An account is given of the status of monitoring in a new legal system for environmental protection in Poland. The legal acts such as Environmental Protection Law, Water Law and resulting from it the Ordinance of the Ministry of Environment, which relate to the EU Water Framework Directives (2000/60/EC) were introduced to the Polish legal system. They present the principles by which state monitoring of the environment should operate in Poland and thus the source of information about water quality. The present article deals with continuation of the biological studies for monitoring rivers, including the relevance of a computer programme for this purpose. The article concludes with and assessment of how the quality of Polish rivers will be improved as a result of this legislation.