This January has been the Triangle's fifth driest in 80 years of records, reducing runoff into Falls Lake to 11 percent of normal, a federal drought management official said Tuesday.

As a result, Falls Lake, which supplies drinking water to Raleigh and seven other Wake County towns, is down about 8 feet, 8 inches. That leaves 30 percent of the reservoir's designated water supply, said Terry Brown, water control manager at the Wilmington office of the U.S. Army Corps of Engineers, which built and runs the lake.

Adding to the worries, Raleigh's consumption is creeping up.

The city's rolling 30-day average has risen from 39.2 million gallons a day two weeks ago to 40.5 million gallons a day now, said Dale Crisp, the city's public utilities director.

On the basis of the last month's use and assuming no rain, Falls Lake has enough drinking water left to last 109 days -- until May 17, Crisp said.

The city, the corps, and state officials are planning to tap into surplus water at the bottom of the lake if necessary later this year.

Tuesday, the Raleigh City Council is scheduled to discuss restricting water use further, Crisp said. The council is considering whether to ban the power-washing of homes and the watering of plants by hand-held hose, which has been allowed twice a week. Some gardeners, landscapers and pressure washers oppose the restrictions.

North Carolina is in the grips of a periodic dry, warm weather pattern known as La Nina, which has kept the state from emerging from its worst drought in modern times. By the time La Nina wanes this summer, the state is expected to be in its normal hot, dry, seasonal weather pattern.

Without heavy rain in the next two or three months -- which looks unlikely -- the drought could become catastrophic this summer, officials say.