Manalu, Lely Saskia2021-08-232021-08-232020-09wahyu sari yenihttps://repository.unri.ac.id/handle/123456789/10093This research of Underground Water and Hydrogeochemistry has been done sorrounding the Street Matoa Raya West Sidomulyo, Tampan District using the Geoelectric Method Schlumberger Configuration and water quality test at UPT Health and Environment Laboratory of Riau Province. This research was aimed to identify the subsurface lithology based on resistivity values of rocks in the research area. The number of trajectories were two points with a stretch of 150 m. Geoelectric data processing was done using Microsoft Excel and Progress Software. In the trajectories I the resistivity values range from 181.59-652.54 ohm-m. The lithology of trajectories I consists of gravel, gravel sand, alluvial and sand. In the trajectories 2 resistivity values range from 272.23-1727.52 ohm-m. The lithology of trajectories 2 consists of sandy silt, gravel sand, gabbro. Water quality test using pH parameter shows that the water is acidic (pH<7). Total Dissolved Solid (TDS) levels in the sample were below the drinking water quality threshold, which is<500 mg/l.enGroundwaterResistivityGeoelectricLithologyHydrogeochemistryArticle