How to buy gray tank?

Jaybus

Advanced Member
Joined
Sep 8, 2011
Posts
77
How do you know where to put a gray water tank and what one to buy?
And you put the toilet right over the top? :facepalm: my god I cant even drill a hole for a toilet because I dont know where it goes! :bow: help

Photo 5 years ago and its the exact same.

Do you measure the bus frame then order off plastics website?
 

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How do you know where to put a gray water tank and what one to buy?
And you put the toilet right over the top? :facepalm: my god I cant even drill a hole for a toilet because I dont know where it goes! :bow: help

Photo 5 years ago and its the exact same.

Do you measure the bus frame then order off plastics website?

Grey water is from sinks and showers. Black water is from toilets. Most people drop their toilets directly into the black tank so you need to find a spot for the tank before mounting the toilet. Using a porta-potti makes your build way simpler.
 
anytime i had to drill a hole, the bus work just stopped for a few days until i was absolutely sure.

get your tank mounted first, don't drill the hole until after your tanks are in and you have the toilet. you'll need to know the setback of your toilet so you can open the lid and such.
 
How to know where the tank goes? It's a tug-of-war between several things, including:

  1. where there's room for tank and maybe pipe down below, ie no/minimal interference from other bus structures,
  2. how many gallons you want to hold, and
  3. whether the position of the fixtures inside matters to you.
Convention (in the US/North America) is that the clean out would be on the left side of the bus/RV; plumbing is minimized if the tanks and fixtures can go on the left side also. Definitely it's a plus to have a black tank directly below the toilet as roach described; it can save some headache to have the gray tank directly below the sink too. It's tricky to put a gray tank below a shower/tub because there needs to be space for a P trap or Hepvo valve between those two.
 
I'm using a 110 gal fuel tank that's been boiled out for my grey tank, fits between the frame rails right in front of my fuel tank, I mounted a 33 gal black tank & I'm using a Macerating Toilet to pump to the black tank, then I'm using a Macerating pump to empty the black tank,then I'm using another pump to empty grey tank into black to flush the black tank, sounds more complicated then it is.
 
I found this for $10 at a garage sell.
It looks ok but the gate valve leaks so I cant tell.

If I mounted it the clearance wont be as good as under the ribs of the frame but it would be cheap











 
I found this for $10 at a garage sell.
It looks ok but the gate valve leaks so I cant tell.

If I mounted it the clearance wont be as good as under the ribs of the frame but it would be cheap












If the gate valve outlet is just a piece of pipe that has been cut off then you still have some options? You drain the tank and cut the old useless valve off cause it needs to be replaced (18$ at the rv place here) and get a glue cap for 3-5$, a rubber test cap for 3-5$ and re-use it over and over, or buy a roll of good duct tape and dry/clean the pipe off on the outside good, cover the end of the pipe with several pieces layered that fold down/up the end of the pipe by 3-4"'s and then wrap around the end of the pipe to secure the tape folded over the end of the pipe. Not re-usable but workable and the rest of the roll is there for other things? Or you can cap/plug the other opening's in the tank, buy an elbow and piece of pipe to glue onto the gate valve end and do a real pressure test on the tank itself?
The higher off of the ground the tank is the higher the pressure is going to be.
For non pressurized (not bragging but I put 80-psi on mine before install but I had the resources at the time) for dead water weight as I call it for every foot above the ground/gravity level there is a 2.31 PSI pressure increase.
The pipe and elbow I mentioned to glue onto the gate? If you turn an elbow up with a 10' piece of pipe and fill it up to the top then your water pressure will be roughly 20-22 PSI.
As explained to me quite awhile ago?
If you have a 1/2" pipe stuck up 100' in the air with a 20 gallon tank and right beside it you had a 24" round pipe stuck up in the air 100' with a500,000 gallon tank on it? Which one would have the most pressure?
They will both have the same pressure because they are both at the same elevation above the ground/gravity line? Thought it was useless knowledge stuck in my head with my knew job and maybe it helped but now it's knowledge useless or not for your head?
 
Water column is a great way of testing pressure.. though one should remember when comparing that 1/2" pipe to the 24" that the small one is going to sting like a water jet, whereas the large one will hit with so many pounds of water so fast it'll wash you right out of your socks! I remember testing a shallow sewer lateral once and being surprised at the force of a 6 ft column of water rushing through just a 4" pipe when I deflated the test ball.

By the way, that conversion factor is inverted. It's 2.31 feet of head per psi, or about 0.4 psi per foot of head.
 
Correct sir and I knew i had the numbers mucked up somewhere? I have been doing fire sprinkler commercial since Christmas so all the numbers in my head are throwing me off? Sorry
 

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