Latar belakang: Total Dissolved Solids (TDS) merupakan benda padat terlarut yaitu semua mineral, logam, garam serta anion-kation yang terlarut dalam air. Metode filtrasi dapat menurunkan kadar Total Dissolved Solids (TDS) dan dapat menggunakan media filter arang aktif. Penelitian ini bertujuan untuk mengetahui penurunan kadar Total Dissolved Solids (TDS) dengan perbedaan variasi ketebalan media filter arang aktif.Metode: Penelitian ini bersifat eksperimen dengan desain penelitian pretest-postest without control. Penelitian ini dilakukan dengan 3 perlakuan dan masing-masing perlakuan sebanyak 6 kali pengulangan. Populasi dalam penelitian ini adalah air bersih yang berasal dari sumur di PT. X dengan sampel sebanyak 36 sampel.Hasil: Penurunan kadar Total Dissolved Solids (TDS) pada air bersih menggunakan media filter arang aktif dengan ketebalan 100 cm didapatkan rata–rata 909 mg/l, ketebalan 110 cm didapatkan rata–rata 700,5 mg/l, dan ketebalan 120 cm didapatkan rata–rata 608,8 mg/l.Simpulan: Filter dengan media arang aktif pada tiga ukuran ketebalan yang berbeda efektif menurunkan kadar Total Dissolved Solids (TDS) pada air bersih di Industri Susu X. Peneliti selanjutnya dapat melakukan penelitian lebih lanjut mengenai timelife media filter arang aktif dalam mengadsorpsi kadar Total Dissolved Solids (TDS). ABSTRACTTitle: Differences of Variations in the Thickness of Activated Charcoal Filter Media as Adsorption Media for Filtration Equipment in Reducing Total Dissolved Solids (TDS) Levels in Clean Water in Dairy Industry X, Cinambo District, Bandung CityBackground: Total Dissolved Solids (TDS) are dissolved solids, namely all minerals, metals, salts and anions dissolved in water. Filtration methods can reduce Total Dissolved Solids (TDS) levels and can use activated charcoal filter media. This study aims to determine the decrease in Total Dissolved Solids (TDS) levels with different variations in the thickness of activated charcoal filter media.Method: This research is an experimental research design with pretest-posttest without control. This research was conducted with 3 treatments and each treatment was repeated 6 times. The population in this study is clean water from wells at PT. X with a sample of 36 samples.Result: Reducing Total Dissolved Solids (TDS) levels in clean water using activated charcoal filter media with a thickness of 100 cm obtained an average of 909 mg/l, a thickness of 110 cm obtained an average of 700.5 mg/l, and a thickness of 120 cm obtained an average of an average of 608.8 mg/l. Conclusion: Filters with activated charcoal media at three different thickness sizes are effective according to the levels of Total Dissolved Solids (TDS) in clean water Dairy Industry X. Future researchers can conduct further research regarding the timelife of activated charcoal filter media in adsorption of Total Dissolved Solids (TDS) levels.