A few hundred people joined Gov. Sonny Perdue in the vigil, which was held under clear skies, some raising their arms in prayer. Around a dozen protesters from the Atlanta Freethought Society demonstrated against the vigil, arguing it violated the separation of church and state enshrined in the US Constitution.
Perdue, a Republican, has imposed water restrictions in the face of the drought and the lack of rain has provoked a political spat between Georgia, Alabama and Florida over how to use water resources from Lake Lanier in north Georgia.
Environmentalists say part of the water problem is a lack of sufficient conservation measures and uncontrolled urban development in some of the fastest growing areas of the southeast United States.
(Reporting by Matthew Bigg, Editing by Michael Christie and Eric Beech)