Sustainable water supply system is a necessity in growing communities. This study identified Governments, NGO’s (Donor and Joint Partnership), and Private Sector (Communities) as the three major promoters of public water supply facilities in a developing country like Nigeria. Secondary data retrieved from the National Water Supply and Sanitation database in the six States of South-West Nigeria was used for the study. The Kruskal-Wallis Test was adopted for the data analysis and description which showed an indication of performance mean rank of promoters. The results indicated that the promoters with highest percentages of operational facilities in the six States are: Communities (ranging between 89% and 100%); and NGO’s which comprises of both Joint Partnership between two or more promoters and Donor (ranging between 75% and 100%, and 56%) respectively. The federal government has the highest percentage of non-operational facilities in five of the six States ranging between 46% and 73%. In the other remaining State (Osun), LGA (Local Government Authority) had the highest percentage of non-operational facilities of 34.1%. There were more operational facilities in 50% of the States compared to the non-operational. The non-operational facilities are grounded due to broken down machines, poor construction or lack of maintenance and supervision.