The Kumiela Canal is the oldest long, open, earthen aqueduct built on the territory of the Teutonic state which is mentioned in sources. Constructed in the first half of the thirteenth century, it was fed by the Kumiela River, flowing out of the heart of the Elbląg Upland. The purpose of this four‑kilometre‑long artificial watercourse was to bring water to the developing city of Elbląg: for household, hygiene, defence and fire‑fighting needs of the city’s inhabitants. The canal supplied water to the city’s waterworks and baths; its water also powered the mills located in the suburbs and filled the castle moat. The important role of the canal was evidenced by ordinances issued by city officials to keep its water clean.
This article aims to present the significance of the Kumiela Canal for the inhabitants of medieval Elbląg in the light of information from, among other sources, the city’s account books. The issue of two other, lesser‑known watercourses flowing in the vicinity of medieval Elbląg, namely the Hoppenbeke and the Hundebeke, is also addressed. There is no doubt that water was, and still is, an elementary example of a common good, and that its provision and care for its purity was a manifestation of the rulers’ concern for the life, health and comfort of the inhabitants, as well as an important contribution to the development of the city.