On-demand RO?


Prolific Poster
May 9, 2009
So, I've got a 50gpd RO system plumbed in my basement. It feeds the icemaker, drinking water faucet and a spigot behind my aquarium.

Problem is, a PWC on my tank takes a day and a half to refill using the RO...even if it runs non-stop...and I can't let it run non-stop or my wife can't make her coffee in the even and morning.

What I would like to do is have a resevoir of RO water that is around 50 gallons, so I can do PWCs with impunity.

Catch is, I'm broke. :D

How to accomplish this on the cheap?

My first thought was a largish bladder tank, but that turns out to be cost prohibitive.

OK, so how about an improvised atmospheric tank made of a Brute trash barrel? Cost is right. But how do I control it? I've got no issue putting a level control on the barrel to keep it full, but how do I provide pressurized water from it to the various outlets on the floor above?

Adding a pump and small bladder is going to be just as expensive as adding a single large bladder, so that's out.

Is the bladder even necessary? Perhaps a small jet pump or transfer pump, check valve, and a pressure switch set to around 20 psi?

Are typical (cheap) pumps going to be OK with RO water (I'm guessing not)?



Guru Class Expert
Jun 15, 2009
if you want it on the cheap, stick with a 50gallon container of some sort, a float switch to control level and a good centrifugal pump (the costly bit, try a shower booster pump from ebay) :)