Any plumber will tell you, among all the things you must know in the plumbing world, the first two things you learn is: 1-Sh!t flows downhill, and 2-Payday's on Friday.
For me that means I don't have to pay someone else to do the work, and I need to keep a 1/4" vertical drop per horizontal foot.
That's similar to other runoff areas, like our garage conversion to living room had a 1/4" drop per foot rule of thumb the flat-work concrete guys TRIED to follow when they built our house long before WE got here, and that required leveling before making it a flat floor living room.
Likewise, when we put in our paver patio, I learned that was to be a 1/8" per foot slope, which allows general rain run-off without creating such a surface that you feel like you're in the fun-house at an amusement park.
And on the plumbing thing, you don't want a GREATER than 1/4" per foot, because if the water runs away too fast, the solids can get left behind, and that will create clog problems.
Now I'm not a plumber, but I did hear about a plumber's convention once!
Since I don't really have solids in this grey water line, more than 1/4" per foot is not too big an issue, but I do have set heights at several locations, the first in this galley run of course is the sink height which establishes the starting height of the trap and the spot where the downstream portion of the trap enters the horizontal (there's a name for that I'm sure, but - I'm not a plumber).
Then the next set height was the double copper elbow (like the magic bullet theory) of the cabinet exit, then down, then sideways, then back behind the cabinet!
It's here where the hope was always that the set height would be high enough to allow 1/4" per foot drop to the set height of the OTHER side of the camper where it elbows off the top of the fresh water tank, then elbows down, then on its merry way. Otherwise I'd need a lift pump, and THAT wasn't going to happen.
And actually, it wasn't always hope, it was verified certainty. I find verification and certainty always give me hope! So I try to verify and certify because... well - because... I like hope!
So way back ago, the placement of the copper elbows in the cabinetry were based on my knowledge that I had enough here for the slope, due to prior testing. But I always knew, I had absolutely NO room for error. So like the front wall cap, I've been saving this part for last, because I was afraid of it! You see, I still haven't found verification and certainty to prevent fear.
Fear is a constant, that's why we all walk around so defensive. Take away fear? Bam! No more ISIS! Take away fear? Bam! No more hunger! But I know I'm not supposed to talk religion and politics, so let me back-track again. I know you can always talk about the weather right? Take away fear? Bam! No more bad weather! Well - maybe it's not that simple. Guess I better re-think on that one.
We're looking under the fridge cabinet at where the copper reconnects back to the PVC by using a Fernco 1.5" to 1.25" adapter. The 1.25" fits the smaller outside diameter of the copper. This was more or less the last area assembled, because to find the height of the cabinet cutout notch, I first had to build and assemble the downstream area on the other side of the camper, but that's getting behind myself - let's keep correct flow in mind here.
And a view from below. Notice the slope? I couldn't get the level in here to prove it.
Then it runs across the top of the fresh water tank like this.
And the proof you were looking for, because like me, you may be dis-trustful!
And it's over here where we come into "Magic Bullet Theory #2". (And don't let my writing style cause you to think I'm making fun of an important consideration - regarding MOST conspiracy theories, I feel strongly both ways!)
Then, exiting the fresh water cabinet we enter under the dinette floor and into the grey water tank.
I'll place this strap clamp after I'm certain the pipe is in to stay.
And here's the big picture.
Now of course the logical question on many of your minds is, "why did you go OVER the tank. Wouldn't it have been easier to go along side the front of the tank at whatever elevation change was easiest?"
To which I answer, "Yes".
But surely you know me by now? I don't do anything because it's easiest! Because the space was there - I used it, but more importantly, because the camper is so small, I don't want to WASTE the space in front of the tank - it's reserved!
Here's an overhead view of that space.
These waste receptacles go there. Does it look like they'll fit in there?
Bam!
And the jury is still out on their use. Originally it was: 1-kitchen garbage, and 2-recycle items (cans and water bottles mostly). But since we have opened up a small area for kitchen garbage toward the back of the galley we now have additional options - like maybe one or two laundry hampers!
At any rate, the space is more wisely used this way. In another post soon to come - probably over in "Galley & Greatroom" - I'll show the build of the step platform around the waste line. THAT'S gonna be tricky.
But perhaps before that, guess what's ready to install under "Structure & New Wood"? Yep, final coat of poly...
And that coat fixed the area I was concerned about, that was just about here...