Loudoun County officials lifted mandatory water restrictions yesterday that began in August but asked residents to continue voluntary conservation measures.

The combination of steady rain showers in recent days and the onset of cooler temperatures prompted the change, although officials remain concerned about the long-term effects of the prolonged drought, said Dale C. Hammes, general manager of the Loudoun County Sanitation Authority.

Recent rains "have had a very positive effect on our water supply system," Hammes said. "With the summer behind us, I believe it is prudent to lift the mandatory restrictions at this time."

Loudoun's decision comes a week after Maryland Gov. Parris N. Glendening (D) lifted statewide water usage restrictions that were imposed Aug. 4. Maryland officials say the state is emerging from the drought, but they also are asking residents to continue voluntary conservation.

Loudoun, in late July, became the first county in the Washington area to approve mandatory restrictions, including limits on washing cars, watering lawns and serving water in restaurants. The restrictions applied to the 30,000 households and businesses in eastern Loudoun served by the authority.

The sheriff's department issued 63 warnings but no citations, Deputy Ed Pifer said.

As of late August, rainfall at Dulles International Airport was four inches below normal for the year, but the shortage was exacerbated because the last few months of 1998 also were dry, according to the National Weather Service. Storms that began over the Labor Day weekend and continued into Thursday dumped 3.03 inches of rain in Leesburg. Hammes said nearly four inches of rain has fallen at the authority's maintenance building in Ashburn since Sept. 4.

Officials in Middleburg--the only Loudoun town with its own mandatory restrictions--said they will keep limits in place for the time being.

Hammes said Loudoun, unlike neighboring jurisdictions, was forced to turn to mandatory restrictions because much of its drinking water comes from Goose Creek, which had a significantly reduced flow this summer. Rain has replenished the creek, Hammes said, increasing its flow from only 4 million gallons a day in mid-August to 140 million gallons yesterday. The conditions in Loudoun's Beaverdam Reservoir also have improved, but it remains 13 feet below normal.

Hammes also has noted that water usage tends to decrease when the weather turns cooler because people are using less water for their lawns.

The authority is asking residents to continue conservation measures that call for people with even-numbered addresses to water on even-numbered dates and those with odd-numbered addresses to water on odd-numbered dates.

Authority officials said they are closely watching the water supply and may have to return to mandatory restrictions if the autumn weather turns dry. Forecasters are predicting Leesburg will get more rain Tuesday and Wednesday as a cold front moves in from the Northern Plains.

Loudoun Supervisor Scott K. York (R-Sterling) said he was cautiously optimistic that conditions will continue to improve and that residents will keep demand low.

"This rain by no means has broken the drought," York said. "We are going to keep close watch. We'll have to play it by ear and see what happens."

Staff writer Dana Hedgpeth contributed to this report.