Gray water drainage design help (see drawing)

evy wrote:

DutchmenSport wrote:
Even with your revised plan, the tanks themselves need to be vented, otherwise you've created a vacuum in them. If you don't have the sink tank open and draining, and the bilge pump is running, after the sink tank pressurizes, you'll start having water shoot out that vent. If there was no water in the p-trap in the sink, then the p-trap would serve as a vent. The vent needs to be just higher than the drain, that's all, but going to the actual tank so as it fills with fluid, the air can escape.

Reason why I said the pump would be a PITA, as stated above.... power failure, clogs, running your battery down, potential leaks. And how do you drain that system once the heat is turned off in the camper if you're not using it and temps get below freezing? Can you remove the bilge pump and winterize it? I suppose you can pour a couple gallons of "pink stuff" down the shower and feed it through the system, that would winterize it.

Ok that makes sens, I took the P trap out to directly vent the tank outside. The tank that the bilge pump sits in has no cover since the water will only go back in the shower pan if the bilge pump stops pumping.

I will try to take another look at the van inside and out to find a spot I could add a second tank underneath the shower but the big gas tank and propane tank are right underneath...

Your plan is basically a huge failure.

Check valves are a huge source of failure along with the bilge pump..

Your shower is going to collect HAIR, that hair will eventually end up fouling the pump and or check valves.

Not to mention the check valves if they do not fail will end up trapping WATER in that overhead line.. That WILL result in a frozen line and most likely break the line in the process.. That will spray grey water everywhere..

Your best bet is to stop, tear out and start over, cut your losses and redesign the whole PROPERLY so you don't need all this complexity.

BUT, since you seem to be bent on your plan, do yourself a huge favor and skip the entire bilge pump and pipe over head and go with a grey tank large enough to deal with your shower time on the side of the shower. Then put a drain connection to the underside.

Then after your shower you can connect a transfer pump outside from the shower tank to your main tank.. For your main tank you would have to setup a inlet on the side just above that grey tank.

When finished transferring you can unhook the pump and hose and store.