Drainage phenomena on the conventional fourdrinier table can be divided into two distinct zones based on the drainage mechanisms involved. In the forming zone, natural drainage is the principal water removal mechanism, while in the vacuum zone vacuum dewatering displaces water in the wet sheet with air. In this study to investigate the influence of polyelectrolyte addition on natural and vacuum dewatering a vacuum drainage tester was developed and used. Addition of PAM decreased the dryness of the wet sheet after vacuum dewatering since substantial reduction in vacuum level occurred due to flocculation of fibers. Addition of PAM, however, increased the wet web dryness when the fines content of the stock is greater than 35% indicating the presence of fines reduced the air permeability of the wet web to increase its response to vacuum dewatering. On the other hand, PEI, which flocculates the fibers and fines via patch formation, showed little impact on the drainage characteristics of the stocks.