Shower drains into black tank

[Gary M]

If you go the composting toilet route you could remove either the black or the gray tank and replace it with a fresh water tank.

I thought about this too. Having 2 fresh water tanks would be awesome, but there would still be the dilemma of having to re-route either the shower or sink drains, and they're both on opposite sides of the trailer.
Because of this, and what Merlin mentioned about composting toilets not being so good for families (vs just 2 people),  I'm starting to lean away from the composting toilet idea. Doesn't seem like it would even be worth it to have 50 gallons of grey(by combining tanks), and only 25 gallons of fresh water

[charliem]

I've always considered FW to be the least problematic. Extra FW is so easy to find and carry in the truck. The real limit has always been gray water storage. BTW I'm also curious about that funny "valve". Does the top unscrew? Is there room to unscrew it if it does?
FWIW the early 21s advertised 28/32/30 gal black/gray/fresh tanks. That was all pre Thor. They tried to "standardize" across the product line, thereby applying the well known principle of lowest common denominator  .

[Gary M]

I've always considered FW to be the least problematic. Extra FW is so easy to find and carry in the truck. The real limit has always been gray water storage. BTW I'm also curious about that funny "valve". Does the top unscrew? Is there room to unscrew it if it does?

Nah there's no room to unscrew it unless i remove the shower pan or bend the heck out of the pvc. I'm just gonna leave the funny valve alone for now.

I really wish my limit was gray water.. In a pinch i would much rather dump a bucket of gray water down the toilet, than a bucket of poop water down the sink! lol 

Anyways, I have some new pics and ideas. posting shortly..

[Gary M]

So I looked under the underbelly, and back up top, and I think I have a pretty good backup plan..

The black tank is 26" wide, and the aft side of it is 1' forward of the back wall. The gray tank is 1' forward of the black tank. It begins at the center of the furnace and is 17" wide. (This is about 1' past the shower wall which is why they couldn't use that vent to the gray tank). Both tanks are roughly 5" deep and are supported by 2 braces that run across the fwd and aft sides of the tanks from port to stbd.

The underbelly heating duct hole is located at about center of the gray tank (going fwd and aft), and its 2" to the left edge side of the gray tank. This would be my landmark for drilling the hole through the floor upstairs.

Both tanks look like theyre in the only spot they would fit because of the trailer frame cross beams. So they either used different tanks or changed the layout of the frame.

My plan if they won't fix it:

I would leave the black tank drain side as is (I'll explain this later), and install a T fitting on the end of the HepvO valve. The gray tank drain side would come off the T heading to the port side wall, and run behind the furnace (4" high x 3 1/4" wide opening under exhaust pipe), and back around towards the front of the furnace. The hole would be just inside the access panel on the right side of the furnace and about 3-4" from the underbelly heat duct hole. I would just need to glue in a flange with a seal into the top of the tank. There would be easy access in this compartment, and I don't think i would even need to remove the furnace, fridge, or underbelly. All i would need to remove is the shower.

Leaving black tank drain connected:

"According to NFPA 1192, Paragraph 7.4.2.4, horizontal runs of waste piping should slant towards the holding tank no less than 1/8-inch per linear foot. Additionally, the waste piping should be supported not less than every four feet. If allowed to sag, belly-down or slope upwards, waste water can be trapped inside the drain system and become a breeding ground for bacteria growth as well as odors."

My gray tank run would be less than 3' in total, meaning my slope only needs to be a drop of 3/8" from start to finish to be in RV specs. If I make it a little lower than the black tank drain pipes, then theoretically.. water should fill the gray tank first, and once its full, it should automatically start draining into the black tank! genius right? I think I could accept this as a consolation prize for having to deal with all this! haha

I almost want to avoid anyone else doing the work, just so i can set this dual drain up myself.

So far the only challenge I see is heat from the back of the furnace with the PVC being so close. I was thinking I could maybe install a metal heat shield or use a different kind of piping for that short section. If you guys have any ideas or see other holes in my plan, please let me know

[Merlin]

It's not possible to visualize the elevations without being there, but it sounds good! You won't get a better solution from LL and if the camper is built as designed, they won't do anything anyway. In your planning, just be sure the toilet can't drain, even a little bit, into the new grey tank plumbing. Also, your plan may result in the grey tank vent up top also being open to the black tank, so make sure you won't have an odor problem near the grey tank vent. Using the black tank as "overflow" for the grey tank is pretty cool; don't forget to patent that idea 

I hope others will chime in here with kudos or pitfalls or both.

If you make a simple pipe chase out of aluminum sheet metal for the PVC pipe as it goes by the furnace, it seems like that would be ok heat shield. Just be sure you don't restrict air flow in/around the furnace.

[charliem]

Check the tank material before you decide how to install the new entry. The OEM fittings are usually welded in by spinning them to heat by friction. If the tanks are polyethylene no adhesive will stick. Somewhere I saw a compression/expansion fitting that might work but I don't recall where.

[Gary M]

just be sure the toilet can't drain, even a little bit, into the new grey tank plumbing. Also, your plan may result in the grey tank vent up top also being open to the black tank, so make sure you won't have an odor problem near the grey tank vent.

Very good points! My guess is that "funny" valve or whatever it is, was placed there to prevent blackwater from splashing/sloshing around back to the shower drain while towing. The black tank would have to be extremely full for this to happen, but I wouldn't trust that funny valve if the 2 systems were connected. I guess I could install a manual gate valve there, or a solenoid valve and wire in a switch. Either one would need to be somewhat accessible for repairs/replacement etc.. without having to remove the tub.

As far as the black tank venting into gray, I think I could set it up to have 2 hepv0 valves (1 on each side of the T fitting going to each different system). I could just relocate the one that's there now, and add a 2nd to the other side of the T

[Gary M]

Check the tank material before you decide how to install the new entry. The OEM fittings are usually welded in by spinning them to heat by friction. If the tanks are polyethylene no adhesive will stick. Somewhere I saw a compression/expansion fitting that might work but I don't recall where.

Yea I've seen those expansion fittings too Charlie. I think someone on here used one to relocate a FW drain to a lower point of their tank. Thanks for the heads up though, this is something I would have to research more. I saw a picture of an arctic fox tank buildup and it looked like they just used some type of cement, but I'll look into it more for sure!

[MitchB]

These were the fittings  https://www.usi-rv.com/product.sc?productId=9

[FastEddieB]

What a hassle. Good luck with that.

Our 2014 21BHS is plumbed correctly. But that leads to a question...

I've always considered "grey water" to be pretty benign. Our trailer has been pretty much in one location for a year. In that year and periodic stays we've twice made trips to a nearby dump station to get rid of the black water.

But I periodically just open the grey water valve and let it drain by where the trailer sits, in my case into gravel. Of course, it would be rude to do it in a public campground, but this is my own property.

For the most part, it's just soapy water from the sink and shower, right? It can smell a little musty, but next rain will take care of that. Or am I missing something?

[Merlin]

What a hassle. Good luck with that.

Our 2014 21BHS is plumbed correctly. But that leads to a question...

I've always considered "grey water" to be pretty benign. Our trailer has been pretty much in one location for a year. In that year and periodic stays we've twice made trips to a nearby dump station to get rid of the black water.

But I periodically just open the grey water valve and let it drain by where the trailer sits, in my case into gravel. Of course, it would be rude to do it in a public campground, but this is my own property.

For the most part, it's just soapy water from the sink and shower, right? It can smell a little musty, but next rain will take care of that. Or am I missing something?

I would consider it benign at your own (owned) campsite. It will have bacteria and viruses that survive the soap and will eventually build up a soapy scum. But you know where that is and I'm guessing generally avoid the specific spot where you drain. Rain and sun and decomposers will take care of it after a while. In a public campground it's very inconsiderate to drain your grey tank because the next camper gets to step in the wet mess left from the tank. And, not everyone is careful about what they put down the sink. After some tuna can drainage or other good smelly stuff gets in the tank from sink, here come the raccoons/skunks/bears/mice/dogs/etc attracted to the smell. Doing dishes outside and tossing the dishwater can have the same effect, but at least it gets dispersed.

As a relevant aside, if a 100 site campground were 80% full for the 3 month summer camping season and generated just 10 gallons of grey water per day per site, the campground would have 75,000 gallons of grey water dumped on the ground per season if everyone just dumped it. That would be a big mess, IMHO.

[ADR]

In a public campground it's very inconsiderate to drain your grey tank because the next camper gets to step in the wet mess left from the tank.

Not to mention it is actually illegal in many places.

In fact I've seen some where you aren't allowed to catch sink/grey drainage in an open bucket to be properly disposed of.  Has to go into a sealed external container.

[DavidM]

Merlin and I had a good natured argument offline about this point recently.

First of all our grey water is shower water and dish water where the plates have been first scrapped into the fire. No significant food and no coffee grounds. I could have washed those dishes outside using a collapsible water jug and dumped the water into the bushes and the rangers wouldn't have said a thing. Or taken an outdoor shower inside a canvas enclosure- and no one would object. But once you collect it in an RV tank then different regulations apply.

During thirty years of RV camping, I have probably dumped grey water at a public campsite 3-4 times. In each case but one there was a drop off to a very wooded "gully" for lack of a better word next to the camper. I ran the sewer hose to that area, about ten feet away and opened the dump valve.

The grey water was immediately absorbed by the leaves, vegetation and soil. There was no residual smell or soap scum. 24 hours later even the most vigilant environmental police couldn't tell I had dumped there.

Once I was camped in a level, gravel covered campsite. I dug a 6" deep depression right below the drain valve and slowly drained into that depression. After it had finished draining and there was no free water standing, I filled it in. Same thing about the environmental police.

Is it legal? Probably not. Is it harmful? Don't think so.

David

[Gary M]

I couldn't find an easy way to install a flange in the tank for pvc or abs, so I'm just going to use the largest blind bulkhead fitting they make (1" ID) and install it under the floor at the highest point of the tank I can get. I'm going to disconnect the hepvO from the existing pvc and turn it around. Then connect a 1 inch reinforced hose, or pex and run it through the existing hole for the shower incoming pex lines, and then straight over a few inches to the top of the tank.

First issue I've run into so far:

I cant reach my arm around the existing pipe to reach the hepvo valve. I'm in the process of removing the furnace now to cut an access hole in the azdel next to it. If I cut a big enough hole, I might be able to do this without removing the shower pan.

2nd issue: finding flexible hose or pex and a fitting or reducer to connect to the hepvo. The hepvo has 1 1/2" female connector on the end of it. I already ordered the bulkhead fitting for the tank. It comes with a barb that I can crimp a pex fitting on. Just trying to figure out how to connect the other end to the hepvo valve.

I've decided to hold off on hooking up the dual drain system for now because I have a camping trip coming up soon. I just ordered a 1 1/2" cap for the existing pipe for now.

Anyways.. back to work..

[Merlin]

In an earlier post, I may have made removal of the shower pan sound more difficult than it is. It's just time-consuming because you have to remove the bottom trim all the way around the shower. That would allow easy access to the drain, so it's worth consideration.