Ok, this idea will make no sense to those who have not gone RV camping. RVs have 3 water tanks — one for fresh water, one for the toilet sewage (known as “black water”) and one for the other drains (shower, sinks) known as “grey water.” When you camp in unserviced campsites for a while you become very aware of the capacities of your tanks.
However, the RV uses the fresh water tank to “flush” the toilet. It seems to me that with a small extra water pump, one could use the grey water, or a mixture — grey with a final spurt of fresh to rinse the bowl.
RVs don’t really flush the toilet, that would use way too much water. You rinse the bowl after #1 and you pre-fill the bowl before #2 and rinse later.
Yes this requires an extra pump, and since you can’t draw from the very bottom of the grey tank, which has some sludge, you even need access to both pumps which perhaps makes this too complex, and thus explains why it isn’t done. And the surplus of “free” water might make you overfill the black tank, which is sometimes your limiting tank. And perhaps if you are going this far you should make the jump to a propane powered composting toilet.
Composting Toilets
I am interested in comments (pro or con) from people who own stand alone composting toilets.
I am NOT interested in testimonials from the manufacturers.
Dear Brad,
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grey water flushing
I use grey water exculesively to flush my rv toiet on long, remote trips. I installed a side input into my grey water tank 1/2" above the bottom of the tank towards the rear of the tank w/ a simple water filter followed by a demand pump in the line. When setting up, I simply make sure my rv is sloped one degree or so downward toward the rear. I have a valve, just under the edge of the trailer which branches to the grey or fresh water feed. When valved to fresh water, the extra pump is unnessary. (So that if you have full hookups or are on a short weekend trip it is unnecessary to tap the grey...The systems works great, you just learn very quickly not to pour things like coffee, soda, etc down the sink. They have a tendacy to return to the toliet rather stinky (the key is too limit sugars and protiens). Do that, with the filter, you wont know the difference.. After using this system quite extensively on my rural property, it is very easy to go a couple weeks without dumping. (using the outside shower...) I have a gravity feed spring, so fresh water is not an issue, only dumping...
water recycling
has anyone heard of a commercial system that will recycle/filter the grey water for you? do any r.v.s come with this technology? thanks!
I was just wondering about
I was just wondering about this today which was what led me to this page. In many areas, Car Wash's and Laundromats are required to recycle their water, so I would imagine that some system could be devised on a smaller scale that could be installed in a motorhome or trailer. The task of flushing and refilling your water tanks is a real pain and the ability to recycle your gray water would extend the maintenance interval on your tanks considerably as many water uses could be done from your gray tank rather than your fresh tank. I wouldn't drink or cook with water from the gray tank, of course, but for toilet and wash down purposes it would save a lot of water and maintenance over time.
grey water
Will be setting up a camp at the lake and will not have water or sewer. The chem toilet or portapottie will work and have to be dumped or a portajohn service used. The problem will be showers and the grey water and what we can do there. Any suggestions? The lake assoc. and town are very strict. Please email with your ideas. WE are used to camping with an RV and Sewer system.
Great idea!
We're planning on buying a small RV soon and I didn't realize until reading your blog post that RV's don't use the grey water for flushing.
It makes so much more sense. When we finally get our RV I'll be making this modification.
Thanks for the inspiration.
Gray water and RVs
I have been reading about graywater recycling systems for homes, and am thinking about a scaled down version for an RV, as a way to safely dispose of graywater without a dump. I find I'm often in a position to get water but dump stations are much more rare. Some ideas:
> Wash the RV with the graywater (using biodegradable soap would be a nice idea on this one)
> Filter the graywater with a sediment filter to catch hair, food particles, etc. then use a mini soil leachfield (perhaps a large potted plant or two) to filter the water then pass it out the bottom on to the ground or storm drain, or use it to water any nearby plant life)
> Boil it, distill it, treat it--then you can reuse it over and over for washing (the RV), flushing, etc. whatever you feel comfortable with. But you'd need a 4th tank for "white" water... treated gray water to be used for certain things.
I'm wondering how I can test white water to see if it's clean enough to legally use in a way that discharges it on the ground, i.e. washing a vehicle, watering plants, etc.
ideas and thoughts on any of this?
- B
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