To move fluids from the machines i put an interface on the output (way better than import bus) and storage bus configured with the gas on wherever i want to move it.
Water use Sink and Pipez
Edit: i realized you want an infinite water supply to dump steam and refill boiler with water... Currently i haven't looked into that so i can't say an option for that yet. I'll look into that later today.
Note: Storage Bus is passive so it wont move things which already inside of your ME network. Whatever enters the network will try to move straight to the output of that storage bus, if the container already full it'll enter your network instead, so for that you have to use ways so it won't enter your network and won't affect transfer speed
Edit2: I'm so dumb, ID (integrated dynamics) can be set to inf transfer rate so that would be your water solution. Sink> ID> Reactor
Infinite transfer rate solved