An aeration device - conventional soil disposal field system was monitored for one year in the Lake of the Ozarks area to assess its treatment efficiency and effect on the water quality of the immediate area. The aeration unit consistently produced a well oxidized effluent (soluble COD=44 mg/L; N03-N=22 mg/L; P04=6. 3 mg /L; SS=l 4 mg /L). Soi1-water samples taken from the tile line and 2 and 5 m down slope indicate that considerable denitrification was occurring but may be decreasing. Little coliform movement was detected. The practice of excavating tile lines into the bedrock was discouraged due to a lack of treatment occurring.Project # G-1235-06 Agreement # 14-08-0001-G-1235-0