In this research, zeta potential technical has been used to limit the scales and biofilm inside cooling towers. To perform this experiment, two towers have been used; one with zeta potential device and the other is working normally as a control. A weekly test on samples at the outlet from the two towers has been conducted. As a result, the total count of bacteria was (4308.7 cfu/ml) on the control tower while the total count of bacteria on the zeta potential tower was (731.5 cfu /ml). The average algae growth has been decreased in zeta potential tower to (110.1 cfu/l) while it was about (153.48 cfu/l) in the control tower. The research focused also on some physical properties such as surface tension which is decreased under the influence of zeta potential, the electrical conductivity is increased in potential tower. Biofilm layer in control tower is found while it's not found in treated cooling with 25 high voltage zeta rod.