[pairodice]

Thanks Richard but couldn't you recycle the water back through to the main filters? They do it on the space station... Lol

[Richard]

Of course you can recycle the water bank to the tank. But the rejected water from the RO system is higher in mineral content than the water fed to the drinking water tank. So now you are feeding high mineral water into the holdling tank. Of course you are diluting that water with fresh water each time you refill. So an algebraic expression could be crafted to calculate how high the mineral content of the tank water would rise if one knew how much water was used for other than drinking, the mineral content of the incoming water, and the ratio of drinking water to other water use.

I was just trying to make the point that the reject water has a higher mineral content, and you would be raising the mineral content of the water in the holding tank. Kind of counterproductive when what you are trying to do is reduce the mineral content of the water.

[pairodice]

"So an algebraic expression could be crafted to calculate how high the mineral content of the tank water would rise if one knew how much water was used for other than drinking"
You're just trying to make my head hurt aren't you?  lol  
Where does this 'waste water' go?  How much is produced?  Would an RO system not work for boon docking because of this?  
Thanks for the input, I do appreciate it!

[encantotom]

waste water goes into the sewer tank. same as with RO at home. it goes down the sewer.

most RO system makers claim 4 gallons of waste water to 1 gallon of RO water.

that is why the RO is only hooked up usually to a separate faucet on the sink and the fridge.

so it depends on how much ice and how much water you drink out of the separate RO faucet.

at home we probably do 1 to 2 gallons a day

tom