Gray water drainage design help (see drawing)

evy wrote:

2oldman wrote:

evy wrote:
When I can dump the gray water on the ground I simply remove the plug from the drain inside the pump's temporary tank, the water is drained so the pump never comes on.

You better buckle up.. it may get rough in here.

ok?

Just so you know here is Ohio's code

1501:41-9-07 Trailer plumbing requirements.
No person shall operate or bring into any camping area, any vehicle used for camping, and having plumbing fixtures with provision for outside drainage, which does not include

suitable, non-spilling holding tank which will not overflow and being connected with leak-proof couplings to a drain(s) that is controllable and will not allow any contents to be drained except into suitable park drainage facilities. It shall be permissible for drain(s) from the sink, wash basin, and shower to be drained into a suitable external holding device of a capacity of at least five gallons provided such device is not spilled, overflowed, or drained onto a campsite Any waste water disposed of at a state park shall be disposed of in an approved and marked park facility.

Effective: 12/15/2014
Five Year Review (FYR) Dates: 09/29/2014 and 12/15/2019
Promulgated Under: 119.03
Statutory Authority: 1541.03
Rule Amplifies: 1541.01, 1541.03, 1541.09
Prior Effective Dates: 6/14/75, 7/1/80
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Regulations at US National Forests

General Rules For National Forests
CAMPING

Camper holding tanks may only be emptied into approved designated facilities. Many campgrounds in the Forest are not equipped with dump stations, so you may have to travel to nearby communities to find an approved dump station.
Graywater from individual campsites, in small quantities, may be disposed of in the toilet facilities or else taken away from the campground and dispersed on the ground over a wide area.

Dumping water on the ground is legal and reasonable in a few places but not in (quite a few) others. Shower water may be permissible while kitchen sink water is not due to the food debris it may have. Typically neither would be permitted in city storm sewers, for example.

If you're intent on using the pump, I would eliminate the separate drain for the shower tank and just pump the water to the sink tank that may be drained or not as appropriate. I also would put the little pump tank/enclosure underneath the floor and insulate it appropriately so that it doesn't freeze up. Obviously even if uninsulated it generally won't freeze when the shower is actually being used, in as much as the warm water will be pumped out long before it gets cold enough to freeze. If uninsulated, you could put a little RV antifreeze down the shower drain after showering and leave it uninsulated.

You need a trap next to the shower drain; often one is built into the drain itself. You don't need a trap between the shower tank and the main gray tank. You do need both tanks to be ventilated to the outside. I'm not sure the check valve in the pump outlet serves any useful purpose, but maybe I'm missing something; for sure the check valve between the shower tank and the shower is not useful.

Most motorhomes have the gray and black holding tanks underneath the floor for rather obvious gravity and (especially for the shower) headroom related reasons. If you can plumb things without needing an additional pump, that's one less thing to break down, to have to turn on, and to get clogged with hair and soap scum.

I think your idea will work okay but, it seems to be complicating the process. The bilge pump is just something else to cause problems. It can clog or fail. And it will be another drain on your batteries.

Why not mount the shower holding tank below the flood and insulate it?
Eliminate the pump.

DutchmenSport wrote:
The holding tank under the sink will work just fine. But the tank the shower drains into will not. The tank will fill only as full as the height of the floor of your shower. That tank needs to be lower than your shower. If not, you'll have water standing in your shower.

A better option is to simply do away with the bilge pump idea and have 2 separate independent holding tanks with drains at each one. The tank still need to be UNDER the shower floor, unless you raise the shower floor.

I think you'll find the bilge pump idea will quickly be a PITA. Let gravity do what it does best, .... make water flow down hill.

You have room under the sink for a tank there, make room under the shower. Your toilet is a cassette port-a-potty style, so nothing to extra plumb there. It's self contained.

About dumping that water on the ground ... um ... you really need to rethink that.

Well here's how I planned it, I have to build my shower pan out of fiberglass, it's pretty tight in there, right now the free space is 32"Wide x 24"Deep x 72.5"High, I have to make a slope towards the drain, I planned that the lowest point in the shower floor would be 2.5" higher than the bottom of the bilge pump pan, and the pump would automatically start when about 1.5" of water is in there, so theoretically the shower pan would always drain.

I can't raise the pan to add a tank underneath I don't have enough head space for that, so I would have to add it under the van, exposed to the cold and freezing weather...

Please give me more detail why the pump idea would be a "PITA" like you say, I simply want to understand why.

Revise your floor plan and place the sink sharing a common wall with the shower.

2oldman wrote:

evy wrote:
When I can dump the gray water on the ground I simply remove the plug from the drain inside the pump's temporary tank, the water is drained so the pump never comes on.

You better buckle up.. it may get rough in here.

ok?

The holding tank under the sink will work just fine. But the tank the shower drains into will not. The tank will fill only as full as the height of the floor of your shower. That tank needs to be lower than your shower. If not, you'll have water standing in your shower.

A better option is to simply do away with the bilge pump idea and have 2 separate independent holding tanks with drains at each one. The tank still need to be UNDER the shower floor, unless you raise the shower floor.

I think you'll find the bilge pump idea will quickly be a PITA. Let gravity do what it does best, .... make water flow down hill.

You have room under the sink for a tank there, make room under the shower. Your toilet is a cassette port-a-potty style, so nothing to extra plumb there. It's self contained.

About dumping that water on the ground ... um ... you really need to rethink that.

evy wrote:
When I can dump the gray water on the ground I simply remove the plug from the drain inside the pump's temporary tank, the water is drained so the pump never comes on.

You better buckle up.. it may get rough in here.