Capillary rise method is widely used for contact angle determination using Washburn equation. Penetration kinetics of porous media comprised from particles of varying size distribution was investigated. It was found that the penetration kinetics and the validation of Washburn’s theory depend not only on the particle size but also on the pore size distribution. The effect of particle size on contact angles was not observed. In case of bed consisting of wide size distribution particles, the smallest fraction plays a significant role creating the smallest capillaries and allowing for more even porous bed penetration. This increases precision of contact angle measurement. A difference of time between fluid flow through a porous bed and its complete saturation (∆t_sf) was proposed as a new parameter describing capillary size distribution in porous media. It allows for fast estimation of both capillary size distribution in a porous bed and precision of contact angle determination.