ABSTRAK Telah dilakukan penelitian lapisan akuifer di Desa Bak Aghu menggunakan metode resistivitas 2D konfigurasi Wenner-Schlumberger. Tujuan dari penelitian ini untuk menentukan kedalaman lapisan akuifer dan mengatasi kekurangan air bersih di desa Bak Aghu. Akuisisi data dilakukan pada tiga lintasan dengan panjang masing-masing lintasan satu dan dua 224 meter sedangkan lintasan tiga 336 meter. Alat yang digunakan SuperSting R8 dan pengolahan datanya menggunakan software Res2Dinv. Hasil yang diperoleh pada penelitian ini menunjukkan lapisan bawah permukaan desa Bak Aghu terdiri dari batuan andesit, tuffa pasiran, lanau, lempung pasiran dan lempung. Lintasan yang paling berpotensi akuifer adalah lintasan tiga yang berupa lapisan pasir dengan kedalaman 23 – 60 meter dari permukaan. Kata Kunci: metode resistivitas, konfigurasi Wenner-Schlumberger, akuifer, Bak Aghu. ABSTRACT It has been conducted a study to investigate the aquifer at Bak Aghu village by using Wenner-Schlumberger array of 2D Resistivity method. The purpose of this study is to determine the aquifer depth and to help the shortage of water at Bak Aghu Village. The data acquisition were carried out using three survey lines, 224 meters for line one and line two and 336 meters for line three. Equipment used for this study to record resistivity data is SuperSting R8 and data processing was done using Res2Dinv software. The research result shows the subsurface structure at Bak Aghu village which consist of andesite, sandy tuffa, silt, sandy clay and clay. A line that is very potential for aquifer existence is line three that consist of sand layer with 23 to 60 meters depth from subsurface. Keywords: resistivity method, Wenner-Schlumberger configuration, aquifer, Bak Aghu.