According to some investigators, the flocculation mechanism is based on action of chemical bonding forces. Little emphasis has been placed on the possibility that the flocculant might alter the make-up of the double layer thereby reducing electrostatic repulsive forces between particles and flocs. Behavior of the calculated electrokinetic or 'Zeta' potential reflects change in the stability of a suspension. Flocculation behavior can therefore be correlated with a Zeta potential. One means of estimating the Zeta potential is from microelectrophoresis measurements. The report shows that, by measuring the floc bed depth and total electrical resistance of the streaming potential cell, as well as the streaming potential and its corresponding pressure difference driving force, a control factor, valid over the potable water range, can be calculated for each flocculation system investigated. (Author)