Harris County, TX Hurricane Preparedness: Flood Elevation (2026)
Key Facts
- Minimum rise
- 12 inches above grade or street crown
- Non-residential slab exposure
- 6 inches minimum
- Permit authority
- Harris County Engineer
- Applies to
- Non-Conforming Subdivision lots, unincorporated county
Summary
New homes on non-conforming lots in unincorporated Harris County must set the finished floor at least 12 inches above the highest adjacent grade or street crown.
If the structure is a single family residence the finished floor shall be a minimum of 12 inches above the highest adjacent natural grade when measured 10 feet from the edge of the slab or 12 inches above the crown of the adjacent street which ever results in the highest elevation (an exception may be granted on sloping properties where the crown requirement is not achievable).
Full Breakdown
Harris County's floodplain permit rules set minimum finished-floor heights instead of zoning setbacks, since the county cannot zone. For a single-family residence on a Non-Conforming Subdivision lot, the County Engineer requires the finished floor at least 12 inches above the highest adjacent natural grade (measured 10 feet from the slab edge) or 12 inches above the crown of the adjacent street, whichever is higher; non-residential structures need 6 inches of slab exposure plus the same 12-inch street-crown minimum. Lots partly in the 0.2%-annual-chance (500-year) floodplain must instead hit that flood level. These are Class I permit conditions administered by the County Engineer under Chapter 19; stricter Class II elevation and floodproofing rules apply once a lot falls in the mapped 1%-annual-chance floodplain or floodway.
Violations & Fines
Building without a floodplain development permit, or below the required finished-floor elevation, blocks certificate of occupancy and can trigger stop-work action and fines from the County Engineer's office; it also jeopardizes NFIP flood insurance eligibility for the structure.
Frequently Asked Questions
Does this apply inside Houston?
What if my lot is in the 500-year floodplain?
Sources & Official References
Other rules in Harris County
Texas rules heatmap·Compare Harris County to another location·View the Texas hurricane preparedness overview
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