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Causing $180B in damage, Hurricane Harvey is quite probably the costliest natural disaster in United States history. Rebuilding has been, and will continue to be, a massive undertaking. There are numerous issues that arise for both homeowners and construction businesses in the wake of natural disaster (check out our Playbook for Disaster Recovery for more on that), but often, regulations are loosened in order to speed up the recovery process.

For those living in the unincorporated areas of Harris County, Texas, tighter regulations on rebuilding have actually just come down. Beginning January 1, residents will now have to build to the current 500-year floodplain. It sounds counterintuitive, but this may be a necessary evil. Houston has experienced a “500-year flood” three times since 2015.

We’ve also got a Disaster Recovery Cheat Sheet if you’re short on time!

Harris County, Texas Enacts New Flood-Related Building Regulations

First, here are a few Harvey factors that led to this regulation:

Clearly, something drastic had to be done. That’s why a little over a week ago the Harris County Commissioners Court unanimously voted for more stringent regulations for flood-plain development. This comes not long after similar federal regulations were set aside. But I’m getting ahead of myself…

What is a “100-year” flood? Or a “500-year” flood?

Stay with me here, but these descriptions have nothing to do with time. Commonly, they’re described as floods that only happen once in 100 (or 500) years. However, they have nothing to do with time and everything to do with probability. A 100-year flood is a flooding event that has a 1 in 100 chance (1%) in a given year. Naturally, a 500-year flood has a 1 in 500 chance (0.2%) of occurring in a given year.

Keep in mind, this is restricted to the geographical area. So a 100-year flood merely refers to the amount of flooding in that given area. So, it’s entirely possible for a flooding event in one state to be considered a 100-year flood and for it to be considered mild flooding in some other location. Hurricane Harvey created a 1000-year flood event in many areas. For those of you doing the math at home, your calculator isn’t wrong – that’s a 0.1% chance in any given year.

Vox has a helpful piece on this topic and Hurricane Harvey.

New Harris County Building Regulations

The new regulations can be found here, courtesy of

First, let’s note that these regulations do not apply to Houston. Houston is in Harris County, but the regulations only apply to unincorporated areas. That may not sound like much, the population of these areas has boomed over the last few decades. In fact, an estimate at the end of 2016 put the population of these areas at 2,030,000.

Anyway, new requirements will be as follows:

  • For those in the floodway, new construction must be at least 3 feet above the 500-year floodplain.
  • For those in the 100 year floodplain, the construction must be built 2 feet above the 500 year floodplain.
  • Also, for those in the 100 year floodplain, new houses will not be able to be build slab-on-grade. Instead, the homes will have to be built on piers.
  • For those in the 500 year floodplain, the first finished floor of a new construction must be at least as high as the 500 year flood level.

Those may sound excessive, but rebuilding only to flood again a few years later is a very real possibility – one that many Harris County owners have already experienced. As CityLab discusses in this article, The House of the Future is Elevated.

Check out our Texas Construction Payment Resources – we’ve got a virtual library for anything you’ll need to know on construction payment in the Lone Star State.

Harris County, Texas Enacts New Flood-Related Building Regulations
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Harris County, Texas Enacts New Flood-Related Building Regulations
Pushed by Hurricane Harvey and other recent floods, Harris County just passed regulations for new constructions in unincorporated areas.
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Lien Law News
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