Kontinuirano održavanje kvalitete tople i hladne pitke vode u stambenim građevinama, posebno naglašavajući mikrobiološke zahtjeve za kvalitetom vode, predstavlja veliki izazov za stručnjake iz različitih područja djelovanja. Istovremeno, svi oni dijele i odgovornost za zdravlje ljudi koji tu vodu koriste. Kroz ovaj rad dan je pregled pojave i razvoja patogenih bakterija Legionella spp. u sustavima opskrbe pitkom vodom uz naglasak na podsustav potrošne tople vode. Patogene bakterije iz roda Legionella nalaze se u prirodnim vodotocima i dospijevaju sustavom vodoopskrbe do kućanstava. Predstavljaju opasnost za ljudsko zdravlje izazivajući legionarsku bolest, teški oblik upale pluća, a infekcije najčešće uzrokuje L. pneumophila seroskupine O1. U dišni sustav čovjeka dospijevaju iz kontaminiranog okoliša u obliku vodenog aerosola. Prikazani su zakonski zahtjevi vezani uz kvalitetu pitke vode te navedeni primjeri ograničenja vezani uz prisutnost Legionella spp. koja postoji u nekim državama. Osim toga, prikazana su tehnička rješenja za uspješnu inaktivaciju Legionella spp..; Continuous maintenance of hot and cold drinking water quality in residential buildings, in particular regarding the microbiological requirements for water quality, is a major challenge for professionals from different fields. At the same time, they all also share the responsibility for the health of humans using the water. The paper gives an overview of the occurrence and development of the pathogenic bacteria Legionella spp. in drinking water supply systems, with an emphasis on the subsystem for domestic hot water. The pathogenic bacteria of the genus Legionella can be found in natural watercourses, from which they enter the water supply systems and subsequently the households. They pose a threat to human health, causing Legionnaires’ disease, a severe form of pneumonia, whereas infections are usually caused by L. pneumophila of the serogroup 01. They enter the human respiratory system from the contaminated environment in the form of hydroaerosol. The paper further shows the legal requirements for the quality of drinking water and gives examples of the limitations related to the presence of Legionella spp. that exist in some countries. Additionally, the technical solutions for a successful inactivation of Legionella spp. are also presented.