A field sampling programme was carried out at a Vancouver Lower Mainland landfill to study leachate flow and characterization. A water balance and simple hydrogeologic model were developed for the site In order to calculate leachate discharge rates. Details of leachate composition are presented and related to site water input patterns. The interdependance of leachate composition, water input and fill retention time is hypothesized. Implications are presented in terms of site configuration and treatment process design.