Cilj ovoga rada bio je procijeniti ekološke čimbenike (temperatura, slobodni rezidualni klor, teški metali) koji utječu na prisutnost L. pneumophila u toploj vodovodnoj vodi. U 153 uzorka tople vode ispitana je prisutnost L. pneumophila, kao i utjecaj ekoloških čimbenika na njihovu prisutnost u vodi. L. pneumophila je dokazana u 24,8% ispitivanih uzoraka. Koncentracije željeza veće su u uzorcima u kojima je nađena L. pneumophila uspoređujući ih s uzorcima u kojima nije bila prisutna, dok su povišene vrijednosti temperatura u negativnoj korelaciji s prisustvom L. pneumophila.. Nije dokazana statistički značajna povezanost cinka (z = 0,855; p = 0,392), mangana (z = 0,283; p = 0,777), bakra (z = 1,66; p = 0,097) i slobodnog rezidualnog klora (z = 0,458; p = 0,648) s prisustvom L. pneumophila.. Istraživanje potvrđuje postavku o povezanosti ekoloških čimbenika, o prisutnosti bakterija L. pneumophila u toploj vodi vodovodnog sustava..; The aim of this paper is to assess whether ecological factors (temperature, free residual chlorine, heavy. metals) influence the presence of L. pneumophila in warm tap water. In 153 samples of warm water, the presence of L. Pneumophila and the influence of ecological factors on its presence in water was tested. L. pneumophila was confirmed in 24.8% analyzed samples. Iron concentrations are higher in the samples in which L. pneumophila was found when compared to the samples where it was not present, whereas increased temperature values are negatively correlated with the presence of L. pneumophila.. A statistically significant relation between zinc (z = 0.855; p = 0.392), manganese (z = 0.283; p = 0.777), copper (z = 1.66; p = 0.097) and free residual chlorine (z = 0.458; p = 0.648) and the presence of L. Pneumophila was not proven.. The investigation confirms the assumption about exstence of a connection between ecological factors and the presence of bacteria L. Pneumophila in warm tap water.