I can't be the only one that hates walking to the water all the time. So, I propose we get the water to us.
Water distribution infrastructure would consist of four parts: pumping stations, aqueducts, reservoirs and fountains.
Pumping stations are built on underground water source or next to a river or a lake. They take stone, metal, wood and linen for the windmill sails (windmill is a built-in power-source). Pumping stations supply the water to the system.
Aqueducts and reservoirs form one system. They both take stone to build. Aqueducts carry water over long distances, and reservoirs allow you to build fountains in their radius. Aqueducts need to have at least two tiles between their pylons, so carts can pass under them. All connected reservoirs and aqueducts are part of one water system, who's water supply is equal to the number of pumping stations connected, and water quality is the average of all the pumps' water quality.
Fountains are the end where you get the water. They can only be built close to reservoirs, using stones and metal (for piping). You can just right-click one with an empty bucket to get a bucket of water. The number of the fountains you can build in a single water system is limited by the system's water supply, ie you can build one fountain for each pumping station.
I think it's pretty obvious this is heavily inspired by Caesar 3. Anyway, water systems could lead to stuff like poisoning of a water supply etc.