Grand Prairie, TX Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Enforcing official
- City Floodplain Administrator
- Residential lowest-floor elevation
- BFE +1 ft, or FIRM BFE +2 ft
- Nonresidential floodproofing option
- BFE plus two feet
- Certification required
- Registered engineer or surveyor
- Permit required
- Floodplain Development Permit before building
- Fill setback
- 15 feet beyond structure limits
- Penalty basis
- Fined under Code § 1-8, per day
Summary
Any new home or business built in a mapped Grand Prairie floodplain must set its lowest floor at least one foot above the fully-developed base flood elevation, or two feet above FEMA's mapped 100-year BFE, whichever is higher, under UDC § 15.18.1. A registered Texas engineer or surveyor certifies the elevation to the City's Floodplain Administrator before the project closes out.
15.18.1 In all SFHAs where base flood elevations data has been provided as set forth in this Article, the following provisions are required: A. Residential Construction - New construction and substantial improvements of any residential structure shall have the lowest floor elevation (including basement) be the greater of one foot above the base flood elevation (BFE) for fully developed conditions in the watershed or two feet above the FEMA FIRM 100-year (1% annual chance) BFE that utilizes existing land use conditions. A registered surveyor or registered professional engineer shall submit a certification to the Floodplain Administrator that the standard of this subsection as proposed in Section 15.15.2 "Floodplain Development Permit (FDP) Procedures" of this Article has been followed.
Full Breakdown
Grand Prairie's Unified Development Code, Article 15, sets the flood-elevation standard for anything built in a Special Flood Hazard Area (SFHA) once base flood elevation (BFE) data exists. 1(A), new and substantially improved residential structures must have their lowest floor, including any basement, at the greater of one foot above the BFE calculated for a fully developed watershed, or two feet above the FEMA FIRM 100-year BFE based on current land use; parking areas and open storage only need one foot above the BFE. 2.
1(B), but may floodproof instead: the design must be sealed by a licensed Texas engineer, resist hydrostatic and hydrodynamic loads, and protect the structure to the BFE plus two feet, with a record of the certified elevation kept by the Administrator. Fill placed under a structure in the floodplain but outside the floodway must extend at least 15 feet beyond the building's limits, and any septic system must sit at the same lowest floor elevation as the structure. 1), with fees set by UDC Article 22. 1). 2). 1).
Violations & Fines
Building in a Special Flood Hazard Area without a Floodplain Development Permit is a violation under § 15.24.1(A); the violator must restore the property to its prior condition or complete the permitting process (§ 15.24.2). Conviction brings a fine under Code of Ordinances § 1-8, with each day of continued noncompliance a separate offense (§ 15.26.1). Sellers who skip the written floodplain disclosure before closing face the same penalty (§§ 15.12.1-15.12.2).
Frequently Asked Questions
How high above flood level must I build in Grand Prairie's floodplain?
Who has to certify my home's flood elevation?
Can a commercial building floodproof instead of raising the floor?
What happens if I build in the floodplain without a permit?
Sources & Official References
Other rules in Grand Prairie
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Flood Elevation Requirements in Nearby Cities
How other cities in Dallas County handle flood elevation requirements.