Water Leak from Rain

Yoshi_TAB

Hi,

Out traveling and have observed a water leak while raining coming from  the exterior of bathroom corner wall.  I am certain it is from rain as it stops/starts with rain.  Water is clear and not blue/green. I inspected where the electrical meets the shower walk and can not see where it starts.  It runs mostly out the exterior corner of bathroom, like it’s under the shower .  

Any suggestions of where/how to look on exterior.  We are planned to be out for 4 more weeks. This is a ‘21 320.  Thank you

Basil48192

@Yoshi_TAB
I would check the seal on the exterior door to your toilet cassette.  Water collecting in the lower part of the cassette cavity can leak out just as shown in your photo.  
When I first had my 2021 320S, I had an issue with the cassette not sealing properly (due to that useless plate beneath the cassette...but don't get me started 😂), while testing it with clean water, I noticed that water would accumulate in the lower parts of that space and migrate out into the cabin.  I hope this helps!

Sharon_is_SAM

Not sure not sure if this helps, but here is a photo of an earlier model after removing the shower pan.  

Sharon_is_SAM

Did the water collect while traveling down the road or while stationary?  

Yoshi_TAB

Tks @Basil48192 and @Sharon_is_SAM

We’ve been out for 3 weeks and this was the first rain.  It definitely stopped and started with the rain while stationary.

I was looking through some FB posts and saw a picture of water infiltration in the same spot on a ‘21.  One was due to the cassette door as mentioned above and the other was dry rotted sealant around the gray water vent on the side.  

@Basil48192; did the seal become misaligned or was it damaged ?

It has not leaked since it stopped raining .  Our next site has water hook ups.  When we get there I’ll test with a water hose on the outside at both locations.  

Thank you

Basil48192

@Yoshi_TAB
I apologize....I was trying to word it properly so I didn't confuse the issue.  The source of my leak was flush water because the seal on top of the cassette didn't seal properly against the flange on the bottom side of the toilet.  The seal was not damaged.  The root cause was that the cover plate on the sump below the cassette prevented the cassette from securely latching in place.
In your case, I'm guessing that the water is collecting in the same area and following a similar path...but the source is rainwater getting past the access door seal and/or bad caulking around the access door flange.  

Yoshi_TAB

Hi,

Want to post an update if anyone else discovers such a leak.  I’ve narrowed it down to either the exterior gray tank vent or outside cassette door seal with it most likely being the gray tank vent.  We are still out traveling but in a heavy rain today  the leak has stopped .  I was able to caulk around the gray tank vent  before the rain.  For now,  since we are still out traveling , just before the rain , I placed painters tape around the cassette door to seal it.  We have not been at a water site for a while so I can not use a hose to confirm if it’s the cassette door or not, but leak appeared to originate  inside around the black vent pipe that you can just see beyond the electrical area  so I suspect the exterior gray tank vent (shown with cover off).  When we are at a water site, I’ll spray the cassette door from the top to confirm for sure .