Allen, TX Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Residential freeboard
- 24 inches above BFE
- Nonresidential
- 18 inches above BFE
- Permit
- Development permit required
- Enforcer
- Director of Engineering
- Penalty
- Up to $2,000 per violation
Summary
In Allen's FEMA special flood hazard areas, new and substantially improved homes must have their lowest floor elevated 24 inches above the base flood elevation; nonresidential buildings get 18 inches. The Director of Engineering enforces it through a required development permit.
Residential construction (at grade). New construction and substantial improvement of any residential structure shall have the lowest adjacent grade or lowest floor (including the basement), which ever value is lower to 24 inches above the base flood elevation... Nonresidential construction. New construction and substantial improvements of any commercial, industrial or other nonresidential structure shall either have the lowest adjacent grade or lowest floor (including basement), which ever value is lower elevated to 18 inches above the base flood elevation...
Full Breakdown
Allen sets a strict freeboard standard in Land Development Code Article V. Under Sec. 5.01.7.2, at-grade residential new construction and substantial improvements must have the lowest floor (or lowest adjacent grade, whichever is lower) raised to 24 inches above the base flood elevation, certified by an engineer, architect, or surveyor. Elevated homes must lift the lowest horizontal structural member to the same 24 inches, and manufactured homes match it. Nonresidential buildings must reach 18 inches above BFE or be dry-floodproofed. The Director of Engineering serves as floodplain administrator, no structure may be built in the special flood hazard area without a development permit, and development may cause no rise above one foot in the base flood. The mapped hazard follows the Collin County FIS dated June 7, 2017.
Violations & Fines
Building or altering land in the flood hazard area without compliance is a misdemeanor, punishable on conviction by a fine up to $2,000 per violation plus all case costs; missing elevation certification is presumed a violation.
Frequently Asked Questions
How high must a new Allen home be above the flood level?
Do commercial buildings follow the same rule?
Who administers Allen's floodplain rules?
Sources & Official References
Other rules in Allen
Texas rules heatmap·Compare Allen to another location·View the Texas environmental rules overview
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Flood Elevation Requirements in Nearby Cities
How other cities in Collin County handle flood elevation requirements.