In Rome, where a hard-water supply was the norm, pipework tended to follow the road layout, for ease of access; the gradual accumulation of calcium carbonate in would have led to their more-or-less cyclical replacement.
In Rome, hard-water supply was a particular problem, and pipework tended to follow the road layout, for ease of access. Even so, the gradual accumulation of calcium carbonate in narrower pipes would have led to their more-or-less cyclical replacement.