The rules taking effect Jan. 1 in unincorporated parts of Harris County will increase the required elevation for new homes and other structures to avoid floodwaters. Some new structures could be elevated up to 8 feet higher than current regulations require.
Although the new regulations affect nearly 2 million residents, they don't apply to the nation's fourth-largest city of Houston, which is located in the county. A task force is reviewing the city's stormwater regulations.
They're the first major change in the county's flood plain regulations in nearly 20 years.
Builders must adhere to construction standards within a 500-year floodplain instead of a 100-year floodplain under the regulations approved by Harris County commissioners. A 100-year flood is an inundation so large that it has only a 1 percent chance of happening any given year, while a 500-year flood has a 0.2 percent chance of happening any year.
Harvey was the third 500-year flood event to take place in the Houston area since 2015. The hurricane, which had downgraded to a tropical storm when it hit Houston, inundated some parts of the area with more than 50 inches of rain in late August.
"After the regulations we adopted today, Harris County will have the toughest, the stiffest flood building code regulations in the country," said County Judge Ed Emmett. "Nobody wants to build a home that's going to flood, particularly (with) what we've all gone through over the last two years. So I don't think there's any controversy about it. I think it's going to be a real selling point going forward for the area."
The regulations have received support from local developers, including the Greater Houston Builders Association.
More than 30,600 homes and businesses flooded during Harvey in unincorporated parts of Harris County, said county engineer John Blount.
Emmett, the county's top elected official, said that if the new regulations had been in place before Harvey, "that would have protected the vast majority of homes that got flooded."
Officials say the new regulations could change whenever the Federal Emergency Management Agency's flood maps for the county are updated.
"We can't wait on FEMA to redo all the maps. We need to use what we have and that's why we're erring on the side of caution," Emmett said. "We're getting people well above what we think the flood waters are going to be in the future."
Emmett said the new rules could add thousands of dollars to the price of a new home.
"But people don't want to buy a house that's going to flood," he said. "Whatever the cost is, that's just the cost of doing business if you're going to live in that area."
The new building regulations are part of a 15-point plan Emmett unveiled in October as a way to help prevent future flooding like during Harvey. The plan included new building regulations as well as adding a third reservoir to the northwestern part of the county and buying out or elevating homes in the 100-year flood plain or that have repeatedly flooded.
This story has been corrected to show that Houston is the nation's fourth-largest city, not the third largest.
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