Herbicides, detergents, phenols, solvents and polynuclear aromatic hydrocarbons belong to organic impurities most often encountered in waters. Polynuclear aromatic hydrocarbons are specially dangerous because they are accumulated in organisms and some of them reveal the following effects: cancerigenic, cocancerigenic, mutagenic and teratogenic. Unfortunately, the standards for drinking waters, valid now in Poland, do not mention any specific group of organic compounds which should be determined. Meanwhile in many European countries appropriate standards have been established and the admissible concentrations of hydrocarbons in drinking waters are determined.