Plumbing problem, sink water fills up bathtub?

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marknoo

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Sep 20, 2016
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I have a 1996 Nomad trailer. When I turn on either the kitchen or the bathroom sink water the water flows into the bathtub. I took out the gray water valve on the outside of the trailer and ran a snake up it as far as it would go by hand. Maybe 4 or 5 feet and nothing. I expected there to be either a faulty valve or some other obstruction and to get soaking wet but nothing happened. The snake went right up there.

Underneath the trailer there looks to be a T in the plumbing where (it looks like it is a radiator type hose fastened with a screw type tightener connects the holding tank with the pipe leading to the final valve that releases the water into a hook up or plumbing.

I think the pipe that connects the holding tank to the final release valve also works as the plumbing for my bathtub.  How is it that water can flow into my bathtub but not out of it?

Here are some links to pictures, I don't know the proper names for any of the parts I have mentioned, so I thought it might give you a frame of reference.

https://imgur.com/cfXEU8x
https://imgur.com/uuCBypk
https://imgur.com/KNoVRvP
https://imgur.com/B6tsD2v


I thought I could try one of those "gel" type clog removers but how do I get that past the traps in the sinks and to where the clog is. Or would that work at all.
 
Dang I wish I had patented that flex line idea (Did that in my parents house oh about 40 years or so ago when they made some changes that resulted in the need for a flex line).

From what you have said there is a clog, either the outlet of the "T" fitting or the hose.. Only candidates.. Since I assume the tank is empty  from the "Ran a snake up" line.
 
How long is that run of pipe from the drain to the flex coupling? That looks like it could be close to 4-5 ft (hard to get a sense of scale in the pic) and you haven't actually entered the tank yet to see if there is a clog at the drain opening of the tank.

Also, if there is a vent stack to access from the roof, it might be worth sending the snake down the vent pipe into the tank to check if the tank has anything in it. Could even just try from one of the sink drain lines toward the tank.
 
It's not uncommon in both houses and RV's that the vent pipe is also used as a drain line for sinks, etc. It's called a "wet vent". You could try running water from a hose down the vent from the roof with the grey valve closed to see if it's clear into the tank. If that works ok and you can't feed the snake down the bathroom sink drani try dropping the trap under the sink and running your snake through the drain line. It may be clogged at the sanitary 'Y' fitting where the drain connects to the roof vent line or a 'T' where the tub and sink lines join together.
 
I'm guessing you have a clog where those sink and tub drains Tee together, somewhere in the stretch before the combined pip reaches the gray tank. Any clog there, or in the tank itself, backs up into the tub or shower first, because that is the lowest point.

Any drain cleaner might help, but the gel kind is not an advantage in this situation. The liquid types will more easily pass through the traps and reach the clog. However, the waste water already in the pipe dilutes it, so it may not be very effective. Can't hurt to try, though.

The other choice would be to remove a drain trap and run a snake down toward the Tee and the tank.
 
John From Detroit
Are you suggesting that I go up to the flex hose and undo it. Maybe poke around in there a little bit?

Hammster
It is about 4 or 5 foot, so I guess my snake went straight up that pipe and stopped at the T.

NY_Dutch
The vent to the roof should be directly above the tank, right? That is what I should pour water down?  What if I poured my drain cleaner down that?
 
It is about 4 or 5 foot, so I guess my snake went straight up that pipe and stopped at the T.

If you put the snake in from the tank drain side, how did it even get into the drain line coming into the tank? Takes a lot of luck pointing that snake...

There is no valve between sink or tub and tank. Just the trap in each line that prevents gases from returning to the sink or tub.
 
I don't think it did. I think it went up the 4 or 5 foot straight stretch of pipe and then stopped. 

What if I put one of those black rubber things that let you put your garden hose into it and blow it out in reverse.  You know, the black rubber fills with water and expands stopping water from coming out of the pipe and then the pressure of the garden hose  forces any obstruction out.


Would that work, maybe?

The water being forced into the system should then go into the bathtub, so I don't think it would create a huge mess.
 
I don't know about your setup but our drains were sluggish during our last trip.  After we got home Jerry put a hose down the kitchen sink drain and said a lot of gunk blasted out through the drain hose.  I suppose after 10-15 years there's bound to be some buildup.  It's no longer sluggish.  He did the same thing with the bathroom sink and the shower drain.  Just be sure to have lots of old towels handy!  And be ready to turn the water off quickly.  My one hesitation in telling you to do it is that some rigs have two different gray water drain valves and I don't recall your mentioning anything like that.  I don't know if that could affect what's happening in your rig or not.  I sure hope you'll let us know what finally clears it!

ArdraF
 
I am suspecting the issue is in one of 4 places depending on how bad the problem is

IN line order

1: The "T" the side that connects to the hose
2: The hose
3: The connection between the hose and the tankj
and 4: The tank vent line.. This only applies if you need to run a LOT of water before it comes up when the tank is empty and not so much if it's full,,


One other possibility.. Inertia  IF the "T" is near the tub and the sink is a long distance.. But then it would come up and instantly go back down, .
 
marknoo said:
NY_Dutch
The vent to the roof should be directly above the tank, right? That is what I should pour water down?  What if I poured my drain cleaner down that?

Yes, that's the idea to make sure the vent is clear. And yes, it usually does go straight down to the black tank, although in a single vent setup, there's 'Y' where the grey tank vent connects to it. Separate vents for the two tanks aren't usually done when the two are mounted close together. I'd try just the water first, and if it runs down into the tank without backing up then using drain cleaner in there would not help.
 
stick a camera scope down the 2 drains and look for the blockage.  15 bucks on amazon.


https://www.amazon.com/gp/product/B072179BTL/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1
 
I had a C class that would do that if it wasn't on level ground. Water from the sinks would fill the shower. Once I moved it to a level surface it would drain properly.
 
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