Wisconsin Lot Coverage Limits (2026)

Key Facts

Code: Wis. Admin. NR 115
Standard Limit: 15% impervious
With Mitigation: Up to 30%
Zone: 300 ft from OHWM

Full Breakdown

Wis. Admin. Code NR 115.05(1)(e) limits impervious surfaces in shoreland zones to 15 percent of the lot area within 300 feet of the ordinary high water mark, or 30 percent with approved mitigation. 2015 Wisconsin Act 55 prohibited counties from imposing stricter limits. Impervious surfaces include roofs, driveways, sidewalks, and similar features. Mitigation typically involves restored vegetation, rain gardens, or stormwater management practices. Non-shoreland lot coverage rules remain local zoning matters under Wis. Stat. § 62.23.

Violations & Penalties

Exceeding impervious limits without mitigation may require removal of structures, payment of forfeitures, and restoration. Enforcement is through county zoning administrators.

Frequently Asked Questions

What counts as impervious surface in Wisconsin shoreland zones?

Roofs, paved driveways, sidewalks, patios, and any surface that prevents water infiltration. Gravel surfaces with proper underlayment may not count if they allow drainage.

Can I exceed 15% coverage on a Wisconsin shoreland lot?

Yes, up to 30 percent with approved mitigation measures like rain gardens or stormwater controls. Counties enforce mitigation plans under NR 115 standards.

Wisconsin Shoreland Impervious Surface Coverage Limits