Forum Discussion

bearsnob's avatar
bearsnob
Explorer
Mar 10, 2015

Gray tank leaking

My grey water tank started leaking all of a sudden, only when full. My fist thought was it must be a fitting but, when I pulled down the underbelly, it seems to be leaking someplace on top of the tank. It's running out like as if a plug fell out. In other words, the tank isn't swelling at all and the water seems to be coming out as fast as it's going in. Problem is, I can't see anything as there's less than an inch of space.

Unless someone has a better idea, I think I have to drop the tank. If I do that, I'd appreciate some recommendations as to where I cut the ABS pipes. I can't see an easy way to do it traditionally on the left drain. I'm thinking I just cut the last elbow in the middle and then patch it with a Fernco product or something similar.

Before I do anything, I'd appreciate any thoughts or advice you guys have. It looks easy enough to drop the tank. It's just those two drains, disconnecting the knife valve, and unbolting a rail from what I can see. Here's a picture of the drains going into the tank:

Click here to view picture.

Thanks in advance!
  • bearsnob's avatar
    bearsnob
    Explorer
    Mar 12, 2015
    This is scary. I think I figured it out on my own at Home Depot. The key is a short 90 degree "street" elbow. The street elbow is female on one end and male on the other. Because it's short, you get about an inch longer to work with on both ends. So if I cut out that last elbow going down to the tank, I should be able to use couplers to lengthen the pipes. If I get in a bind (things not exactly matching up), I can use a flexible coupler. I was confident enough that I bought the parts. If all goes well (i.e., the tank can be repaired), maybe I'll have good news to report soon with pictures.
  • bearsnob's avatar
    bearsnob
    Explorer
    Mar 11, 2015
    srt20 wrote:
    I had my gray tank leak only when completely full. The pipe going into the tank wasn't sealed good. I put a hose clamp on and got it tightened the best I could. I also bought some of that "flex seal" stuff. It wasn't the brand seen on TV but a brand from the local hardware store. Hasnt leaked since. Mine is a MH in a heated compartment. And it would be a huge PIA to take the tank out. So I tried this first.


    The way these things are built, that's the first place I checked because it was easiest to see. The joints are glued/welded exceptionally well. In fact, all the abs pipe Looks like it was done well. Kind of surprising but then how hard is it to learn how to glue abs pipe? You can be pretty skilled in about a day.

    I guess I just have to figure out where to cut. Hmmm...behind that last elbow is about an inch of pipe. Maybe there's something I can do to get that to work. The problem is the elbow has to line up with the tank (or I have to reposition the tank and modify the connection to the sewer line).

    I'll check with a plumber tomorrow. Thanks for all the ideas. And yes, it is a PITA. I just hope I find a simple problem once I get the tank down.
  • bearsnob's avatar
    bearsnob
    Explorer
    Mar 11, 2015
    I would would be surprised if that was the cause because these tanks are in really secure, especially compared to my fresh tank that Keystone put in wrong twice (it dropped out twice--second time they payed me to install it because I told them I wasn't going to risk someone being killed by their negligence).

    That said, I've heard these tanks just crack sometimes and I'm hoping that's not the case because they aren't cheap and it also appears they aren't being made anymore. I guess I'll find out once I have a good plan for how to cut the plumbing. I'm all for doing things right, but that's an insane number of joints going in on the left. They're not even all in the photo. There's not even a way to simplify it that I can see. Plus it's a tight space.
  • srt20's avatar
    srt20
    Explorer
    Mar 11, 2015
    I had my gray tank leak only when completely full. The pipe going into the tank wasn't sealed good. I put a hose clamp on and got it tightened the best I could. I also bought some of that "flex seal" stuff. It wasn't the brand seen on TV but a brand from the local hardware store. Hasnt leaked since. Mine is a MH in a heated compartment. And it would be a huge PIA to take the tank out. So I tried this first.

    It had probably been loose since new, but the gray tank had probably never been that full before.
  • Hiking_Hunter's avatar
    Hiking_Hunter
    Explorer
    Mar 10, 2015
    bearsnob -
    I've recently read on another forum about black and grey tanks splitting in their seams because they were not adequately supported underneath. Seems like Keystone is one manufacturer that decided to leave off the support straps and mount the tanks only be the molded flanges. Can you tell if this might be your problem?
  • bearsnob's avatar
    bearsnob
    Explorer
    Mar 10, 2015
    Thanks. That sounded like it might be it. But then I couldn't remember seeing a vent pipe. Just looked and they've attached the vent to the drain pipe for the shower/kitchen sink. So the vent doesn't attach to the tank. I can't find a good picture of the tank online to see where fittings might be. Also, I was wrong about the clearance. There is no clearance for most of the top of the tank. The only clearance is where the two drain pipes insert.
  • Dr_Quick's avatar
    Dr_Quick
    Explorer II
    Mar 10, 2015
    My guess it that the tank vent line to the roof may be loose or not sealed. If there is some way that you could take off the roof top vent cap and try to pull up on the vent line or twist it. If line is loose that may be your problem. Or on some trailers the lines are exposed in a closet, check it there.

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