This paper presents a targeted survey of Roman and Byzantine hydraulic infrastructure as it survived in cities of the Umayyad Levant. While the baths and saqiyas of the desert castles, as at Qusayr Amra, have been comparatively well known since the early twentieth century, new archaeology over the last thirty years has revealed the remarkable range and texture of water in urban settlements of the Levant after the Islamic conquests. This paper demarcates a spectrum of infrastructural outcomes which revolved, it is argued, around the administrative position of the city in question, as well as upon the role of cities writ large as loci for tax collection. For instance: sea-side Caesarea Maritima lost its position as Roman Palestina Prima’s provincial capital after the siege of 640, and while archaeological evidence suggests that its Roman aqueducts were in disrepair after the sixth century, their supplies were gradually replaced by new wells and cisterns in the vicinity of new houses and alongside revamped public areas, including the mosque built atop the former Temple / Church Platform at the city’s center. On the other hand, a system of street-side fountains at Jerash built in the Roman period were maintained for public areas (including churches) until the earthquake of 749 CE, even as a downtown bath complex was demolished and replaced by a congregational mosque. At Ramla or Resafa, newly created aqueducts and pointed-arch vaulted cisterns reveal both technological continuities and new syntheses repurposed for the evolving social environment.