In this study, the case of seepage stability evaluation method and the foundation treatment method of the agricultural small dam had installed with the relief well on the soil foundation are intro-duced. The status of agricultural dam was introduced and it was carried out field inspection such as seep-age volume check and drilling investigations. Also, the seepage analysis was performed on the present state of the dam and it was analyzed the seepage stability using uplift pressure. The foundation treatment plan was proposed because of the present state of the dam does not satisfying the seepage stability. In case of the foundation treatment plan, both empirical and numerical methods were performed to determine the optimum seepage control method and it was decided the depth and length of foundation treatment for seepage stability.