U.S. homebuilding fell to a one-year low in September as Hurricanes Harvey and Irma disrupted the construction of single-family homes in the South, suggesting that housing probably remained a drag on economic growth in the third quarter.

Housing starts decreased 4.7 percent to a seasonally adjusted annual rate of 1.127 million units, the Commerce Department said on Wednesday. That was the lowest level since September 2016 and followed August’s upwardly revised pace of 1.183 million units.

Groundbreaking tumbled 9.3 percent in the South to the lowest level since October 2015, with single-family homebuilding in the region tumbling 15.3 percent to more than a one-year low. The South accounts for almost half of the nation’s homebuilding.

Building permits fell 4.5 percent to a rate of 1.215 million units in September.

Economists polled by Reuters had forecast housing starts falling to a rate of 1.175 million units last month and building permits falling to a rate of 1.250 million units.

Even before the storms struck, residential construction had almost stagnated this year amid shortages of land and skilled labor as well as rising costs of building materials.

Investment in homebuilding contracted at a 7.3 percent annualized rate in the second quarter, the steepest drop in nearly seven years. As a result, housing subtracted three-tenths of a percentage point from gross domestic product in the April-June quarter.

While economists expect housing starts to rebound in the fourth quarter, they caution that rebuilding in the areas devastated by the hurricanes could pull scarce labor away from other parts of the country and limit gains. The reconstruction effort is also pushing up prices of building materials.

Single-family homebuilding, which accounts for the largest share of the housing market, fell 4.6 percent to a rate of 829,000 units in September. Single-family starts rose in the Northeast, Midwest and West.

Groundbreaking on single-family housing projects has slowed since vaulting to near a 9-1/2-year high in February.

Last month, starts for the volatile multi-family housing segment fell 5.1 percent to a rate of 298,000 units. Single-family home permits rose 2.4 percent, while permits for the construction of multi-family homes dropped 16.1 percent