In 2015, UNICEF and the World Health Organization reported that over 90% of the world’s population used improved drinking water sources. But new research suggests the indicators used by UNICEF/WHO grossly overestimated the state of water access, especially in cities of the global south. Analysis of 15 cities shows that vast segments of the urban population in the global south lack access to safe, reliable and affordable water. On average, almost half of all households in the studied cities lacked still lack access to piped utility water. The new analysis featured in this paper also illustrates that piped utility water is the least expensive option for most households. But reliability is crucial. Among those households that were connected to piped water in the analyzed cities, most received intermittent service, which results in contaminated water. Households that are not connected rely on self-provision or private water vendors, which are up to 50 times more expensive than public water.