The quality of drinking water effects not only human health, but also plays a decisive role in daily life. Although the Taiwan water corporation has improved water quality of Kaohsiung in recent years and most of the random testing results of the drinking water done by the EPB could meet the drinking water standards, many people still lack confidence in the tap water. This study (1) select 500 multi-unit residences from 11 districts in Kaohsiung and survey the water quality of the indirect water supply storage devices to understand the tap water quality of indirect water distribution network in Kaohsiung. (2) Aiming at the inhabitants living in multi-unit residences, a questionnaire about the satisfaction with the tap water in Kaohsiung is undergone by random sampling in order to understand the satisfaction with the tap water of the public. (3) The monitoring values of total trihalomethanes (TTHMs) in tap water distributional network in four seasons from December 2006 to September 2007 are used to analysis the seasonal changes, the equal concentration distribution figure, and the ration of all kinds of compounds of the THMs to the total amounts. The results of above analyses can be offered to Taiwan Water Corporation to make improvement and as the references of following studies. The result of the survey of satisfaction shows that 47% people incline to use tap water as drinking water¡F53% people don¡¦t have confidence in tap water and choose to the bottled water from water stations as drinking water source. 49.1% people living in cluster housing in Kaohsiung consider the quality of tap water common¡F15.4% people are satisfied with the tap water quality and 35.7% people are not satisfied with it. The main reason is the old pipelines, and the secondary reason is about the distasteful water. Most people wish to renew old pipelines as soon as possible, and give priority to strictly control the tap water quality. The analysis result of THMs concentrations shows that the average value of THMs in each district is highest in spring and lowest in autumn, especially in Cianjhen, Siaogang, and Cijin districts. The THMs concentration distribution of Cianjhen district is higher in the spring and winter. The proportion of CHCl3 (chloroform) to total amount of THMs is the highest in the water supply network, and it is also the major source of THMs.