Sungai Elo yang terletak di Kabupaten Magelang dimanfaatkan untuk memenuhi kebutuhan seperti pengairan sawah dan rekreasi. Sungai Elo telah mengalami pencemaran akibat limbah pertanian, pemukiman, dan industri. Perlu dilakukan analisis kualitas air untuk mengetahui status pencemarannya dan memberikan rekomendasi guna memperbaiki kualitas air Sungai Elo. Penelitian dilakukan pada Januari 2022. Tujuan penelitian untuk mengetahui konsentrasi kualitas air yang diukur, mengetahui status pencemaran sungai melalui analisis indeks pencemaran, dan mengetahui hubungan melalui korelasi pearson terhadap variabel TSS, BOD, dan amonia. Metode penelitian menggunakan metode survey. Penentuan lokasi sampling terdiri atas tiga stasiun yang dekat area pertanian, pemukiman, dan industri. Metode pengambilan sampel adalah purposive sampling. Penentuan tingkat pencemaran dilakukan melalui analisis indeks pencemaran (IP) serta uji korelasi. Hasil penelitian variabel yang diuji telah memenuhi baku mutu air kelas 2 berdasarkan PP. No. 22 Tahun 2021 kecuali variabel BOD. Hasil analisis indeks pencemaran stasiun 1 hingga 3 berturut-turut sebesar 1.16, 1.85, dan 1.00 termasuk kategori tercemar ringan. Berdasarkan hasil penelitian dapat disimpulkan bahwa variabel kunci yang memberikan kontribusi terjadinya pencemaran adalah BOD. Variabel yang telah diuji tidak memiliki hubungan yang signifikan namun memiliki hubungan lemah hingga sangat kuat berdasarkan kategori nilai pearson correlation.   Elo River is located in Magelang Regency. Elo River is used for human life and has been polluted due to agricultural, residential, and industrial waste, so that necessary to analyze the level of pollution and recommendations to improve the water quality of Elo Rivers. The study was conducted in January 2022. The purpose of this study is to determine the concentration of main and supporting water quality variables, determine the status of river pollution based on TSS, BOD, and ammonia throught pollution index, and determine the relationship between variables TSS, BOD, and ammonia. The research method is by survey methods. Determination of the sampling location consists of three stations adjacent to agricultural, residential, and industrial areas. The sampling method is purposive sampling. Sampling data collection is a spatial method. Measurement of water quality is carried out by measuring main variables and supporting variables. The results of this study that each variable meets the quality standard class 2 PP No. 22 Tahun 2021 except BOD. The results of the pollution index for station 1 to station 3 were 1.16, 1.85, and 1.00 and included in lightly polluted. Based on the result, they concluded that the variable causes pollution is BOD. The variables don’t have a significant relationship but have a weak to very strong relationship based on the pearson correlation category.