Jump to content

Making the most economical use of a reverse osmosis water filter system?


Recommended Posts

Hi all.  I have a nice RO water filter system under my sink at home that I would like to move into my new ClassA motorhome.  For those who are unfamliar with how RO systems work, heres a brief intro.  The reverse osmosis filter(membrane) filters nearly all minerals and chemicals out of the water - but while doing so it has a self-cleaning mechanism that uses additional unfiltered water to clean itself.  So due to this self-cleaning, for a gallon of filtered water the system wastes about 2-3 gallons of unfiltered water to keep the membrane clean and it is sent down the drain.  

 my sink at home that I would like to move into my new RV.  For those who are unfamliar with how RO systems work, heres a brief intro.  The reverse osmosis filter(membrane) filters nearly all minerals and chemicals out of the water - but while doing so it has a self-cleaning mechanism that uses additional unfiltered water to clean itself.  So due to this self-cleaning, for a gallon of filtered water the system wastes about 2-3 gallons of unfiltered water to keep the membrane clean and it is sent down the drain.  

Now in an RV, I would prefer not to just dump that water on to the ground or worse, fill up my grey water tank with it.  It should be perfectly fine water for washing hands, showers, flushing toilets - so I would like to pipe it back into my clear water tank.  Any ideas how best to accomplish this?   Will I need to drill a new hole somewhere in the clear water tankor are there existing openings I might be able to utilize?  Im as much of a newb as you can be in the world of RVing.  Any advice or insight would be much appreciated.  Thanks!

Link to comment
Share on other sites

You do not want to pipe that "rinsed" water back into your fresh water tank.  It will be full of minerals and other sediment that could eventually cause issues in your fresh water system.  You could come up with a small storage solution under the sink to capture that water so it could be used for washing dishes and flushing toilets, etc., but based on space limitations that might get a bit cumbersome.  Piping that rinsed water to another location where a larger tank could sit might work a little better.

Link to comment
Share on other sites

We've been running a RO system in our trailer for years and I run it on the ground or into the gray tank when hooked to full hookups. After your under counter tank is full it really doesn't use that much water so trying to reroute it is a waste of time.

Denny

Link to comment
Share on other sites

On 4/29/2021 at 5:54 PM, Chad Heiser said:

You do not want to pipe that "rinsed" water back into your fresh water tank.  It will be full of minerals and other sediment that could eventually cause issues in your fresh water system. 

I've been piping my RO "waste" water (aka brine) back into my fresh water tank since I installed the system. Remember, this "waste" water has already gone through a sediment and 1 or 2 other filters before entering the RO membrane. 

RO brine will be saltier, but should have a lower TDS (Total Dissolved Solid) level than the incoming water. For example, these are the TDS levels I found at a campground:

Incoming "fresh" water = 242 ppm
RO water = 30 ppm
Brine = 202 ppm

Link to comment
Share on other sites

If you are piping your RO waste water back into the fresh water tank, you have accomplished nothing except for a waste of electricity.  RO systems generate a lot of waste water which contains the minerals and other contaminates the system is designed to remove.

Link to comment
Share on other sites

2 hours ago, JimK said:

If you are piping your RO waste water back into the fresh water tank, you have accomplished nothing except for a waste of electricity.  RO systems generate a lot of waste water which contains the minerals and other contaminates the system is designed to remove.

For an under sink RO system, it does make sense to pipe the brine water back to the fresh water tank.  Most of your fresh water tank is used for cleaning, not drinking, so if it is a bit brinier, that is OK.

Link to comment
Share on other sites

I've always considered reverse osmosis a very wastefull process in itself of a valuable but limited resource when other means are available.  Using 2-3 gallons to make (1) useable gal ?

Link to comment
Share on other sites

10 hours ago, jc2 said:

I've always considered reverse osmosis a very wastefull process in itself of a valuable but limited resource when other means are available.  Using 2-3 gallons to make (1) useable gal ?

Um, you missed the point. Sending RO brine back into a RV's water tank means ZERO waste.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...