The paper is a synthesis of results of research concerning removal of iron, manganese and ammonia nitrogen from groundwaters in filtration process. Minerals in both natural and modified forms, as: quartz sand, catalytic mineral masses, MZ-10 and Defeman, modified clinoptylolite and processed zeolite named Crystal-Right were applied as filtration materials. Quartz sand bed removed easily precipitable iron and it was applied as the first stage of filtration. Filtration through a bed mass, activated with potassium permanganate (VII) named MZ-10 and through manganese ore named Defeman (battery manganese bed), appeared to be effective process for removal of manganese (second stage of filtration). Active chemical masses reduced also the contents of ammonium nitrogen to some degree. High price of the MZ-10 mineral mass induced the authors of this paper to search for its substitute, with clinoptylolite as the likely candidate. From comparison study of both beds it can be concluded that the MZ-10 catalytic mineral masses is more effective than clinoptylolite in removing manganese and other coloring and turbidity-causing compounds from groundwaters. In respect to iron compounds, clinoptylolite and the MZ-10 bed showed comparable performance. However, in hydraulic terms, clinoptylolite exhibited better characteristics in comparison of both beds. Filtration resistance grew at much higher pace in MZ-10 bed, with a resulting need to apply mechanical rinsing operation more frequently. Despite inferior results obtained with modified clinoptylolite, the cheaper clinoptylolite bed may still be competitive to the MZ-10 catalytic mineral mass. One should expect better performance of the clinoptylolite bed in subsequent filtration cycles, i.e. once natural coats, consisting of manganese dioxide and iron oxides, have developed. Processed zeolite mass, Crystal-Right 100, met high requirements for removing iron and manganese compounds, as well as ammonium nitrogen. In its first filtration cycle, the bed of Crystal-Right 100, was effective in removing iron, ammonium nitrogen as well as, up to a certain moment, manganese as well. In the initial phase of bed operation water hardness became reduced considerably. Regeneration of spent bed with brine restored its purifying qualities only to a certain degree (2nd filtration cycle). Iron was effectively removed over the entire cycle, while the results of removing manganese and ammonium nitrogen were much poorer.