HOUSTON (CBSDFW.COM/AP) — The City of Houston Houston approved a new building regulation that will dictate how high new homes and other structures must be elevated to avoid floodwaters.

The regulation, approved by a vote of 9-7 during a sometimes contentious City Council meeting Wednesday, comes more than seven months after Hurricane Harvey flooded thousands of homes in the nation’s fourth-largest city.

Under the rule, new structures in the 100-year and 500-year flood plains would be constructed 2 feet  above the ground or above the projected water level in a 500-year flood, an event in which 17 to 19 inches of rain falls in 24 hours. There’s a 0.2 percent chance of such an event happening in any given year.

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Floodwater surrounds a home after torrential rains pounded Southeast Texas following Hurricane and Tropical Storm Harvey causing widespread flooding on September 3, 2017 in Orange, Texas. (credit: Scott Olson/Getty Images)

The city’s current rule applies only to property in the 100-year flood plain. It requires that buildings be constructed 1 foot above the water level in a 100-year flood, an event in which 13 to 14 inches of rain falls in a 24 hour period. There’s a 1 percent chance of such an event occurring in any given year.

Mayor Sylvester Turner, who championed the effort, called changing the rule a “defining moment” for the city, parts of which got nearly 50 inches during Harvey last August.

“Can we undo what was done with Harvey? No. Can be build looking forward? Yes,” Turner said. “If it has the probability of letting people know in our city and those who are looking to come that we are taking measures to be stronger, to be more resilient, then that’s positive for the city of Houston.”

City officials say that of the homes in Houston’s flood plains that were damaged by Harvey, more than 80 percent could have been protected had they been built at the height required in the new regulation. Such homes would typically be built on pier and beam foundations that put them above ground.

But critics of the new regulation, including several council members and many home builders, argued the rule will drive up home prices, stifle economic development, was being pushed through too quickly and was an example of government overreach. Houston has long had a culture that’s resistant to regulation and remains the only major U.S. city without zoning.

The Greater Houston Builders Association said the new rule will add more than $32,000 to the cost of an average home. The city estimated the cost to be much lower — about $11,000. Officials say higher construction costs would be offset by insurance savings and by avoiding costs associated with flooding.

Flood maps show that more than 25 percent of Harris County, where Houston is located, is in the 100-year flood plain and more than 33 percent of the county is in the 500-year flood plain.
County officials approved a similar new rule in December.

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)