This paper presents a theoretical analysis of a tilted wick solar still with a flat plate bottom reflector extending from the lower edge of the still on four days (the spring and autumn equinox and summer and winter solstices) at 30 degrees N latitude when the still's inclination is fixed at 30 degrees and the reflector's length is the same as the still's length. We propose a geometrical model to calculate the solar radiation reflected by the bottom reflector and then absorbed on the evaporating wick. We also performed a numerical analysis of heat and mass transfer in the still. We found that the bottom reflector can reflect the sunrays to the evaporating wick and increase distillate productivity of the tilted wick still when the reflector's inclination is larger than about 15 degrees on the spring and autumn equinox and winter solstice, and 25 degrees on the summer solstice, and the average distillate value for four days is greatest when the reflector's inclination is about 35 degrees and would be about 13% greater than that of a conventional tilted wick still. (C) 2011 Elsevier B.V. All rights reserved.