Because the water from the lagoon in which Braavos is located is brackish and briny, the canal water is not drinkable without first boiling it. Thus, the Braavosi built the sweetwater river to supply themselves with clean water. A roadway supported by three tiers of arches traveling from the south, looming above the canals and houses, it brings fresh water from the mainland across the mudflats and the briny shallows. Rich men pipe it directly into their homes, while commoners fill buckets at public fountains. The sweetwater river enters the city on the south side of the city, crossing the Long Canal and Green Canal, before ending at the Moon Pool.