setback](/glossary/setback) [Plan Review](/glossary/plan-review) [Parcel](/glossary/parcel) [Variance](/glossary/variance)

[← All permit & construction terms](/glossary)

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_Source: https://permitvector.com/glossary/impervious-cover · PermitVector — daily Texas building-permit intelligence._