Actually I do, only I account for the 50% loss in power in my designs. I build double the layout of boilers, run them half at a time until they reach 50% then run them both on regular water for the same power. Or if the machine can handle running from double the power just plumb them all in and let it simmer down. Inefficient yes but it means I never need to worry about my distilled water running out on my ‘always on’ machines.
I also use wooden pipes to vent unwanted gas like sulfur dioxide when I’m not making acid or early games. 
Haven’t found a way to combat the excess amount of water created by some processes though. No way in GT to output water back into the world and ender bins aren’t easy to get to in early game. Buildcraft has a floodgate that I like to use but I see it as cheating because it’s not GT.