This paper investigates urban water supply in British colonial Cairo between 1882 and 1936. It looks at the growing conflict between traditional water carriers (sing. saqqa) and the concessionary Cairo Water Company, which provided filtered water to Cairo’s moneyed classes starting from 1865. The company slightly lowered its rates and installed free water taps in a number of poor neighborhoods only after strenuous negotiations with colonial authority in response to outbreaks of cholera and typhoid fever. The cornerstone of this paper is a controversy concerning the taste and purity of potable water that broke up between 1905 and 1910 when the water company altered its method of intake at the behest of the government, drawing water from artesian wells instead of the Nile. The majority of the Egyptian population of Cairo adamantly refused to drink from the new water supply, reportedly calling it “dead water” and reverting to the water carriers. Government officials, British advisors, and foreign scientists deplored that instead of being recognized as a purely scientific issue regarding chemical and bacteriological qualities, urban water supply became a “sentimental” issue involving the superstitions of the “natives.” Eventually, the government negotiated with the company once again to revert to water drawn directly from the Nile after urban elites and middle class effendis joined the chorus of complaints. I argue that the controversy pitted lay against scientific claims to knowledge. Against expert knowledge that was anchored in trust in science, the unforeseen opposition to the new water supply spoke in the name of a rival epistemology, according to which taste provided direct knowledge of what was healthy. Traditionally seen by many philosophers as the most subjective of the senses, taste became the perplexing site of tenacious resistance to one of the colonial regime’s pet modernizing schemes.