In 2017, the analyzed ZPWiK company operated a 486.3 km-long water supply network made mainly of PEHD (76.3%) and 85% of networks up to 20 years old. Most of the failures in the water supply system are due to corrosion of steel pipes and construction work. In recent years, the research shows the failure rate of systemic lowering, and so from 2.33 failure / km year in 2012 to 1.76 failure / km year in 2017 failure / km year. Mostfailures are removed within 8 hours, but you can see that since 2015 the number of difficult failures to be removed in more than 13 hours has been on a yearly basis increasing. Despite the high failure rate, the level of losses is relatively low and decreases from 11.36% in 2012 to 8.75% in 2017, which, compared to the data of the Polish Waterworks Chamber of Commerce (IGWP), is a very good result. The good results obtained are related to the renewal of network materials, the purchase and use of new equipment for locating and removing failures, and the continuous expanded and analyzed monitoring of work as well as the reduction of pressure in the analyzed water supply network.