Medvednica is abundant with streams and springs. Rainfall pours down rapidly, depending on the slope and terrain composition. On watertight slates there is more water, and springs occur, for example Bliznec stream which is a deep stream valley. On calcareous and dolomite rocks which are water permeable, surface water drainage does not occur, but typical carst forms are formed (for example, wider area of Ponikve).

Springs on Medvednica generally have smaller capacity, but are numerous, which enables water supply of smaller settlements, and for the smaller part are included in city water supply system. The majority springs above the elevation 750 m in wooded areas, so there is no danger of erosion in these areas, which usually needs to be especially considered.

Abundance of springs, which reflects in the stream flow, is conditioned by precipitation. In the central part of the side exposed to sun (southern side of Medvednica) there is about 60 springs, which are appropriated for exploitation in the water supply system of Sljeme zone, and have approximate available water quantity of 18 l/sec.

In Medvednica area there are a few thermal springs of various quality and abundance (Stubičke Toplice, Zelina, Gornja Dubravica). They occur on faults, where water that is heated in the depths of the earth emerges on the surface while passing through carbonate rocks. Such are Sutinska Vrela near Podsused.

Slani potok (Salt stream) springs on Zagorje side of Medvednica, and its name comes from the salty taste of the water from NaCl salt. It is known since 1347, when salt was excavated from wells called “šokoti” (from Hungarian word “sokut” –salt well), but production was low, and excavation of salt soon ceased.

Medvednica streams have a distinctly mountain character; upper flow is steep and lower slanted.

Owing to numerous springs and collection of rainfall from nearby slopes, rivers of the southern side of Medvednica are rich with water during the whole year. Richness of waters is evidenced by many former mills, especially on Miroševac stream which gets its water from numerous confluents in upper parts of Medvednica: Ribnjak, Jelovčina, Suhodol, Trnava, Bidrovac. In the central flow of Trnave the strongest well on Medvednica – Tisova peč – is located . Today this well is partially regulated and used for water supply.

Markuševac stream springs near climbers' lodging «Puntijarka» on elevation 991 m. Two strong springs are located near Markuševac stream, Mrzljak Srednji and Mrzljak Donji. It ends by inflowing into Štefanec stream.

Bliznec stream is of special significance for Zagreb , because of Maksimir Park . It springs in the highest region of Medvednica, between peak Sljeme 1033 m and Puntijarka 991 m, close to a 12 m high rock called Forester's grave. The stream doesn't have one spring, but the water is collected from a series of steep ditches.

Streams Medveščak, Kraljevac, Zelengaj and Jelenovac , reach the very city core while descending down southern slopes of Medvednica. In the valley of Medveščak there is a strong spring and a famous outings spot Kraljičin zdenac .

Kuniščak collects water from lower regions of Medvednica. Stream Črnomerec in the upper part consists of two streams: Črnomerec and Mrzlak which in the lower part flow under a common name Črnomerec. Sporadically one can see beautiful natural cascades.

On the western part of southern slope of Medvednica flow Kustošak, Mikulić potok and Vrapčak.

Through Ponikve meadow flow three streams . The biggest one is Jezeranec, than Javorščak , which springs at «Jambrišakovo vrelo» beneath a small cave on Ponikve. This is the largest and most beautiful wellspring on Ponikve. Between these two streams flows Slivnjak stream.

Jambrišekovo vrelo

In river Krapina basin, within municipality Zaprešić, there are five important rivers : Ivaniščak, Kutinci, Poljanica , Bistra and Dedina.

Bistra is the larges and riches stream, it gets its water from a strong spring Mrzla voda . It is interesting that next to the stream there is a series of sulphuric wells which give to this area a specific value in health sense. Total length of Bistra stream is 11 km. Dedina is the end stream on the eastern side of municipality Zaprešić .

Streams are endangered by construction in the neighborhood, aggressive hydro-technical measures which change their appearance, polluted fecal and other waste water, and disposal of bulk waste. Especially endangered are streams in carst area because all surface pollution filtrates by precipitation in the underground, and in that way pollutes rivers. Costal vegetation develops next to streams, especially forest community of common alder with sedge ( Carex brizoides L.). Stream fauna is significant since it includes many endangered and endemic taxa.