The abundance of water is a typical characteristic of Kuopio, as about a quarter of the city's surface area is water. The vast lake basins make up most of the water surface area.
North Savonia’s largest lake Kallavesi is almost entirely located in the Kuopio area.The surface area of Lake Kallavesi is about 470 km2 making it the 10th largest lake in Finland.
Along with other lakes with the same level lake basins (Suvasvesi, Juurusvesi, Riistavesi and Muuruvesi) it forms the approximately 900 sq.km Iso-Kalla, which is Finland's fifth largest inland basin. Kallavesi is quite shallow with an average depth of only about 8.9 m. The deepest point (about 75 m) can be found in the eastern part of Keski-Kallavesi. Kallavesi is a large humus-poor lake which has had been regulated since 1972. Regulation interval is 1.1 m.
Nilsiä’s biggest lake is Syväri which has an area of 80.7 m2. Syväri is also quite shallow, with an average depth of 7 m and a maximum depth of 41 m. Syväri is a humus-rich lake and has been regulated since 1960 with a regulation interval of 2.45 m.
Maaninkajärvi was formed from a bedrock fracture but in spite of the shallow beaches it is extremely deep. The lake has an average depth of 10.6 m at deepest 70.4 m. The surface area of the lake Maaninkajärvi is 24.4 m2. Maaninkajärvi is also classified as a humus-rich lake.
In addition to large lake basins, there are many smaller lakes and ponds in Kuopio. Many of them are quite shallow and more or less eutrophic due to human activity.
Flowing waters in Kuopio are quite few. The best-known places for rapids are located in Korkeakoski situated in Maaninka and Lastukoski rapids in the river joining Syvär and Vuotjärvi. Korkeakoski is Finland's highest free running rapids.
Springs are places where groundwater is discharged to the surface. As a result of the varying terrain in Kuopio, there is a wealth of springs, some of which are taken into the general water supply. Springs and their environment are also important in terms of biodiversity. Damaging a spring is prohibited by Water Act.