Abstract: An improved sewage grinder pump tank inclusive of an upper tank portion formed as a cylindrical section of DR 32.5 HDPE, a lid assembly covering the upper tank portion, a lower tank portion similar to the upper tank portion, a pump platform section in communication with the upper tank portion and lower tank portion and forming a platform there between for mounting a grinder pump, and a base formed as a concave molded section for mating with the lower tank portion. The pump platform section is butt fused between the upper tank portion and the lower tank portion, and the base is butt fused to the open end of the lower tank portion. The butt fusion amalgamates the parts into one piece and avoids imperfections, thereby improving structural integrity. In addition, the grinder pump tank simplifies installation, and reduces cost.