The unprecedented flooding damage of Hurricane Harvey spurred jurisdictional authorities to get to work reviewing their floodplain regulations and the City of Houston is the next to release their latest changes, following Harris County. The City is keeping their word on raising the regulatory floodplain from the 100-year to the 500-year floodplain elevation and, in some areas, could reflect a difference of as much as several feet and many thousands of dollars in increased development cost.

The City of Houston Public Works & Engineering Department, on request of the Mayor, drafted its changes to Chapter 19 of the City of Houston Code of Ordinances. After a great deal of debate, the City Council passed these changes with some amendments on April 3rd, 2018 and will go into effect on September 1st, 2018. These modifications reflect the effort of the City to create permitting regulations that help prevent or mitigate flooding in our communities.

Floodplain Permitting

When a development is proposed within the regulatory floodplain and Special Flood Hazard Area (SFHA) in the City of Houston, it must secure a Floodplain Development Permit before being completing a plat as well as a building, site, or demolition permit. These permits are reviewed and enforced by the City of Houston’s Floodplain Management Office (FMO), and carry a fee that ranges from as little as $110 to as much as $2,697.

So what are the changes?

2018 Houston Floodplain Cheatsheet
The City of Houston Floodplain Criteria Update goes into effect September 1, 2018. Click here for the PDF version.

Regulated Area

Under existing regulations, floodplain development permits and guidelines are only required on properties that are entirely or partially within the 100-year floodplain and floodway. With this change, properties within the 500-year floodplain in addition to the 100-year will have these regulations enforced.

Elevation Required

The code has increased the elevation required of a finished floor elevation (FFE) of a proposed building or addition to be at or above the 500-year base flood elevation (BFE) plus 2 feet when it was previously only required to meet or exceed the 100-year BFE plus 1 foot.

Zero Net Fill

The City enforces a “No New Fill” regulation for earthwork, paving, building, and grading within the regulated area. This requires that, within the property boundaries, no additional net fill may be added to the floodplain. This does not prohibit earthwork within the floodplain, only that any addition of fill to this area be equivalently balanced with a cut elsewhere on the property within this area.

Previously this was only within the 100-year floodplain, now it is enforced in both the 500-year and 100-year.


The City of Houston will continue to allow any type of foundation in the 100-year or 500-year floodplain. This differs from the changes that Harris County made to its floodplain regulations, which specifies pier & beam.

Substantial Improvements

Developments and redevelopments proposing a substantial improvement to a structure will only be required to follow these updated regulations if they reside within the 100-year floodplain. The FFE will be required to meet or exceed the 500-year BFE plus two feet. A substantial improvement is defined as any rehabilitation, reconstruction, or addition, the cost of which equals or exceeds 50% of the market value of the structure.

What’s Next

With the approval of the City Council and Mayor, these regulations go into effect September 1, 2018. Many developers and residential development organizations have also voiced mixed support for this change, citing the increased safety and welfare of future developments from flooding but also its impact on development cost within the region.

If your development is within the floodplain, there are methods of removing it from special flood hazard area.

Many cities in this area use or draw from the City of Houston and Harris County development criteria in lieu of their own floodplain regulations and may update their own to reflect similar changes. If you are pursuing development in the greater Houston metropolitan area, contact one of our consultants to help you determine what floodplain regulations apply.

If you have a development within Houston metropolitan area and have questions about the floodplain regulations that apply to your property, contact our floodplain permitting experts at BIG RED DOG at 1-877-733-3642 and we will walk you through the process.