How Much Water

[KevinCoughlin]

Just a note no letting gray water dump out on the ground. Some jurisdictions get cranky about a drain hose, but find tossing a bucket of water perfectly fine. In my current bus I have a 5 gallon water jug and a hand pump thing (like the air pump coffee dispensers) that is next to and over the sink. The sink drains straight into a 5 gallon bucket. I can never over fill the bucket, since both my source and endpoint are equal. As for dumping the washwater, I just carry the bucket over to a handy bush and give it a toss (no mud under the bus for the dogs to get in, either).

That being said.... for the bus I'm building this summer I'm going with BIG tanks. I'm actually raising the floor almost a foot (to give me a flat floor over the wheel wells, plus room for a wiring run and insulation and heat ducting) and the roof almost twice that amount.... This will leave me room for some tanks sandwiched between the original bus floor and the new floor where they hopefully won't freeze.

[Elliot Naess]

Hi! I was a FNG here not too long ago, and now I'm a FOG. Doesn't seem to be much of a difference.

What you are probably thinking of, is that most commercially built camping vehicles have the two tank outlets connected into one drain outlet in such a way that you can flush the drain outlet flange, and the hose, with the gray water after you have dumped the black. That's simply the standard way of doing this.

I suppose you could arrange a black-tank-flushing-system with your gray water, but I'm not up on that. What I do know, is that some of the "real" campers have a "sprinkler" system in the black tank for flushing it -- I just don't know if they use gray or fresh water for that.

At the less expensive end of the spectrum, you can buy -- or make yourself -- a spray wand that you stick down the toilet and swish water around to rinse out the tank.

[KevinCoughlin]

The other bit for having some way of stuffing the grey water into the black is to give it a good bit of pressure. When you have a partially filled black tank (for example - you only put 25 gallons into your giant 100 gallon black tank) and go to the dump station, you might have some issues making sure that when you pull the valve handle it goes "whoosh" out into the dumper. If you kick 50 more gallons of grey water into the black tank first.... you have that much more ready and waiting and primed by gravity to give it a good push - and not clogging in the hose or valve body.

Commercial RV systems say that it should never be smaller than 3" openings on the way out. Big valves, big pipes, and no really fancy tight corners, so that when it is time, it really DOES "all flow downhill".

Then, after the first dump, you can rinse the potty tank with the wand through the toilet itself (and of course, you have a separate hose for that which is never used for filling your potable tanks, right?). Whatever is left of the grey is then dumped as well, clearing out the valves and lines.

In the next bus I'm leaning towards a pair or 40 gallon potable source tanks (already have them), one HUGE custom built black/grey tank (120 - 150 gallons), and a tap before the tank that lets me divert the grey water before it goes into the tank if I am at a place where I have the chance to hook up a drain hose. I can "top off" and help rinse the black/grey combo tank by just turning on the shower and letting it run until I fill the tank enough to give it the final dump. I like the idea of "sprinklers" built into the tank - I will have to look into that. If I am building the tank, I might as well add some bells and whistles.

Of course, currently out in the boondocks where I live, I use a thermophilic composting system - look up a "sawdust toilet" or "humanure handbook".... but this only works if you live on your own land, it does not translate well to something mobile, as it requires a properly setup composting bin.

[Anonybus]

Originally Posted by GoneCamping

Having owned a couple of RV's already, and currently building my own I do know a little on this subject. First of all, the black tank does not need to be as big as the gray tank, you'll use a lot more water for gray purposes (dishes, showers, etc) than you ever will down the toilet. Be that as it may, I used a pair of 36 gallone gray & black tanks that I bought HERE for $45 each. My water tank is a bit larger at around 60 gallons.

Now, I will never - ever fill that black tank as such, so I'm going to add a transfer pump so I can pump gray water into the black tank, thus expanding my gray water capacity...and by doing this, I'll add enough water to the black tank that it'll have plenty in there to help flush out the solids when times comes to do the dump....

I'm curious how long your 60 gal fresh water lasts you? Are you solo or do you have someone else along that is using up fresh water too? Trying to decide how big to go in my short bus for full time use. I will have access to frequent fill ups, but I'm trying to balance weight with convenience, ya know?

[Rucker]

After a lot of research I decided to install a 25 gallon freshwater tank and store 3 jerrycans for a total of 40, and 40 gallons for gray. Composting toilet.

Still building the thing, so I can't tell you from real life. Our design goal is 4 days off grid, two people.

[Iceni John]

Originally Posted by KevinCoughlin

The other bit for having some way of stuffing the grey water into the black is to give it a good bit of pressure. When you have a partially filled black tank (for example - you only put 25 gallons into your giant 100 gallon black tank) and go to the dump station, you might have some issues making sure that when you pull the valve handle it goes "whoosh" out into the dumper. If you kick 50 more gallons of grey water into the black tank first.... you have that much more ready and waiting and primed by gravity to give it a good push - and not clogging in the hose or valve body.

Commercial RV systems say that it should never be smaller than 3" openings on the way out. Big valves, big pipes, and no really fancy tight corners, so that when it is time, it really DOES "all flow downhill".

Then, after the first dump, you can rinse the potty tank with the wand through the toilet itself (and of course, you have a separate hose for that which is never used for filling your potable tanks, right?). Whatever is left of the grey is then dumped as well, clearing out the valves and lines.

In the next bus I'm leaning towards a pair or 40 gallon potable source tanks (already have them), one HUGE custom built black/grey tank (120 - 150 gallons), and a tap before the tank that lets me divert the grey water before it goes into the tank if I am at a place where I have the chance to hook up a drain hose. I can "top off" and help rinse the black/grey combo tank by just turning on the shower and letting it run until I fill the tank enough to give it the final dump. I like the idea of "sprinklers" built into the tank - I will have to look into that. If I am building the tank, I might as well add some bells and whistles.

Of course, currently out in the boondocks where I live, I use a thermophilic composting system - look up a "sawdust toilet" or "humanure handbook".... but this only works if you live on your own land, it does not translate well to something mobile, as it requires a properly setup composting bin.

Wow, I've done most of the things you suggest! My 65-gal poo tank is about 24" high, so when it's full it will empty with some authority - no stuck turds for me. And to make it full before dumping, I have a Harbor Fright transfer/utility pump to move grey water into the poo tank, and I can also connect shore water to the poo tank as well, both feeds obviously through check valves; the water inlet in the top of the poo tank is directly above its dump outlet to help break down any Mounds Of Doom that are growing there like malevolent stalagmites.

I have the recommended 2-into-1 dump outlets and a 3rd dump valve to make it easy to flush the stinky slinky with cleanish water from the grey tank. For my 115-gal grey tank I have an alternate 1.5" dump outlet on the kerb-side of the bus just ahead of the right rear wheels, so I could theoretically (and I stress only theoretically...) release excess grey water into a drain or gradually onto the ground, not that I ever would do so... Another way I can prevent filling the grey tank too much is a 1" ball valve on the shower's drain line that will allow shower water to drain straight to the ground or to a hose. Water from the kitchen sink and the washing machine can only go into the grey tank.

With 220 gallons of fresh water I should be able to live comfortably off-grid for at least a month, including doing all the normal things like having a nice shower every night and using the washing machine, and even washing down my solar panels by using the quick-connect water outlets on the roof walkway. Good plumbing design is important if you're fulltiming!

John

[ol trunt]

IJ, that's less than 7.5 gallons a day. No way you'll be able to bathe and do laundry etc. with that volume of water plus the solar wash and general household uses. Check out your home water usage and you'll see what I mean.
Jack

[flattracker]

I have already installed a 40 gallon black tank and will install a 40 gallon fresh water tank in my Crown. My previous experience found that with careful use of water we could go several days with 40 gallons of stored fresh water and matching waste water storage. We don't expect to do long periods of dry camping, but more like stop at RV parks at least twice a week. The fresh water tank will be under the kitchen sink. I plan to mount the tank with restraints strong enough for a full tank of ~ 320 lbs of water. The waste tank is mounted under the floor with mounts strong enough for ~320 lbs of waste water. I placed the drain end of the waste tank forward where it is more accessible to connect the stinky slinky and operate the gate valve. My fresh water fill valve will pass through the floor. When all of the external connections are made (electricity, fresh water, waste water) I can close the hatch and one does not see them. I did the connections like that on the "old Crown" also.

[Iceni John]

Originally Posted by ol trunt

IJ, that's less than 7.5 gallons a day. No way you'll be able to bathe and do laundry etc. with that volume of water plus the solar wash and general household uses. Check out your home water usage and you'll see what I mean.
Jack

Don't worry, I'm not doing laundry or washing the panels every day! I can have a perfectly satisfactory shower with less than 4 gallons (a so-called Navy shower), the Dometic 310 loo uses only a few pints per flush, I cook essentially nothing (that's what microwave ovens are for!), and a load of laundry in the little Splendide washer would be every week or two. Washing the panels is only needed when they get too dusty or bird-poopy, maybe every month or so. Yes, compared to the obscene amount of water that most Americans use in a regular home this does seem miniscule, but most Americans live extravagantly profligate and wasteful lives beset by derisible inefficiency and a scornful lack of concern for minimizing their environmental footprint. Mobile living will be a way to reduce my environmental impact, and if it means that I have to be limited by my bus's finite resources, so be it. Actually I'm looking forward to it! Less is more.

John