Orton DIY - Gray Water Tank

[Graphite Dave]

14 ga. 304 SS Tank is 8" wide x 9" tall x 36" long and holds approx. 10 gallons. There are two 1" inlets for the sink and the shower. One on rear end and one on the side. Both inlets are welded close to the bottom so when tank has water in it the infeed hoses will act as a trap. 1" heater hoses will be used to connect the drains to the tank. There is a 4" x 8" cleanout hole on the bottom covered by a 6" x !0" 10 ga. plate. A 1/2" vent elbow is welded at the top of the side and in the middle of the tank.
The tank will be bolted to two 8" long pieces of 80/20. The 80/20 will be bolted to the Sprinter floor support ribs on the left side in front of the rear wheel. 80/20 will be on one side of the rib and a 1/4" x 1 1/2" x 6 1/2" SS plate will be on the opposite side of the rib. Rib is sandwiched between the 80/20 and the 1/4" plate. Two 5/16-18NC x 3" carriage bolts will pass through the rib at each end of the tank.
The outlet is a 3/4" half coupling. There is a 3/4" ball valve and then a quick disconnect hose coupling.
The tank tucks up inside the Sprinter side so no part of the tank is visible from the street.

 

[Graphite Dave]

Installed tank. Hardest part was drilling the Sprinter ribs for the 80/20 through bolts while laying on my back under van. The picture with the loose tank is a bottom view showing the cleanout hole with a 10 Ga. cover. Used 1/4" closed cell foam as a gasket. Also made a screen for the floor vent opening to keep the mice out. Modified a house air vent for screen. Shower pan is not installed so just temporarily put on a 1" hose and terminated it above the top edge of the tank. Red hose is the 1/2" overflow. Sink 1" hose is the 90 coming out of the screen. Tank is hidden from outside view. The 3/4" outlet can barely be seen. Attached is a PDF of the tank design.

 

[teamtexas]

Your tank looks great! I don't know if you will have the same problem I'm having on mine. I have the shower drain into the high end up close to the top of the tank. I installed a p-trap to keep sewer gasses from coming back out into the shower. This all seems to work fine until I try to travel with a 1/2 tank or more grey/black water. I find that if I stop hard the water is forced up the shower drain, even though I have baffles built into the tank.

May need to install a check valve to stop the problem.

Dan

 

[Graphite Dave]

Thanks. We will see if the water comes out of the shower drain hose. I do not have the shower drain installed yet. Both of the drains are located at the bottom of the tank without P traps. I am hoping that with water in the tank the low inlets will act as a trap. Did not add baffles because I wanted easy access for cleaning. Tank is 3' long so water movement may be a problem. Fortunately I do not have any openings in the front half of the tank so may not get the water pressure on a fast stop. I think I will need rubber plugs in the sink and shower as well.

This week I will be on vacation in Monterey for the Auto activities. It will be the first time I will have running water. Since van is very stealth, I can park it almost anywhere for the night.

 

[Graphite Dave]

After thinking about your comments: Probably better to have the drain connections close to the bottom of the tank below the wave, have the connections at the back of the tank instead of the front so sudden stops do not force water forward (good the van acceleration is slow) and use drains that have a stopper that locks in place. The drain fittings I used came from West Marine and have a stopper that you twist to seal the opening to retain water. I suspect they will work in reverse to keep water from back flowing. Thanks for your comments. Never thought about backflow into the fixtures.

 

[Graphite Dave]

My 5 day test of the gray water tank showed one mistake. The two 5/16-18NC cleanout plate bolts need to be sealed. Need flat washer with a gasket or O-ring of some sort. Seems I installed an automatic drain gray water tank. Got dripping from both boltheads. Otherwise tank and plumbing worked great.

 

[Ski_Bike_Camp]

As usual beautiful work ...

I didn't bother with grey water tanks at all. I just have them exit straight down to daylight.

My thinking was, if I had to trap and keep soapy water, I could do it with a bucket of a collapsible tank on the ground.

We also didn't do a black water tank and opted for the newer style cassette porta-potty.

My main reason for keeping these systems simple was to avoid any chance of having something freeze while going down the road in the winter.

 

[Thanasis]

Very professional work. What a contrast to my solution:
https://sprinter-source.com/forums/showthread.php?t=14398

... but it works for us. I have replaced the drain 'faucet' with a ball valve, since these photos were taken.
Thanasis

 

[Aqua Puttana]

Your tank looks great! I don't know if you will have the same problem I'm having on mine. I have the shower drain into the high end up close to the top of the tank. I installed a p-trap to keep sewer gasses from coming back out into the shower. This all seems to work fine until I try to travel with a 1/2 tank or more grey/black water. I find that if I stop hard the water is forced up the shower drain, even though I have baffles built into the tank.

May need to install a check valve to stop the problem.

Dan

You might be better off installing a slide valve or ball valve and manually close it for when on the road. A slide valve might be fitted with a removable extention operator which would avoid the need to crawl underneath. Typically check valves are not very effective in wastewater applications because they get mucked up and either stick open or closed. Either situation may cause you to need to open the system to correct the problem. Not fun when getting paid to do it, much less fun if on vacation. FWIW. vic

 

[Graphite Dave]

Ski-Bike-Camp: The tank gives a choice. Can be left empty in cold weather of used in warm weather. I stealth park in cities so can not show a bucket or let it drain on the ground. I also decided against a black water tank due to the cleaning requirements and where do you store the drain hose. My portapotty is easier to dump and clean. Seldom used. The pee bottle is easier to use and clean than the portapotty and a lot more portable. I fiqure the reason Mc Donalds was established is to provide for people like me. I pass on the food but not on the bathrooms.

Thanasis: Who cares what it looks like as long as it works. Not many people crawl under a van to look at a gray water tank. Mine is stainless because I traded some engineering design time for the tank fabrication. Without that choice, I may have fabricated it out of PVC sheet. Cut pieces to size and glue it togrether for a custom size tank. Glue in PVC fittings for the inlet and outlet holes.

TeamTexas: Do not know what your drain looks like but they do make rubber plugs for pipe that you put in the pipe end and turn a wing nut to expand the rubber for a tight fit. Would that work?

 

[Graphite Dave]

Teamtexas: Had one of the plugs and my shower drain so tried it out. It works on my shower drain.

 

[Aqua Puttana]

Teamtexas: Had one of the plugs and my shower drain so tried it out. It works on my shower drain.

Seems like a nice simple solution. Certainly easier than installing a check valve or other valves. vic

 

[Graphite Dave]

Gray water tank and shower drain pan are installed. There is a 12" long straight 1" hose between the shower pan and the gray water tank inlet. No trap. Hose enters 10 gallon tank on side of tank at the bottom in the middle of the 3' long tank. Theory is with any water in the tank, the water will create a water seal at the bottom of the hose. Have not smelled any odors yet. Tested for the backflow up through the shower pan drain. Filled gray water tank to overflowing and then drove it with many starts and stops. No water backflowed into pan. I think the reason I do not have a problem is the location of the inlet to the tank. Being in the center and down low under the water level, the sloshing wave does not force water up the drain hose. If the hose was attached to the front of tank at the top, I can see how a wave in the tank rushing forward would force water up the hose.

 

[GeorgeRa]

Dave,

Why did you choose SS instead of generic or custom plastic tank? I will be installing grey water tank in the same location in front of the 21" long Isoterm water heater. Stainless is likely heavier, you tank is about #30 lbs and plastic could be about 1/3 of that weight. Did you compare costs of custom stainless versus polyethylene or polypropylene tanks?

http://www.plastic-mart.com/product/928/7-gallon-rv-holding-tank-9h

George.

 

[Graphite Dave]

I traded some engineering time for the tank. Several hours labor for the tank. It should be pretty easy to make a gray water tank out of PVC sheeting instead of SS. Buy some PVC angles to glue in the corners at the bottom and top of the tank so you have some surface area for the glued joint. 1/4" sheet with 1/8" or 3/16" x 1 1/2" angles. Have top overhang at each end for a flange to bolt to Sprinter the same as my SS tank. Use a flatbar under flange.

 

[GeorgeRa]

Dave,

I found a 9 gal. tank which would fit (30.25" x 10" x 9") but would prefer a larger tank with better fit. How is the vent line working for you? Is it just straight fitting or more elaborate one to minimize water exit?

For the fresh water tank I will need a custom tank under the sliding door.

Both these tanks will need to be vented but commonly used roof venting is not my option.

Thank you,

George.

 

[Graphite Dave]

Post # 1 shows the 1/2" OD vent SS tubing. At top edge of tank in the middle. Post # 2 shows the 90 degree fitting with the red overflow hose. Hose stops just below bottom of tank. Nothing fancy. Just tested it driving out of the IN&Out Burger parking lot in Gilroy on my way home. Long line of water following the van. I pumped fresh water into the tank to fill it so driving through SF stop and go traffic I could test it to see if water backed up into the shower pan when tank was full. Put in too much! No water in the shower pan. Do not care if water exits. Gray water will not hurt anyone.

For the fresh water tank which on my conversion is located inside under the right rear bench seat. I put the vent line on top of the tank in the center of the length and then ran plastic tubing forward and then up behind the sliding door. Topped the tubing with a pneumatic valve exhaust muffler. Have not seen any overflow and muffler keeps out the bugs. It is very porous plastic fitting. White vent tubing shown in "ortonDIY - under right rear seat". Post #2 under "orton DIY - misc." shows the termination of the fresh water vent with the muffler.

Both tank vents should be located near the center of the tank lengths to prevent overflow when stopping.

 

[GeorgeRa]

Post # 1 shows the 1/2" OD vent SS tubing. At top edge of tank in the middle. Post # 2 shows the 90 degree fitting with the red overflow hose. Hose stops just below bottom of tank. Nothing fancy. Just tested it driving out of the IN&Out Burger parking lot in Gilroy on my way home. Long line of water following the van. I pumped fresh water into the tank to fill it so driving through SF stop and go traffic I could test it to see if water backed up into the shower pan when tank was full. Put in too much! No water in the shower pan. Do not care if water exits. Gray water will not hurt anyone.

For the fresh water tank which on my conversion is located inside under the right rear bench seat. I put the vent line on top of the tank in the center of the length and then ran plastic tubing forward and then up behind the sliding door. Topped the tubing with a pneumatic valve exhaust muffler. Have not seen any overflow and muffler keeps out the bugs. It is very porous plastic fitting. White vent tubing shown in "ortonDIY - under right rear seat". Post #2 under "orton DIY - misc." shows the termination of the fresh water vent with the muffler.

Both tank vents should be located near the center of the tank lengths to prevent overflow when stopping.

Thank you Dave,

Good point for the middle mount for the vent. The sink will be the only drain so I could vent the tank from the drain line by teeing-off from the vent line just above the tank and vent it high up into the engine bay. The drain line will be attached to the top of the tank. I am still looking for a reasonably priced 0 pressure solenoid drain valve so I don’t have to kneel down at the often not very clean dump station.

The fresh water tank will be located under the floor where the standard DEF tank is located (my DEF tank is in the engine bay). The fill and vent lines will be accessible from the engine bay.

I will ask for quotes from the custom tank manufacturer in Tacoma for water and gray water tanks. They use welded 3/8” polyethylene. I assume they could be around $300 ea. including 3 fittings per tank. The level sensors are flange mounted so they can weld a flange collar as one of the fittings.

George.

 

[Graphite Dave]

Sink drain should attach to side of tank at the bottom so you do not backflow out the sink drain from wave pressure. Probably would not be a problem with sink because drain is about 2' above floor but? Low attachment also acts as a trap to eliminate tank smells.

My gray water drain is a ball valve and can be reached without kneeling on ground. I know about where it is so reach up under van side to feel the valve handle and then turn it.

 

[GeorgeRa]

Sink drain should attach to side of tank at the bottom so you do not backflow out the sink drain from wave pressure. Probably would not be a problem with sink because drain is about 2' above floor but? Low attachment also acts as a trap to eliminate tank smells.

My gray water drain is a ball valve and can be reached without kneeling on ground. I know about where it is so reach up under van side to feel the valve handle and then turn it.

I have sink u-trap so odor will not be a problem. A ball valve will likely by my option of I will not find an inexpensive solenoid valve. With the recent quote for both tanks of $812.17, the real ouch, I could revisit SS or glued PVC but I hate the smell of cyclohexane, the PVC glue.

George.