researches have been done on scouring, an appropriate equation to predict scour at bridges foundation has not been presented yet. In this research, an experimental study on clear water scour at pile groups under steady flow conditions at threshold velocity is presented. Experiments were conducted in a flume of 46 m length, 1.52 m width, and 1.9 m depth, and uniform bed material of median particle size of 0.8 mm. The objectives of this study were to present changes in scour at multiple piles due to the pile arrangements and present an empirical relationship to estimate the scour depth at multiple piles with different arrangements. Wide ranges of pile group arrangements were studied with pile diameters of 60 mm and 42 mm. The number of piles in line with flow (m) and normal to flow (n) were regularly increased at each successive experiment. In total, 40 experiments were carried out using possible arrangements of pile group where maximum number of n and m were 4 and 10 respectively. It was observed that the scour at pile group is affected by pile arrangements. The collected data were used to propose a new empirical equation to compute effects of the studied variables (m and n). The output of this research can be used to improve the pile group arrangement procedure to estimate local scour depth at multiple and complex piers.