Calvert County, MD Environmental Rules: Flood Zones (2026)

Applications for a floodplain permit must include the applicant's and contractor's contact information, a legal description of the site, the proposed use, and estimated cost of the work, plus a scaled site plan showing setbacks, elevation contours in mean sea level, and the one-hundred-year flood boundary (§ 46-7). The local permitting official, the Calvert County Department of Planning and Zoning working with the Department of Public Works, first pinpoints which Floodplain Zone applies (nontidal, tidal, or the V Zone coastal high-hazard area) using the current Flood Insurance Rate Map and Flood Insurance Study prepared by FEMA, or by elevation survey where no detailed data exists (§§ 46-13 to 46-15).

Work must start within 180 days of permit issuance and finish within 18 months unless the official grants a written extension, and no changes to approved plans are allowed without written approval (§ 46-9). For a subdivision in the nontidal floodplain, the applicant must also show that every lot has a buildable site outside the one-hundred-year floodplain, consistent with Zoning Chapter 155, § 155-4-4C(4), and new subdivisions may not create flood-prone building lots regardless of size or number of lots (§§ 46-8, 46-23). Anyone altering a watercourse needs a variance and must notify FEMA and the Maryland Water Resources Administration, and any nontidal floodplain project with a drainage area over 400 acres needs a state waterway construction permit before the county will issue its own (§ 46-17).

A federal or state permit does not exempt a project from county review, and the county keeps a permanent record of every floodplain permit for FEMA's periodic compliance reviews (§ 46-9C).