There is few experimental data on the quality of biodiesel and effect of soluble water on itsquality. As reported by ASTM, specification of water content in the biodiesel is 500 mg/kg.Although meeting the specification after production of biodiesel is achievable with some dehy-dration process, but absorption of water from environment to the biodiesel which is related tothe temperature and composition of biodiesel is almost important during transportation and