Abstract: Heavy metal contamination in water is very dangerous because of its toxicity. Exposure of heavy metal can accumulate in the body tissues of living things lived there. Cadmium (Cd), Lead (Pb) and Mercury (Hg) are heavy metals which highly toxic compared to other heavy metals. Carcinogenic properties of these metals potentially cause cancer in various organs. Kaligarang river is one of the rivers in Semarang which include to the target of Program Kali Bersih (Clean River Program). Its flow is met with the flow of Kreo river which is contamined by heavy metals.