Wastewater can be characterized as water in which various harmful dissolved substances or dispersed solids can be found. It mostly comes from households and industry and its disposal presents a significant challenge in water management sectors. The problem of wastewater lies precisely in its composition and the consequences it causes. Wastewater treatment is a complex process that separates waste from polluted water, and which results in the production of sludge. In order to reduce possible threats to the environment, nature and humans, it is necessary to purify wastewater to a certain degree before discharging it into receivers. The GIS has a very important and wide application in different areas of society. One of the basic purposes of GIS is to provide enough information to support various decisions, including waste water management. The application of GIS is very important in modeling of watersheds, creating bases for water supply plans, creating bases for determining the most favorable routes for the transport of dangerous goods depending on the location of roads in a basin and protective zones, etc. This paper presents possibilities of using GIS in wastewater management in cities of Križevci, Slavonski Brod and Zagreb.