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Why is Water Backing up Into My RV's Bathtub/Shower Drain?

by Mark G.
(The Woodlands, Tx)

Why is Water Backing up Into My RV's Bathtub/Shower Drain?

Why is Water Backing up Into My RV's Bathtub/Shower Drain?

I have a new 2014 Gulfstream Kingsport 26.5 We were only on our second weekend outing and we noticed Saturday night that the bathtub drain seemed clogged (was running water into the bathroom sink and it came back up through the tub drain) My wife has long hair but I can't imagine that its getting clogged after only 3 showers?

Tried some baking soda and white vinegar and it seemed to clear a bit and drain... After towing it home to storage and checking it again, it wasn't draining.. Going to call The dealer that I bought it from this AM and ask some questions but I thought I would post here too..

MDG in the Woodlands

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ANSWER: Hi Mark thanks for submitting your question on our Ask An RV Question Page

I think that I am going to be the bearer of good news. I do not believe that your new Gulf Stream travel trailer bathtub drain is clogged I think that you need to dump your Travel Trailers gray water holding tank. The first thing that you should check is the monitor panel in the RV and look at the gray water holding tank level and I am pretty sure that you will see that it needs to be dumped (can't blame your wife's long hair on this one).

The fact that you said that you had taken 3 showers and never mentioned emptying the gray water tank is a pretty good indicator that your gray water holding tank is full and should be dumped. The gray water holding tank on your particular RV holds a total of 37 gallons of waste water and it will fill up quite quickly especially if you choose to take long showers.

You also mentioned that the water started coming up the bathtub drain when you were running more water in the bathroom sink; that also indicates that your holding tank is full. When you were running the water in the sink there was no more room in the tank so the water started to come out of the lowest drain in the gray water system which
in most cases will be the bathtub or shower drain in an RV.

by the way do not feel bad about having this happen to you, because I can guarantee that you are not the Lone Ranger in having this happen. It has happened to me and I guarantee that it has happened to a lot of other RVers who may not be as willing to admit it.

A good rule of thumb when at a campground is to make it a habit to check the Gray and Black water tank levels on a daily basis and dump them when they reach the 3/4 full mark. Also a reminder here: even though you are hooked up to a sewer system when at a campground you should not leave the dump valves open as letting the water drain out and not the heavier waste solids can cause problems with your waste holding tanks in the future.

Another good rule of thumb is to dump your waste holding tanks before leaving a campground so that you have clean tanks and less weight to haul around.

I hope that this information has been helpful to you.

Do you have any suggestions or comments on this topic? You can add them to this page by clicking on the "Click Here To Post Comments" link located near the bottom of this page.

Happy RVing

RVing Al
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Comments for Why is Water Backing up Into My RV's Bathtub/Shower Drain?

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bathtub drain
by: cdc43

I was just finishing a shower (95% done) and approx 1 inch of water remained in drain. Sometime overnight, it did drain. I did the following to investigate. Water drains from sinks to grey water tank.

1. back flushed grey tank
2. checked vent stack by dropping a plumbob from roof to tank bottom - clear to bottom
3. removed and cleaned tub trap
4. snaked the drain from trap to grey tank
5. flushed vent stack from roof with hose - water went into tub???

Please any other ideas.


plumming backing up water in shower
by: cynthia

I have the same problem with the water backing up in the shower when doing dishes and both drain out valvea are open and empyed out where is the clog help

i dont assume
by: thinking

the vent on roof could be plugged, even just partially or too small. So when water drains in say the bathtub it pushes air down ahead of water and that air needs to go somewhere. That air then pushes back up another drain if it cant all go up vent to roof. When it pushes back up say the sink drain it pushes all the water in the trap ( the u in the drain pipe ).

RV manufacturers are not known for quality workmanship or logical designs. Its all about making it cheap and light weight. It is very possible they left scrap material or garbage in vent pipe and it is also possible the pipe was designed too small. There is also other ways it can get plugged such as bugs or over filling tanks and causing something to go up vent pipe.

Go up on roof and you can remove cap on vent pipe. Use logic form there to see if it is plugged. The line should be at least 1-1/2" inside diameter. Any less and it could be a design flaw.

Why is Water Backing up Into My RV's Bathtub/Shower Drain?
by: Mark G

That was the first thing I did wasa empty the gray tank.... it still wont drain...

Yes, don't fell bad.
by: Anonymous

When you have lived your whole life in a stick house it can be hard to wrap your head around things required for a rig that happen automatically in a house. Be glad you first learning experience was with gray water. For many of us, it was with black water. (Mine was on the importance of making sure the hose connector is properly seated each and every time you dump and open the grey water first, just in case.)

Note From RVing Al: You may want to read our article How Not To Dump Your RV Holding Tanks to find out how much worse it could have actually been. :-)

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