Flushing with grey water

"I heard that some Keystone FWs did plumb the bathroom sink to drain into the black tank..."

Our Forest River MB Cruiser has this "feature" as well. I figured it out the hard way after the bathroom sink was left running. You can imagine what happened when I went to flush...

I've learned to live with that "feature" now, and actually try to make use of it. If I need to dump, but there's not quite enough water in the black tank, it's pretty clean and easy for me to add water to it. It beats standing there with my foot on the pedal.

Id suggest pouring few drops of Clorox into grey tank and it will kill any smell and or bacteria,guaranteed,
I use this in Portapotty and its way more effective then any RV deodorant!

now for some serious water saving someone should import and sell this sink/toilet

http://youtu.be/dB31Es7Z-iU

I have a Swan Industries tank sprayer on my Rexhall.....and it has worked great for twelve years now....another good idea from Bill Rex on his motorhomes.....At the end of dumping, I attach a designated hose just for this to the inlet on the flusher (grey and black switch levers) and flush for a few minutes with the dump valve open....no stink, no build-up. The website for Swan is operable.....try it....

Good Luck.....

I made the modification to flush with grey water and it works GREAT! But I didn't do it quite as planned. The DW and I went to the RV show and you know what can happen when you do. So I negotiated with the dealer to upgrade the new 5er with the mods I had on the old 5er and to also add the grey water flush system. He did a great job and also decided to make the same mod to his personal 5er.

We just came back from a 6-day camping trip where we started flushing with grey water on day 2. There was no smell, the bowl continued to look as good as a bowl can look, and my tanks balanced out very nicely.

I have two grey tanks and only use the bath water.The tank was tapped low to avoid scum and hair and a screen filter was added just before the pump.

I add my black tank chemicals to the grey tank and they are "automatically" dispensed in the black tank as needed, although I did give the black tank an initial dose.

I tested the system, trying in all the known ways to pump grey water back into the fresh water system. The check valves and tee valve did their jobs.

80psi wrote:
I use my macerator pump to pump gray into black through the black water flush inlet.
This allows black tank flush with gray.
This allows gray water transfer for gray water capacity to be extended.

This sounds like a great idea. When you say, "the black water flush inlet." Are you talking about the tank sprayer? If so, I was wondering if that would be too much back pressure on the mancerator pump. I am thinking that the sprayer has a small opening on the inside.

Does it take a long time to transfer the water?

Does the mancerator pump sound normal when pumping?

I am very interested in doing this.

WandaLust2 wrote:
I personally wouldn't want funky greasy soapy gray water sitting my toilet bowl between flushes. We only have two waste tanks so can't draw bath water which can also get smelly what with soaps, hair, body oils and skin cells decomposing in it. No thanks. What a mess that would make the bowl to clean each day and gross to see and smell every time the toilet was used.

Forget the toilet bowl, what about the toilet itself or the spray nozzle. If one adds a bypass on the toilet's water line to use gray water then one has water with substances suspended in it that may very well settle out and coat the water channels under the rim of the toilet and/or the spray's water hose and nozzle. Reminds me of cholesterol plaque building up over time in one's arteries. One could end up servicing or replacing the toilet and/or spray in the future.

Now if one is using a separate spray that is served only by the gray water then one only has to deal with the second spray when it gets gunked up over time. Shut off the water to the toilet, turn on the gray water to the gray spray and service the gray spray when it gets clogged.

I use my macerator pump to pump gray into black through the black water flush inlet.
This allows black tank flush with gray.
This allows gray water transfer for gray water capacity to be extended.

Thanks again everyone-I'm getting some great ideas from your thoughts.

I heard that some Keystone FWs did plumb the bathroom sink to drain into the black tank, and did not mention that "feature" to the owners, which caused a few people to scratch their heads trying to figure out what was going on. But one could also see Keystone's thinking in that the black tank should have plenty of water to keep the solids in suspension. But that approach didn't actually flush the toliet with grey water, instead you still need a fresh water flush.

How would I tap the grey water tank? I like Old-Biscuit's thoughts on transferring liquids between tanks. Again, I don't want to simply dump grey water into the black tank, rather I want to also save some fresh water by flushing grey water into the black tank. So if I installed a drain valve on drain line close to end cap and tapped in just before the new drain valve-I could simply pick which grey tank I want to use for flushing-just DON'T PULL THE BLACK TANK VALVE.

I'll probably wait until spring to begin this project but I'll post my progress and give my analysis of this mod. And your thoughts are always welcome.

Two thoughts off-hand - I may have missed where you included in but if you didn't already, you may want to include some basic filtration between the grey water tank and the pump to make cleaning out the hair and soap scum easier than having to pull the pump screen.

Second, if I were doing it, I'd try to find some way to disable the grey water pump when the three way valve is set to fresh water. Either a physical interlock of some sort or an electrical lockout where that pump could not be powered up until the valve was set to grey water.

Other than those thoughts, it sounds to me like it should do what you are trying to accomplish. As a pre-construction test, I'd go draw a bucket of couple day old bath water from the grey water tank, bring it inside for a few hours, and let DW give it a good sniff to see if the odor is going to be an issue.

I_take_the_5th wrote:
I would like to make a plumbing modification to allow the flush toliet to use grey bath water rather then fresh water. I'm thinking that with a Shurflo pump, a three-way valve, and a check valve (to prevent fresh water contamination) I could extend the use of both my fresh water tank and grey water tanks. Has anyone tried this modification? How has it worked out?

I personally wouldn't want funky greasy soapy gray water sitting my toilet bowl between flushes. We only have two waste tanks so can't draw bath water which can also get smelly what with soaps, hair, body oils and skin cells decomposing in it. No thanks. What a mess that would make the bowl to clean each day and gross to see and smell every time the toilet was used.