River rapids are classified according to their technical difficulty, established during normal flow. This difficulty can vary depending on the river's flow rate. The following classification was established by the decree of 4 May 1995 from the Ministry of Youth and Sports.

Class I = easy:

Regular course, regular waves, small eddies, simple obstacles.

 

Class II = moderately difficult:

(Open passage) irregular currents, irregular waves, moderate eddies, weak swirls and rapids, simple obstacles in the current, small thresholds.

Class III = difficult:

high irregular waves, large eddies, whirlpools and rapids. Rock outcrop, small waterfalls, various obstacles in the current.

Year 4 = Very difficult

(passage not visible in advance, scouting generally required) large, continuous waves, powerful and fast rollers. Rocks obstructing the current, higher drops with re-circulations.

Class V = extremely difficult

(inevitable reconnaissance) waves, eddies, extremely rapid. Narrow passages, very high drops with difficult entrances and exits.

Class VI = Limit of navigability:

(Generally impossible) possibly navigable depending on water levels. Great risks.