Why is potassium permanganate used for purifying drinking water ?

Potassium permanganate (KMnO4) is primarily used in water purification because it is a powerful oxidizing agent [2]. In water treatment, its strong oxidizing properties allow it to effectively remove dissolved iron, manganese, and hydrogen sulfide by converting them into solid particles that can be filtered out [3]. While it possesses some germicidal and disinfectant qualities [1], it is often considered a poor primary disinfectant compared to chlorine and is instead valued for its ability to oxidize organic precursors, control tastes and odors, and eliminate algae. By acting as an oxidant, it reduces the demand for other disinfectants and helps prevent the formation of harmful disinfection by-products like trihalomethanes. Therefore, its fundamental chemical role in the purification process is that of an oxidizing agent [2].

Sources

1. [1] https://pubchem.ncbi.nlm.nih.gov/compound/Potassium-Permanganate
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Formation of coal and petroleum > p. 71
3. [3] https://wgbis.ces.iisc.ac.in/energy/water/paper/drinkingwater/simplemethods/disinfection.html