Montgomery County, MD Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Required freeboard
- 1 ft above 100-yr flood elevation
- Basements
- Prohibited in the floodplain
- Electrical panels
- 3 ft above flood elevation
- Permit required
- Floodplain District Permit from DPS
- Max penalty
- $1,000 fine / 6 months jail
Summary
New and substantially improved structures in Montgomery County's Floodplain District must set the lowest floor at least one foot above the 100-year flood elevation, and basements are prohibited outright.
Developments when approved, must have the elevation of the lowest floor, as defined in the Code, of all new or substantially improved structures at or above one (1) foot above the elevation of the One Hundred (100) Year Flood. Basements, as defined in the Code, are prohibited in the One Hundred
(100) Year Floodplain.
7. Design, Anchoring, and Materials - All construction when approved, including substantial improvements, must be:
a. Designed (or modified) and adequately anchored to prevent flotation, collapse, or lateral movement of the structure;
b. Constructed and placed on the lot so as to offer the minimum obstruction to the flow and height of the flood water;
c. Constructed with materials and utility equipment resistant to flood damage; and
d. Constructed by methods and practices that minimize flood damage.
8. Landscape Design
a. Adequate ground cover must be provided for soil stabilization within the Floodplain District.
b. Design of land contours and choice of plant materials must direct surface runoff away from structures and must not increase surface runoff onto neighboring properties.
9. Electrical Systems
a. All electric water heaters, electric furnaces, generators, heat pumps, air conditioners, and other permanent electrical installations must be located one (1) foot or higher above the elevation of the one Hundred (100) Year Flood.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-90: Montgomery County Code contains legislation effective through May 7, 2026 | Zoning Updated Effective: April 13, 2026 | COMCOR Regulations effective as of July 1, 2026).
Full Breakdown
Montgomery County's floodplain regulations require the lowest floor of every new or substantially improved structure in the Floodplain District to sit at or above one foot of freeboard over the 100-year (base) flood elevation shown on the Official Floodplain Map. Basements, as defined in the Code, are prohibited in the One Hundred Year Floodplain. Permanent electrical and mechanical installations must also clear the base flood elevation by at least one foot (electrical distribution panels need three feet). The Department of Permitting Services enforces these standards through the Floodplain District Permit process, requiring an elevation certificate from a Maryland-licensed engineer or surveyor documenting the as-built lowest-floor elevation before occupancy.
Violations & Fines
Any Chapter 19 floodplain violation is a Class A offense: up to a $1,000 criminal fine and 6 months in jail, or a $500 civil fine for a first offense ($750 for a repeat); each day the violation continues counts as a separate offense.
Frequently Asked Questions
Does Montgomery County require freeboard above base flood elevation?
Can I build a basement in the Montgomery County floodplain?
Sources & Official References
Other rules in Montgomery County
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