Use gray to flush black

[theoldwizard1]

Related to my previous post, has anyone tried some kind of pump to use their gray water to flush a toilet ?

[Almot]

mockturtle wrote:
I think some of you guys are just bored. :R 😉

x2.
Emptying dish water in toilet is simple and efficient.
For a while I kept my kitchen sink drain open, collecting water in a small bucket and then emptying on surrounding shrubs, they appreciate it on a hot day. Slight complication was that I couldn't see when the bucket was full until I open the sink cabinet, so I stopped doing it.

[Lazy_D]

BarneyS wrote:

Vintage465 wrote:
Before I got a trailer with a Sani-flush, I would drain the black tank first...leave the black tank valve open....Then......Carefully remove the end of the hose from the dump station hole and hold the hose up in the air, higher then the tank and reach down and open the grey valve. The grey water would run into the black tank 'til it equalized...tricky part was shutting both valves while you continue to hold the hose up. And there would be a little "mixed" waste water in the hose while you got it back to the dump station hole. I suppose you could install a third valve to manage that though.

Just get a Valterra Twist On Gate Valve and put it on the end of the drain pipe just in front of the slinky. That way, you can close the valve, open both grey and black valves, and the liquid will equalize without going down the slinky. When done, close one of the tank valves, open the Valterra and drain as usual.

It looks similar to this one but without the clear plastic elbow.
Barney

I always thought to myself why don’t they plumb the gray tanks to flush through the black tank to help clean it out. Then a while back I bought the twist on valve. OMG it works like a champ! I still use the sani-flush to keep clear water flowing into the black, but this is the way to go.

[TakingThe5th]

theoldwizard1 wrote:

TakingThe5th wrote:

I have a grey water flushing system installed in my 5th.
.
.
.
I have a separate pump and filter for the grey side.

Anything "special" about the pump and filter you are using ? Could you share the brand and model numbers ?

The pump is an Artis Model PDS1RV25, 40 psi max, draws 7.0 amps on 12 volts.
There was no visible information on the filter but it is shown below

Here is the pump and filter. The water flow is up and over. The lower pipe taps into the grey water tank about one quarter up from the bottom. There is also a low point drain on the lower pipe which is needed for winterizing -

Click For Full-Size Image.

Here is a close shot of the filter. You can see the screen -

Click For Full-Size Image.

Here are the valves used to select fresh or grey water for flushing. Grey feed is on the right, fresh feed is on the left. The blue pipes are the original fresh water supply. The valve on the right selects the water source. The valve on the left, along with the check valves, is used to insure that no grey water enters the fresh water system. Right now the valves are set for fresh water use -

Click For Full-Size Image.

And finally, this switch powers the demand pump and is in the bathroom. Normally left on, but if the pump starts grinding in the middle of the night we can quickly stop the noise and save the pump. Originally I wanted to mount all the valves in the bathroom next to the toilet, but there was not enough room. -

Click For Full-Size Image.

Hope this helps. Good luck -

[TakingThe5th]

Bobbo wrote:
Gray water stinks as bad as black water. I wouldn't want that in my toilet after you flush.

Grey water that includes kitchen waste does smell bad, but if you have two grey tanks the bathroom water is good quality and stays that way with the use of black tank chemicals and active use.

[mikestock]

BarneyS wrote:

Vintage465 wrote:
Before I got a trailer with a Sani-flush, I would drain the black tank first...leave the black tank valve open....Then......Carefully remove the end of the hose from the dump station hole and hold the hose up in the air, higher then the tank and reach down and open the grey valve. The grey water would run into the black tank 'til it equalized...tricky part was shutting both valves while you continue to hold the hose up. And there would be a little "mixed" waste water in the hose while you got it back to the dump station hole. I suppose you could install a third valve to manage that though.

Just get a Valterra Twist On Gate Valve and put it on the end of the drain pipe just in front of the slinky. That way, you can close the valve, open both grey and black valves, and the liquid will equalize without going down the slinky. When done, close one of the tank valves, open the Valterra and drain as usual.

It looks similar to this one but without the clear plastic elbow.
Barney

I like the method that Vintage465 uses. I do the same except I can twist my outlet manifold upward to stop the flow through the hose. Just a quick way to do a little extra wash of the black tank. The more gray water you have the better it works.

[mockturtle]

I think some of you guys are just bored. :R 😉

[mikestock]

I have a clear section of sewer pipe and the first glug of gray water is pretty nasty with solids and coffee grounds.

After having trouble with my air admittance valve, changing it out, I still got a smell from my washer closet. We now, meticulously, clean all partulates before washing dishes. It's a little trouble, but got rid of the smell.

[BarneyS]

Vintage465 wrote:
Before I got a trailer with a Sani-flush, I would drain the black tank first...leave the black tank valve open....Then......Carefully remove the end of the hose from the dump station hole and hold the hose up in the air, higher then the tank and reach down and open the grey valve. The grey water would run into the black tank 'til it equalized...tricky part was shutting both valves while you continue to hold the hose up. And there would be a little "mixed" waste water in the hose while you got it back to the dump station hole. I suppose you could install a third valve to manage that though.

Just get a Valterra Twist On Gate Valve and put it on the end of the drain pipe just in front of the slinky. That way, you can close the valve, open both grey and black valves, and the liquid will equalize without going down the slinky. When done, close one of the tank valves, open the Valterra and drain as usual.

It looks similar to this one but without the clear plastic elbow.
Barney

[valhalla360]

Gray water often smells worse than black.

No thanks.

[Vintage465]

Before I got a trailer with a Sani-flush, I would drain the black tank first...leave the black tank valve open....Then......Carefully remove the end of the hose from the dump station hole and hold the hose up in the air, higher then the tank and reach down and open the grey valve. The grey water would run into the black tank 'til it equalized...tricky part was shutting both valves while you continue to hold the hose up. And there would be a little "mixed" waste water in the hose while you got it back to the dump station hole. I suppose you could install a third valve to manage that though.

[Bobbo]

Gray water stinks as bad as black water. I wouldn't want that in my toilet after you flush.

[TakingThe5th]

theoldwizard1 wrote:

TakingThe5th wrote:

I have a grey water flushing system installed in my 5th.
.
.
.
I have a separate pump and filter for the grey side.

Anything "special" about the pump and filter you are using ? Could you share the brand and model numbers ?

The filter I use is a "bowl" filter with an element that is more like a screen then a filter which is good for catching hair and can be cleaned. The pump you will use should almost be equivalent to your own fresh water demand pump but make sure it cannot out-pump the freshwater pump. I have check valves in my system but in any event I do not want the grey water pump to be able to overpower the fresh water pump head to head, just as a further safety precaution. Like the fresh water pump, the grey water pump should be a demand pump.

I can look for model numbers for you tomorrow.

[theoldwizard1]

TakingThe5th wrote:

I have a grey water flushing system installed in my 5th.
.
.
.
I have a separate pump and filter for the grey side.

Anything "special" about the pump and filter you are using ? Could you share the brand and model numbers ?

[TakingThe5th]

DrewE wrote:
The question wasn't about using gray water to flush out the black tank, but using it to flush the toilet. I think I've read here of one or two people who have rigged something up to do that. It's basically just installing a suitable pump and running some water lines to it. Probably having a selector valve to let either the fresh or gray water be used for flushing (and a check valve for the fresh water line to prevent any possible cross-contamination from the gray water) would be a decent idea in case one needs to go potty before anyone has taken a shower or washed the dishes.

Note that the gray water can get pretty stinky over time. For the amount of fresh water that would be saved, I don't think I would bother. RV toilets don't need a lot of water to flush.

I have a grey water flushing system installed in my 5th. I have two grey water tanks and I only flush using the shower and bathroom sink water so the water is pretty clean. I can select fresh or gray water for flushing. I have a separate pump and filter for the grey side. Our problem was that the grey shower water tank would fill up 1st while the fresh water tank would become empty 1st. The grey water system creates a perfect tank balance and we are not afraid to use adequate amounts of water for flushing. I use black tank chemicals but put them into the grey tank where they get dispensed over time into the black tank. The system works well and extends our stay by several days.