The Thorn Run Reservoir in Oakland Township appears low Wednesday after a week of no significant rainfall in the area. Butler County is in the midst of a drier-than-usual month. About 1.4 inches of rain have fallen this month at the Pittsburgh-Butler Regional Airport, according to the National Weather Service. Historically the county gets an average of 3.69 inches of precipitation in September. Based on data from the past 90 days of precipitation, the State Department of Environmental Protection is reporting normal levels of ground water and surface water in the county and has not issued a drought watch.