As a result primarily of rainfall infiltration through waste materials, all landfill sites in the United Kingdom will produce leachate. A procedure for estimating rainfall infiltration through landfill sites founded on readily and cheaply available Meteorological Office data is presented. This accounts for the distribution of rainfall throughout the year and shows that for a site in south Essex, between 14 and 34% (average 24%) of annual rainfall infiltrated in the past eight years. Winter and summer operational stategies which may minimize the production of leachate are summarized. These are based on minimizing rainfall infiltration in winter months and taking up the shortfall between potential evapotranspiration and actual evapotranspiration in summer months.