It is better to use offshore pumps at every opportunity pointing straight into the machine.
For many entities in the game, water is required. By using landfill, we can engineer a factory where it's possible to point a offshore pump directly into one of these inputs. This saves us several pipes, typically 3 or 4 per crafting machine.
However, these offshore pumps could possibly have a greater total UPS cost than the saved pipes.
In a test where each map was benchmarked for 100000 ticks, and benchmarked for that duration 3 times, the design using the maximum number of offshore pumps achieved ~109 UPS, where as the design that used as few offshore pumps as required achieved ~98 UPS.
This means that using offshore pumps directly in to fluid inputs should beat piping water. It is not possible to test every design, but there is a good degree of certainty that no design that pipes water beats one that directly inputs it.
The full raw csv data is available at here.
In the future, all fluid designs should input water directly to the appropriate spot.
It's possible, although unlikely, for a different design to have a different result. If you have a different or novel design that you believe could contradict this result, please create an issue on the github.