Use of Arno in the late 1400's:
A: Shipping by water was expensive. It is likely that food arrived to Florence by less expensive mule or ox carts from local farms and estates.
Did the Arno supply fish and or crustaceans in meaningful quantities? A famous woodcut of the city dated around 1500 provides some clues to what the city MAY have looked like. The woodcut served as a basis for a very large map that was painted in the 1800's and is on display free of charge on the ground floor of the Palazzo Vecchio (excerpts below).
The map portrays various uses for the Arno that could be accurate but must be further researched. The map suggests that there was fishing activity downstream at the western end of the city. Is it true? It shows a man with a net and on shore others seem to be collecting something from the shore.
The suggestion that there was fishing downstream of the city and its industry raises serious questions about the quality of the water. Dysentary and other health issues were prevalent in the city. This food-harvesting activity would have been downstream of the wool mills that washed and dyed their wool in the river. The water supply also carried away human waste and trash carried by the city's streets into the river.
One factor encouraging the downstream location of fish might have the custom of the butchers then located on the Ponte Vecchio to discard their meat scraps into the river.
A: Did the Arno supply drinking water to those living on its banks?
Water drawn from wells was the chief supply of fresh water for the city, but it is probable that some people may have still drank river water.
By the close of the 15th century the Arno's water was no longer drinkable within the confines of the city. Unfortunately that didn't necessarily stop people from drinking it and the resulting dystentary was sometimes fatal. The best option of water from the Arno would have been outside the city gates upriver, west and slightly north of the wool works and mills that started near Santa Croce and extended to the riverbanks outside the gates.
Within the city the wealthier homes had their own wells. Some courtyards had cisterns below that gathered runoff water. It is likely that there were also public well, but i have yet to confirm this.
A Pre-Renaissance example of Florentice Architecture and plumbing?
Davanzati Palazzo is a remarkable medieval home in Florence that is currently maintained as a museum to provide a unique sliver of genuine pre-Renaissance architecture and interior design.
A great stone atrium dominates the house with a wall that runs up the height of the mansion on the left side. Down the length of the wall, there is a bony system of pipes that runs a crooked route to the ground floor. I speculate this was to provide water to the household from a cistern on the roof or another rain collecting system. The pipe system could also date to a later period. I will follow up on this.