They must be getting water (dirty or otherwise) from somewhere or they'd already be dead. I fail to see how mixing that water with Soylent leaves them worse off

They must be getting water (dirty or otherwise) from somewhere or they'd already be dead. I fail to see how mixing that water with Soylent leaves them worse off. Furthermore, there's no reason Soylent can't be baked into a solid form and distributed/eaten that way.