The purpose of this study is to assess the quality of well water near the Sumompo Final Processing Site (TPA) in Manado. The method used involves in-situ measurements and laboratory analysis at the Manado Industrial Standardization and Services Center Laboratory on well water samples around the Sumompo TPA. Well water sampling was carried out at four different locations, which were classified based on distance from the TPA: sample A: 0 - <100 m, sample B: 100 - <200 m, sample C: 200 - <300 m, and Sample D: 300 - <400 m. The water quality parameters tested included physico-chemical and microbiological parameters, namely Temperature, pH, Total Dissolved Solids (TDS), Nitrate, Nitrite, Ammonia, Dissolved Lead, Dissolved Iron, and E. Coli. The quality standards used for comparison refer to the Minister of Health Regulation (Permenkes) Number 2 of 2023, Permenkes Number 32 of 2017 and Permenkes Number 492 of 2010. Laboratory test results showed that the temperature parameters of all samples were still within the quality standard range (27–33°C), with values between 29–30°C. The pH value was generally close to the lower limit, where only sample A (pH 7) met the quality standard (6.5–8.5), while samples B, C, and D (pH 6) were slightly below the standard. The TDS value showed that only sample A (846 mg/l) exceeded the threshold of <300 mg/l. For nitrate (NO₃⁻) content, samples B (26 mg/l) and D (46 mg/l) exceeded the 20 mg/l quality standard, while nitrite (NO₂⁻) were all still below the maximum limit of 3 mg/l. The concentrations of ammonia (NH₃), lead (Pb), and iron (Fe) in all samples were still within the safe threshold according to the applicable Ministry of Health Regulation standards. However, the results of the E. coli analysis showed significant microbiological contamination, with all samples containing E. coli far above the tolerance limit of 0 CFU/100 ml, especially in sample D (6,455 CFU/100 ml). Based on the Pollution Index (IP) calculation, all well water samples were classified as severely polluted: sample A showed an IP of 14.91, sample B reached 17.91, sample C was 12.86, and sample D (the furthest) recorded the highest IP value, namely 22.29. With a water quality status of being heavily polluted (IP > 10), the well water around the Sumompo TPA is not suitable for consumption. Keywords: Well water quality, Sumompo landfill, water pollution, pollution index Abstrak. Penelitian ini bertujuan untuk menganalisis kualitas air sumur yang berada di sekitar Tempat Pemrosesan Akhir (TPA) Sumompo, Manado. Metode yang digunakan melibatkan pengukuran in-situ dan analisis laboratorium di Laboratorium Balai Standarisasi dan Pelayanan Jasa Industri Manado terhadap sampel air sumur di sekitar TPA Sumompo. Pengambilan sampel air sumur dilakukan di empat lokasi berbeda, yang diklasifikasikan berdasarkan jarak dari TPA: sampel A: 0 - <100 m, sampel B: 100 - <200 m, sampel C: 200 - <300 m, dan Sampel D: 300 - <400 m. Parameter kualitas air yang diuji meliputi parameter fisika-kimia dan mikrobiologi, yaitu Suhu, pH, Total Padatan Terlarut (TDS), Nitrat, Nitrit, Amonia, Timbal terlarut, Besi terlarut, dan E. Coli. Baku mutu yang digunakan untuk perbandingan mengacu pada Peraturan Menteri Kesehatan (Permenkes) Nomor 2 Tahun 2023, Permenkes Nomor 32 Tahun 2017 dan Permenkes Nomor 492 Tahun 2010. Hasil uji laboratorium menunjukkan parameter suhu seluruh sampel masih berada dalam kisaran baku mutu (27–33°C), dengan nilai antara 29–30°C. Nilai pH umumnya mendekati batas bawah, di mana hanya sampel A (pH 7) memenuhi baku mutu (6,5–8,5), sedangkan sampel B, C, dan D (pH 6) berada sedikit di bawah standar. Nilai TDS menunjukkan bahwa hanya sampel A (846 mg/l) melebihi ambang batas <300 mg/l. Untuk kandungan nitrat (NO₃⁻), sampel B (26 mg/l) dan D (46 mg/l) melebihi baku mutu 20 mg/l, sedangkan nitrit (NO₂⁻) seluruhnya masih di bawah batas maksimum 3 mg/l. Konsentrasi amonia (NH₃), timbal (Pb), dan besi (Fe) pada seluruh sampel masih berada dalam ambang batas aman sesuai standar Permenkes yang berlaku. Namun demikian, hasil analisis terhadap E. coli menunjukkan pencemaran mikrobiologis yang signifikan, dengan seluruh sampel mengandung E. coli jauh di atas batas toleransi 0 CFU/100 ml, terutama pada sampel D (6.455 CFU/100 ml). Berdasarkan perhitungan Indeks Pencemaran (IP) seluruh sampel air sumur diklasifikasikan sebagai tercemar Berat: sampel A menunjukkan IP 14,91, sampel B mencapai 17,91, sampel C sebesar 12,86, dan sampel D (terjauh) mencatat nilai IP tertinggi, yaitu 22,29. Dengan status mutu air tercemar berat (IP > 10), air sumur di sekitar TPA Sumompo tersebut tidak layak digunakan untuk dikonsumsi. Kata kunci : Kualitas air sumur, TPA Sumompo, pencemaran air, indeks pencemaran