Penelitian ini bertujuan untuk menentukan konsentrasi logam berat, suhu, pH, konduktivitas listrik, total padatan terlarut (TDS) dan total padatan tersuspensi (TSS) pada sampel air muara Sungai Batang Arau. Nilai konsentrasi logam berat diukur menggunakan alat inductively coupled plasma (ICP), suhu diukur menggunakan termometer, pH diukur menggunakan pH meter, konduktivitas listrik diukur menggunakan konduktiviti meter, TDS dan TSS ditentukan menggunakan metode gravimerti. Dari hasil penelitian diperoleh nilai rata-rata rata-rata suhu sebesar 28,52 ℃. Nilai rata-rata pH sebesar 6,76. Nilai rata-rata konduktivitas listrik sebesar 176,43 µS/cm. Nilai rata-rata TDS sebesar 1040,5 ppm. Berdasarkan PP. No. 82 Tahun 2001 nilai rata-rata TDS di muara Sungai batang Arau telah melebihi standar baku mutu air kelas II yaitu sebesar 1000 mg/l. Nilai rata-rata TSS sebesar 204,9 ppm, nilai rata-rata TSS juga telah melebihi baku mutu PP. No. 82 Tahun 2001 kelas II yaitu sebesar 50 mg/l. Nilai kosentrasi logam berat Cd, Cu, dan Hg di muara Sungai Batang Arau telah melebihi baku mutu yang ditetapkan PP. No. 82 Tahun 2001. Dari hasil yang didapatkan dapat disimpulkan bahwa kualitas air di muara Batang Arau telah terjadi pencemaran. This study aims to determine the concentration of heavy metals, temperature, pH, electrical conductivity, totally dissolved solids (TDS) and totally suspended solids (TSS) in the estuary samples of the Batang Arau River. The value of heavy metal concentration was measured using an inductively coupled plasma (ICP), temperature was measured using a thermometer, pH was measured using a pH meter, electrical conductivity was measured using a conductivity meter, TDS and TSS were determined using the gravimerity method. From the results of the study, the average value of the temperature was 28.52. The average value of pH is 6.76. The average value of electrical conductivity is 176.43 S/cm. The average value of TDS is 1040.5 ppm. Based on PP. No. 82 of 2001 the average TDS value at the estuary of the Batang Arau River has exceeded the class II water quality standard, which is 1000 mg/l. The average TSS value is 204.9 ppm, the TSS average value has also exceeded the PP quality standard. No. 82 of 2001 class II that is equal to 50 mg/l. The concentration values of Cd, Cu, and Hg heavy metals in the Batang Arau River estuary have exceeded the quality standards set by PP. No. 82 of 2001. From the results obtained, it can be concluded that the water quality in the Batang Arau estuary has been polluted.