The purpose of the geotechnical investigation is to determine the condition of the proposed site for the on-site water treatment system. Understanding the type of soil and behavior of any given project site is crucial to determine any potential risk that may occur. The results provided by a geotechnical investigation can provide valuable information about the strength of the soil, how much water is in the soil, or whether there would be a need for deep foundation to give extra support to a structure. The geotechnical investigation for this project, consisted of a site exploration that included the digging of two borings (holes on the ground) near the location where the proposed on-site water treatment system will be placed. From the borings, soil samples were collected at various depths until a max depth of 5ft was reached. The soil samples were then taken to the geotechnical laboratory in the CE Department for testing.  The tests were done following the American Society for Testing and Material (ASTM) standards. The following test were conducted: Moisture Content (ASTM D2216), Sieve Analysis and Hydrometer Analysis (ASTM: D421, D422, D1124) and Soil Plasticity Determination by performing an Atterberg Limits test (ASTM D4318). The tests results obtained determined the soil to be well graded sand (SW) and nonplastic. Well graded sand is good for compaction since it has almost no compressibility and expansion and is very stable as a fill material. There will be no need for deep foundation since the soil is strong enough.