Pumping (extraction, purge) wells in the waste may be proposed as part of the design of new landfills to backup the leachate underdrain system. These wells are intended to control the leachate mound after there has been a failure of the underdrain system. Pumping wells in the waste have also been proposed to reduce the height in old landfills that are not engineered with a leachate underdrain system. Equations are developed herein for use in estimating the well radius/spacing required to control the leachate mound to a specified level for a number of different assumed conditions and hence can be used to aid the design engineer in assessing the viability of pumping wells in the waste as a leachate control measure. The equations consider the hydraulic conductivity of the waste and the percolation through the cover. It is shown that leakage through the landfill base can be readily considered provided that the leakage through the base is less than 80% of the percolation into the landfill. Anisotropy of the waste is considered. Correction factors are also presented to account for the effect of a reduction in hydraulic conductivity around the well due to biotic and abiotic clogging. The use of the equations is illustrated by examples.Key words:pumping wells, landfills, leachate control, design, applications, clogging.