Rainfall is an important factor in estimating the event mean concentration (EMC) which is used to quantify the washed-off pollutant concentrations from non-point sources (NSPs). The experimental basin extends from 80m to 180m in altitude and has an catchment area of 5.5ha. Field monitoring for continuous measurements of rainfall and water quality was cinducted over 12 storm events during 2011 using automated sampling methods. Water quality was analyzed with respect to BOD, COD, TOC, SS. The concentrations of total rainfall and pollutants from golf course were measured during rainfall period. As a result, average total rainfall, duration and rainfall intensity were 31.3mm, 9.1hr and 3.7mm/hr, respectively.EMCs were 1.7 to 8.5 mgBOD/L 7.5 to 80.3mgCOD/L, 5.1 TO 25.6mgTOC/L, 2.0 to 167.4mgSS/L for the artificial grassland area and 0.3 to 2.4 mgBOD/L, 2.7 to 6.2mgCOD/L, 1.4 to 9.3mgTOC/L, 4.1 to 138.8mgSS/L for the natural area, respectively. This results showed that the EMCs from the natural grassland were lower than that from the artificial grassland. The first flush effect for non point source pollutants occurred in order of SS>COD>TOC>BOD at the golf course.