The reservoir is a multiblock structure that outputs water much like a 4 water sources would in vanilla. It should be built in a 2x2x1 formation to form a square, which allows for compact water generation.
|Ingredients||Input » Output|
| Any Glass + Fused Quartz +
see: Crafting Guide
While a reservoir can hold a bucket of liquid on its own, this is not its main purpose. Simply place 4 reservoirs in a 2x2x1 pattern, in any direction, and it will form a multiblock structure.
Upon filling this structure with 2 buckets of water, it will fill the other 2 automatically.
Water may be pumped out by any means.
In addition to being able to pump water out, the reservoir structure can pump it out itself! Simply right-click with a Yeta Wrench or any other Buildcraft-compatible wrench to turn on auto-eject mode.