John Reich Posted April 29, 2021 Report Share Posted April 29, 2021 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! Quote Link to comment Share on other sites More sharing options...
Chad Heiser Posted April 30, 2021 Report Share Posted April 30, 2021 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. Quote 2009 Volvo 670 with dinette/workstation sleeper - Walter 2017 DRV Mobile Suite 40KSSB4 with factory mods, dealer mods and personal mods - now in the RV graveyard 2022 DRV Full House MX450 with customized floor plan 2018 Polaris RZR Turbo S (fits in the garage) 2016 Smart Car (fits in the garage or gets flat towed behind the DRV when the RZR is in the garage) My First Solar Install Thread My Second Solar Install Thread & Photos and Documents Related to the build My MX450's solar, battery and inverter system - my biggest system yet! chadheiser.com West Coast HDT Rally Website Link to comment Share on other sites More sharing options...
D&J Posted April 30, 2021 Report Share Posted April 30, 2021 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 Quote Denny & Jami SKP#90175 Most Timing with Mac our Scottie, RIP Jasper our Westie 2013 F350 SC DRW 6.2 V8 4.30 Gears 2003 HH Premier 35FKTG Home Base Nebraska Link to comment Share on other sites More sharing options...
Zulu Posted May 1, 2021 Report Share Posted May 1, 2021 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 Quote SKP #79313 / Full-Timing / 2001 National RV Sea View / 2008 Jeep Wrangler Rubiconwww.rvSeniorMoments.comDISH TV for RVs Link to comment Share on other sites More sharing options...
JimK Posted May 2, 2021 Report Share Posted May 2, 2021 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. Quote Link to comment Share on other sites More sharing options...
Bill Joyce Posted May 2, 2021 Report Share Posted May 2, 2021 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. Quote 2004 40' Newmar Dutch Star DP towing an AWD 2020 Ford Escape Hybrid, Fulltimer July 2003 to October 2018, Parttimer now. Travels through much of 2013 - http://www.sacnoth.com - Bill, Diane and Evita (the cat) Link to comment Share on other sites More sharing options...
jc2 Posted May 2, 2021 Report Share Posted May 2, 2021 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 ? Quote 2010 Newmar Dutch Aire 4304-Spartan Chassis-Cummins ISL 425hp-2013 Chevrolet Equinox AWD Towed-SKP# 120487-FMCA #402879- Link to comment Share on other sites More sharing options...
Zulu Posted May 3, 2021 Report Share Posted May 3, 2021 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. Quote SKP #79313 / Full-Timing / 2001 National RV Sea View / 2008 Jeep Wrangler Rubiconwww.rvSeniorMoments.comDISH TV for RVs Link to comment Share on other sites More sharing options...
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