Wisconsin Statewide Rule

Wisconsin Shoreland Impervious Surface Coverage Limits

Heavy RestrictionsApplies statewide across Wisconsin (2026)

Key Facts

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

Last verified: September 5, 2026Source: Wisconsin State Legislature

Summary

Wisconsin Administrative Code NR 115 sets uniform impervious surface coverage limits for shoreland properties statewide. Counties must adopt these standards, typically capping coverage at 15 percent, with mitigation allowing up to 30 percent in certain circumstances.

2. 'General standard.' Except as allowed in subds. 2m. to 4., a county may allow up to 15% impervious surface as calculated under subd. 1m on a lot or parcel described in subd. 1. NR 115.05(1)(e)2m.2m. 'Standard for highly developed shorelines.' At its discretion, a county may adopt an ordinance for highly developed shorelines that allows impervious surface as calculated under subd. 1m on lots or parcels described in subd. 1 as follows: up to 30% for residential land uses or up to 40% for commercial, industrial or business land uses. NR 115.05(1)(e)2m.a.a.

Source: Wisconsin State LegislatureView official code

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.

Sources

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