COLUMBIA, S.C. - Gov. Mark Sanford is encouraging South Carolina residents to voluntarily conserve water so water restrictions don't become mandatory.

Officials say a drought gripping the state continues to worsen. The Department of Natural Resources says the worst conditions are in the Upstate, where some wells have gone dry and Lakes Hartwell and Thurmond along the Georgia state line are already 10 feet below where they should be.

A special drought committee will meet next month and could suggest mandatory water restrictions for nonessential activities like washing cars, watering lawns and filling swimming pools.

The committee says five northwestern counties are in an extreme drought, which is the worst category.