ABSTRACT Passive solar stills are simple and economic water treatment systems which apply natural hydrological cycle to transform brackish and saline water into freshwater useful to the society. This paper reports the performance of aTwin Wedge Solar Still with concrete basin (TWSS(CONC)) designed suitably for implementation in Green Building Applications. Through an experimental investigation, the performance of this TWSSsystem is compared with that of Conventional Solar Still (CSS) and the effect of including an Aluminum liner to the concrete basin of TWSS(TWSS(CONC+Al)) is also studied. The experimentation was carried out at South Indian location of Kattankulathur (Longitude/Latitude: 88.6241° E/24.3636° N), on a summer day. The distillate yields of the CSS, TWSS(CONC)and TWSS(CONC+Al) were obtained as 1.90 l/m2, 2.77 l/m2 and 4.17 l/m2, correspondingly. The thermal efficiency of TWSS(CONC+Al), was 1.8 times more than TWSS(CONC) and 2.6 times more than the CSS. The TWSS(CONC+Al), delivered freshwater at the cost of $ 0.027 per liter. The Twin Wedge shaped glass lid allowed more solar radiation to be received by the basin as well as increased the condensation surface. The aluminum lining inTWSS(CONC+Al) aided proper distribution of heat in the basin and increased the evaporation rate. The thermal energy which was stockpiled in the concrete basin enabled to maintain a significant difference between thebasin water and condensing surface temperatures during the hours when the solar radiation intensity was low. The payback time period for TWSS(CONC+Al)was estimated to be only 9 months.