Wicomico County, MD Building Setbacks & Zoning: Lot Coverage Limits (2026)
Key Facts
- Base impervious cap
- 15% of gross site area
- Half-acre pre-1985 lot
- Up to 25%, or 31.25% with mitigation
- Quarter-to-one-acre pre-1985 lot
- 15% or 5,445 sq ft, whichever greater
- Post-1985 subdivision lot (up to 1 ac)
- 25% per lot, 15% subdivision-wide
- Expansion condition
- On-site water-quality mitigation required
- Fine
- Up to $10,000 per day (§ 125-48)
Summary
In the Chesapeake Bay Critical Area of unincorporated Wicomico County, § 125-20H caps man-made impervious surface at 15% of the gross site area, with higher grandfathered limits for small parcels that existed before December 1, 1985: up to 25% for a half-acre lot, or 31.25% under added mitigation conditions.
H. Except as otherwise provided in this subsection for stormwater runoff, man-made impervious surfaces are limited to 15% of the gross site area except as follows: ... (1) If a parcel or lot 1/2 acre or less in size existed on or before December 1, 1985, then man-made impervious surfaces are limited to 25% of the parcel or lot. Impervious surfaces on such parcels or lots may cover up to 31.25% of the parcel or lot or 500 square feet more than 25% of the parcel or lot, whichever is greater, provided the conditions as stated in Subsection H(4) below are met. (2) If a parcel or lot greater than 1/4 acre and less than one acre in size existed on or before December 1, 1985, then man-made impervious surfaces associated with that development are limited to 15% of the parcel or lot or 5,445 square feet, whichever is greater, provided the conditions as stated below are met. (3) If an individual lot one acre or less in size is part of a subdivision approved after December 1, 1985, then man-made impervious surfaces of the lot may not exceed 25% of the lot. However, the total of the impervious surfaces over the entire subdivision may not exceed 15%.
Full Breakdown
Section 125-20H, part of the county's Critical Area Resource Protection chapter, sets the baseline lot-coverage rule for limited development and resource conservation areas: except as separately provided for stormwater runoff, man-made impervious surfaces are capped at 15% of the gross site area. 25% of the lot, or 500 square feet more than 25%, whichever is greater, once the water-quality mitigation conditions in § 125-20H(4) are met. A parcel between a quarter-acre and one acre that predates December 1, 1985 is capped instead at 15% of the lot or 5,445 square feet, whichever is greater.
For an individual lot of one acre or less created by a subdivision approved after December 1, 1985, impervious coverage on that single lot may reach 25%, but the impervious total across the entire subdivision still may not exceed 15%. Expanding coverage past the base 25% or 15% thresholds requires the applicant to show that water-quality impacts from the new impervious area have been minimized through site design, and to perform on-site mitigation to offset any remaining water-quality impact, before the county allows the additional coverage.
Violations & Fines
Exceeding the § 125-20H impervious limit inside the Critical Area is a civil infraction under § 125-48B, carrying a fine of up to $10,000 per violation, far higher than the general zoning penalty, with each day of continued excess coverage treated as a separate offense. The Planning Director must act on every identified violation, and payment of civil penalties is a precondition to any further permit or approval.
Frequently Asked Questions
How much of my lot can I pave or build over in the Wicomico County Critical Area?
My half-acre lot predates 1985. What's my impervious limit?
Does the impervious limit apply per lot or across the whole subdivision?
What's the penalty for exceeding the impervious surface limit?
Sources & Official References
Other rules in Wicomico County
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