India is the second largest consumer of sand, and the production of manufactured sand (M-sand) has exceeded an annual target of 850 million tons. Its annual demand is expanding at a rate of 15–20%. M-sand production involves different sand-washing techniques which lead to the slurry-type waste material (sand washing waste or SWW). The innovative usage of recycled materials is the priority to minimize the depletion of natural resources. The suitability analysis of this SWW as reinforced fill is studied in this research based on the guidelines given in the standards. The different proportions of SWW (0, 20, 40, 50, 60, 80, and 100%) are blended with natural sand. The index properties, compaction characteristics (heavy compaction), permeability (falling head method), and drained shear strength parameters (direct shear test) were studied for all the mix proportions. Based on the test results, it is observed that the non-plastic fine content increases with an increase in SWW, and more than 90% of fines are silt with a coefficient of uniformity greater than 2. The permeability values of different mixes lie in the range of silt. Up to 60% addition of SWW, there is only a marginal increase in OMC for SWW–sand mixtures, and the drained friction angle observed for those mixtures is greater than 30 degrees. Based on the reinforced fill criteria (IRC SP-102), 60% of SWW can be replaced with natural sand and sustainably used as non-plastic fill material in reinforced (polymeric) earthen structures.