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Talisman61's avatar
Talisman61
Explorer
Feb 19, 2018

Single waste holding tank

While I'm working on a TC, I figured those of you in here would be better suited to answer this question.

I'm adding holding tanks to my $500 TC that has become a budget minded build. Not out of necessity, but because she's a 1971 unit that I'm not sure how much life is left in her.

Anyways, I need a black tank, and should probably add a gray tank as it's illegal to dump gray to ground.

Can I use a single tank for gray and black? I have a few reasons why this would be far simpler than 2.

1. The plumbing on this camper was originally designed to go to ground, so I dont have much room under it for pipes. with the kitchen sink on one side, and the shower,bathroom on the other with the toilet, it'd be nice to drop straight down after the traps to the tank rather than plumb together then to a tank.

In order to get both sides connected, I'd have to have piping below the top of the tank, not ideal.

2. Cost, one big enough to hold both gray and black is actually quite cheaper than 2 smaller ones considering the space I have to work with. I only have ~6" of height to accommodate a tank.

The downsides are what I'm coming to you guys for.

I see concerns with flushing when dumping, any smells will possibly come up the sinks if a vent has issues, and sloshing while travelling.

I have a 45" wide, 45" long, 6" tall space to work with if you have suggestions.

Sorry for the long post!
TIA!

28 Replies

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  • arkie_guide's avatar
    arkie_guide
    Explorer
    Feb 25, 2018
    I installed a single tank on my small TT, The 2 of us do not take 2 showers apiece ever day. So it works just fine.
  • Talisman61's avatar
    Talisman61
    Explorer
    Feb 21, 2018
    2oldman wrote:
    Talisman61 wrote:
    Most if not all places I've been we are allowed to dump gray to ground or have sewer on site.
    Ok. Your OP seemed to say you'd never be doing that. That will put considerably less pressure on the single tank idea.


    Ah my bad. Everytime we have had this camper out we dumped gray to sewer or ground, legally. I just want to plumb them together into the single tank, with an optional cutout at the sink for when we can dump to ground legally.
  • drsteve's avatar
    drsteve
    Explorer
    Feb 20, 2018
    donn0128 wrote:
    Install a black tank and buy yourself a tote tank to handle the gray water. Otherwise install two tanks.


    Yup. My 1973 Terry TT was like that from the factory.
  • 2oldman's avatar
    2oldman
    Explorer II
    Feb 20, 2018
    Talisman61 wrote:
    Most if not all places I've been we are allowed to dump gray to ground or have sewer on site.
    Ok. Your OP seemed to say you'd never be doing that. That will put considerably less pressure on the single tank idea.
  • Talisman61's avatar
    Talisman61
    Explorer
    Feb 19, 2018
    coolmom42 wrote:
    2oldman wrote:
    Talisman61 wrote:
    I considered putting a tee with valves just below the kitchen sink for those sites that let us drain to ground.
    Ok, so gray on the ground is not out of the question.


    Depends on where you are.

    Illegal in some states.

    Specifically banned in many national parks, such as Glacier. BUT those parks often have big sinks that are intended for disposal of dishwashing water. You could dump some gray into a bucket and pour down that type of sink if available. Or dispose of it into a flush toilet.


    Exactly, I can add that so where possible I can use it. Most if not all places I've been we are allowed to dump gray to ground or have sewer on site. That would only be for the sink, as the shower I won't have enough room to add a "cutout"
  • coolmom42's avatar
    coolmom42
    Explorer II
    Feb 19, 2018
    2oldman wrote:
    Talisman61 wrote:
    I considered putting a tee with valves just below the kitchen sink for those sites that let us drain to ground.
    Ok, so gray on the ground is not out of the question.


    Depends on where you are.

    Illegal in some states.

    Specifically banned in many national parks, such as Glacier. BUT those parks often have big sinks that are intended for disposal of dishwashing water. You could dump some gray into a bucket and pour down that type of sink if available. Or dispose of it into a flush toilet.
  • 2oldman's avatar
    2oldman
    Explorer II
    Feb 19, 2018
    Talisman61 wrote:
    I considered putting a tee with valves just below the kitchen sink for those sites that let us drain to ground.
    Ok, so gray on the ground is not out of the question.
  • Talisman61's avatar
    Talisman61
    Explorer
    Feb 19, 2018
    westend wrote:
    I have a single tank. The grey water is valved off from the main 3" drain and single tank. The drain end cap has a 3/4" hose fitting for diverting drain water beyond the end cap. My bathroom sink drains directly into the single tank.

    I may add another tank as that would give me additional grey water storage.


    Going the single route, having to reroute and redo all the pipes anyways, I considered putting a tee with valves just below the kitchen sink for those sites that let us drain to ground.
    This would be easy to add down the road though if we start having water issues.
  • westend's avatar
    westend
    Explorer
    Feb 19, 2018
    I have a single tank. The grey water is valved off from the main 3" drain and single tank. The drain end cap has a 3/4" hose fitting for diverting drain water beyond the end cap. My bathroom sink drains directly into the single tank.

    I may add another tank as that would give me additional grey water storage.
  • Talisman61's avatar
    Talisman61
    Explorer
    Feb 19, 2018
    SoundGuy wrote:

    Why bother adding any tanks at all, especially if this is a budget DIY. Invest in a porta potti and you've eliminated the need for a black tank, invest in a couple of inexpensive 7 gal Aquatainers, gang 'em together, and drain your grey water directly into the 'Tainers sitting on the ground - no need for a grey tank. And yes, I did just this with a previous popup camper ... works just fine. :B



    If I'm being deadly honest, my wife has some say in what happens, and hates portas and recirculating toilets.

    Also, my parents had one in a pop up that got smashed when we were kids. It wasn't a pleasant experience, not even sure how dad pulled off smashing it.

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