DIY Grey and Black Water Tanks? How do I plumb it?

[Scott]

Hey Guys,

Haven't posted lately as I've started a new job and have been super busy. Right now I'm just working as much overtime as I can and saving up to do my build. One of the last major areas I need to learn about and get a handle on is how I want to do my plumbing. I am in between building a full class B conversion (toilet and shower) which will need a black water tank. Or just plumbing for a grey water tank. Besides the detrimental ecological effects of just dumping gray water straight onto the ground, I plan to stealth camp in areas were I can't just run a pipe straight out of the van. So, has anyone plumbed their own grey/black water tanks? I'm trying to get a feel for how the best way of going about it will be. I will probably consult with a friend of mine who's been a contractor and handyman for years, but I figured if someones done it, they'll be here. I at least need a grey tank. I think part of my hesitance for putting in a toilet and shower is just lack of knowledge of how I would do it myself properly (and space). My google-fu is normally pretty strong, but I've been having trouble finding this information. What type of setup is needed to install your own grey tank?

Thanks,
Scott

 

[highdesertranger]

here is a simple schematic. http://www.marxrv.com/plumbing/plumb.htm . notice all except the toilet goes to grey. hope this helps. highdesertranger

 

[gadgetMe]

grey and black water tanks are separate units, so each has it's own drain (water going in) and drain valve.
Most drain or dump plumbing sizes are a minimum of 3 inches in diameter.
Sewer pvc is good for the plumbing (no need for schedule 40 pipe) almost all dump valves are the blade type
also check out RV supply places for the "bayonet" connection for the waste hose hookup
The grey water will fill much faster than the black water, may want to consider that in sizing of the tanks

Gadget

 

[christine]

Installing a grey water tank can actually be very simple. All you need is a hose or a pipe going from the sink drain down to the tank. You can get the tank and fittings at Plastic Mart. If you want to get fancy and make sure that smells from the grey tank don't come back up into the van, you can install a P-trap. I used water heater strapping to secure my grey water tank to the underside of my van. It's worked great so far, hasn't loosened at all.

 

[Almost There]

The P-trap is useful for another thing as well as keeping the smell out of the living area. When you have no p-trap anything including cutlery can go straight (or not so straight depending on the line) down into the tank, never to be seen again!

 

[highdesertranger]

hummm, how do you know that Almost There? highdesertranger

 

[Almost There]

hummm,  how do you know that Almost There?  highdesertranger

Let's just say that a trap has saved various things from extinction over the years....

 

[ccbreder]

with no toilet, you only need a grey water tank. With a toilet you also need a black water tank. You can use the black water tank for both.

 

[LeeRevell]

Don't forget the tank venting.....

 

[GotSmart]

Let's just say that a trap has saved various things from extinction over the years....

Some would be more stinky than others!

I had a plumbing customer that would lose her ring down the drain about once a week.  I replaced her trap with one that had a removable plug on the bottom.  

http://www.homedepot.com/p/NIBCO-2-in-PVC-DWV-Hub-x-Hub-x-Cleanout-P-Trap-C4884HD2/100343824

 

[BradKW]

I found the marxrv link to contain some very helpful information.

What I'm finding a bit intimidating about figuring how to plumb a Sprinter isn't really the "how to" of plumbing, as I enough experience with pvc and peks to feel comfortable making connections and such. What I'd really like to see is examples of holding tanks, what they are, and how/where they are mounted. Is where I place a marine toilet determined by where I can fit a tank below? How do you put a P-trap under a shower...does it just hang out under the vehicle?

Also, how much of an issue can finding somewhere to dump be? Do campgrounds usually offer use of dumping facility for a fee to people who aren't staying there?

Thanks for any input! 

 

[highdesertranger]

do you have a link to the toilet? in RV's the black tank mounts directly under the toilet, there is no tap in a RV toilet it relies un an air tight seal to keep odors out. as far as the grey system goes, yes a regular p traps will work. they also make a special trap for RV here is one type http://www.rvpartscountry.com/camper-drain.html . here is another http://www.drainmaster.com/main/201...your-rv-hepvo-waterless-p-trap-to-the-rescue/ it's down towards the bottom of the page. a note on the conventional p-traps after traveling for the day in your RV it's a good idea to run a little water down the drain to make sure your p-trap is full. any more questions feel free to ask. highdesertranger

 

[compassrose]

Is where I place a marine toilet determined by where I can fit a tank below?

For a VERY short run (like the length of the fitting) you can plumb a marine/RV toilet at the edge of the tank with a 45 degree. According to code (yes, there is a building code for recreational vehicles) all inlet plumbing fittings (the toilet drain) is to be on the top of the black tank. I would not risk a 90 degree turn, not even a sweep.

How do you put a P-trap under a shower...does it just hang out under the vehicle?

my shower pan sits on the floor of the bus. The p-trap is under the bus where the fresh & grey holding tanks are located.

Also, how much of an issue can finding somewhere to dump be?

www.sanidumps.com is a free listing. Many public campgrounds have a dump station, especially if they do not have full hookups. I can't say most because some one will object because they know of a campground that does not have a dump station. So I will say many. Many private campgrounds have dump stations as well. I have noticed that this seems to be getting fewer since so many abuse the setup.

Do campgrounds usually offer use of dumping facility for a fee to people who aren't staying there?

The parks that have a dump station will charge you to dump. Anywhere from $2 to $25. You can also get fresh water.

 

[ahh_me2]

a note on the conventional p-traps after traveling for the day in your RV it's a good idea to run a little water down the drain to make sure your p-trap is full. highdesertranger

Good point! I'm not sure I would have thought of that! The water will have a tendency to slosh itself out of the trap rendering it ineffective!

 

[ZoNiE]

Consider a cassette toilet. They have their own little black tank that you pull a lever, remove, and go dump in a toilet. All the RV's in Europe have them as do many popup trailers here.

Otherwise, with limited space under a van, consider a single black tank for everything. Many truck campers and old Motorhomes had this.

here are some sources for materials:

Plastic mart

Ameri-kart

Cassette Toilet - Spendy

If you go black tank route, put the tank right under the toilet so it dumps right into it. NO piping or bends, You will never keep it clean...

 

[B and C]

You will also need a vent pipe(s) from the tank(s) to the roof if installing permanent holding tanks.  You could always go to a RV dealer and check how it is done.

 

[Canine]

When re-modeling the Gray Goose I had no room under the shower for a trap.I went to Lowes ang picked up a plumbing test plug.We leave the plug in all the time except when showering.

 

[BradKW]

This looks like a pretty slick solution...probably saves at least 4" ?

 

[highdesertranger]

Brad that's like the one I linked to. remember though just like with regular trap you must have access to it to clear plug ups. a big problem with those diaphragm ones is hair gets caught in the diaphragm and it won't seal, then the odors get by. highdesertranger