Help: Shower filling up with Kitchen sink water. How?

[Wayfinder]

Has anyone had their shower backup with water after running water in the kitchen sink?

The grey tank is empty, for sure. I am being told they have dumped their tanks.

Any way a leak from the water system could fill up the grey tank?

Shower gate valve is open I am told.

Seems like a clog somewhere.

Asking for a friend.

 

UPDATE: I just received word from her that her indicator for the grey tank is NOW showing 100%.  

But question still stands, just in case. Is there any way a grey tank could fill up with a friend water tank/line leak? 

I cannot think of a way, there should be no fresh connections to grey, right?  She travels with no water in fresh tank as well. 

 

Edited Tuesday at 04:24 PM by Wayfinder
update

[Wayfinder]

At least my first suggestion to her was that her tanks were full. But she was sure they were not.  LOL

[Mike and Carol]

If her gray tank is full then water draining from the kitchen sink could cause backed up water to flow back into the bathroom and out of the shower drain.  I don’t know of any connection between the gray tank and the fresh water system.  Gray tank inputs are from the kitchen and the bathroom, one each.  No fresh water inputs.  Mike

[Wayfinder]

7 minutes ago, Mike and Carol said:

  I don’t know of any connection between the gray tank and the fresh water system.  Gray tank inputs are from the kitchen and the bathroom, one each.  No fresh water inputs.  Mike

That's exactly what I was thinking, but I can never know everything. Thanks for the confirmation.

[Ray Kimsey]

Seems the problem was that the gray tank was full but for others: On older trailers (mine for example, a 2020) you might have a manual gray tank valve. Pulled out is open allowing the gray tank to vent as water from kitchen sink flows in.  If it is closed (pushed in) then water could back up into the shower drain if you run a lot of water in the sink. Also, if you leave the valve open while driving down the road, then gray water could slosh up onto the floor from the shower drain. 

[Wayfinder]

Yeah, I've figured out once that I did not open it when my feet were getting wet while at the bathroom sink.  😜

[Townesw]

Are they sure it’s kitchen water? Are they adding water to the black tank using the No Fuss Flush fitting? If they are flushing the black tank and have let it get too full and the shower drain valve is closed the water from the black tank can back up in the black tank vent and flow over into the sink drain and rise up through the shower drain and fill the shower pan and could actually overflow the pan and flood the trailer floor. 
 

Do not rely on the tank level display when diagnosing water level and drainage problems, or any other time really. 

I apologize for the “ands” and the run-on sentence.

Bill

Edited Tuesday at 06:34 PM by Townesw

[Wayfinder]

42 minutes ago, Townesw said:

Are they sure it’s kitchen water? Are they adding water to the black tank using the No Fuss Flush fitting? If they are flushing the black tank and have let it get too full and the shower drain valve is closed the water from the black tank can back up in the black tank vent and flow over into the sink drain and rise up through the shower drain and fill the shower pan and could actually overflow the pan and flood the trailer floor. 
 

Do not rely on the tank level display when diagnosing water level and drainage problems, or any other time really. 
 

Bill

 

All good questions and statements Bill. None should apply to her situation as I understand it. Some how I think she forgot to drain grey tank, or some how left water on trying to get the water to heat up.  

Where is the location of your drains & vents?  My old rig is not like that as I'm aware of.  UPDATE: OH, THIS MUST BE UNDER THE BATHROOM SINK. I have not been under mine yet.

Also, here toilet would overflow when she opened the foot valve if the black tank got that full.  She's never used the flush out yet. I'll be showing her that and other things in a couple weeks (training).

Edited Tuesday at 07:15 PM by Wayfinder

[jd1923]

Is the trailer level? When we park, we level and keep the front 1/2"+ higher. This allows full usage of the FWT and our heads are just higher than our feet in bed.

If the front is a couple inches low, water from the kitchen drain would flow forward. 

[theOrca]

23 hours ago, jd1923 said:

Is the trailer level? When we park, we level and keep the front 1/2"+ higher. This allows full usage of the FWT and our heads are just higher than our feet in bed.

If the front is a couple inches low, water from the kitchen drain would flow forward. 

That also lets you actually use the last 7 gallons of fresh water...