Private well water supplies can pose a risk to health unless they are properly protected and maintained. This study focuses on the physicochemical and microbial analysis of deep well water in Barangay Mabalbalino, San Carlos City, Pangasinan. Organoleptic testing determined the physical characteristic of water samples in terms of odor, color, and taste respectively. In physicochemical analysis, parameters were delimited to Total Dissolved Solids (TDS), Salinity, Potential of Hydrogen (pH) and Nitrate. Based on the results, the TDS of four water samples failed to pass the permissible limit set by the Philippines National Standard for Drinking Water 2017 (PSNDW 2017). For salinity, there is no specific reference value used, pH and Nitrate both passed the permissible limit. In microbial analysis, since all water samples are untreated there is no specific reference value for Total Coliform and Heterotrophic Plate Count. For Thermotolerant Coliform, only area three passed the permissible limit set by the PSNDW 2017, while one, two and four failed to pass the permissible limit. Deep well water in Mabalbalino, San Carlos City is allowed for drinking but in terms of water quality in accordance with PNSDW 2017, deep well water is not potable for drinking. Deep well water should be tested every year for physicochemical and monthly for microbiological.