Fond du Lac County, WI Building Setbacks & Zoning: Lot Coverage Limits (2026)
Key Facts
- Base impervious cap
- 15% within 300 ft of OHWM
- Highly developed shoreline, residential
- up to 40%
- Highly developed shoreline, commercial
- up to 60%
- Mitigation-permit ceiling, residential
- up to 30% (or 40% if highly developed)
- Measurement band
- within 300 ft of OHWM
- Penalty range
- $50-$500 per offense per day
Summary
Within shoreland areas of unincorporated Fond du Lac County, impervious surface on the portion of a lot within 300 feet of the ordinary high-water mark is capped at 15 percent under Code Sec. 44-283, rising as high as 40-60 percent on mapped highly developed shorelines or with a mitigation plan.
(NR 115.05(1)(e)2.) Except as allowed in sections section 44-284 through 44-286 allow up to 15 percent impervious surface on the portion of a lot or parcel that is within 300 feet of the ordinary high-water mark.
Full Breakdown
Fond du Lac County Code Sec. 44-283 sets the general impervious surface standard for shoreland areas: except as allowed under Secs. 44-284 through 44-286, a property is limited to 15 percent impervious surface on the portion of the lot or parcel within 300 feet of the ordinary high-water mark. Sec. 44-282 defines how that percentage is calculated, dividing the existing and proposed impervious surface area within the 300-foot band by the total area of that portion of the lot, then multiplying by 100; treated surfaces excluded under Sec.
44-286, such as those draining to stormwater ponds, rain gardens or bio-swales, do not count toward the total. Sec. 44-284 raises the cap on mapped 'highly developed shorelines,' areas identified as urbanized in the 2010 U.S. Census or already in commercial, industrial or business use as of January 31, 2013: those areas allow up to 40 percent impervious surface for residential use and up to 60 percent for commercial, industrial or business use. Sec. 44-285 allows a property to exceed the base 15 percent standard, up to 30 percent for residential or 40 percent for commercial/industrial/business use, and to exceed the highly-developed-shoreline standard up to 40 percent residential or 60 percent commercial, provided the property owner obtains a permit conditioned on a mitigation plan meeting Sec.
44-331. This impervious surface standard governs only the portion of a lot or parcel within 300 feet of the ordinary high-water mark in shoreland areas of unincorporated Fond du Lac County; it does not set a general lot-coverage cap for land elsewhere in the unincorporated county.
Violations & Fines
Exceeding the applicable impervious surface percentage without an approved mitigation permit is a violation of Chapter 44, enforced under Sec. 42-431 (Article XVI). The zoning administrator refers violations to the corporation counsel for prosecution, and a violator faces a forfeiture of not less than $50.00 nor more than $500.00 per offense, with each day of continued violation treated as a separate offense, plus taxable costs of the action.
Frequently Asked Questions
What is the impervious surface limit in shoreland Fond du Lac County?
Can the impervious limit be higher on developed shorelines?
How do I exceed the base 15 percent limit?
What surfaces don't count toward the impervious total?
Sources & Official References
Other rules in Fond du Lac County
Compare Fond du Lac County to another location·View the Wisconsin building setbacks & zoning overview
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