Scott / 2019 T@B 400 "C@lypso" / 2015 Chevrolet Tahoe LTZ / Northern Illinois
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qhumberd
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Tab 400 Bathroom Fold-down Sink Not Draining - Resolved
marleecamps
Member Posts: 179
Posting this in case it helps anyone else at some point. While dewinterizing my 2021 Tab 400, I noticed that the bathroom sink was not draining properly - water was flowing out of the crevice below the sink portion. Pulled off the front panel expecting to see a loose fitting but all looked fine. Then took a closer look at the crevice with flashlight in hand and noticed that the drain was completely covered with "gunk". Guessing it's four years' worth of toothpaste debris, etc. Ick!


But, a relatively easy fix. Managed to clear enough to confirm that this was the cause. Now, I'm just searching for a cleaning tool skinny and long enough to fit into that slot and get the rest of it cleared away.
Another item to add to my annual maintenance list - as well as note to self to not be so stingy with rinsing water.


But, a relatively easy fix. Managed to clear enough to confirm that this was the cause. Now, I'm just searching for a cleaning tool skinny and long enough to fit into that slot and get the rest of it cleared away.
Another item to add to my annual maintenance list - as well as note to self to not be so stingy with rinsing water.
--Marlee
2021 Tab400 Boondock; TV 2025 Jeep Grand Cherokee Limited; Minnesota
2021 Tab400 Boondock; TV 2025 Jeep Grand Cherokee Limited; Minnesota
Comments
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Thanks for sharing the tip. I will have to check our 400. I have never looked that closely at our sink. Does the sink drain empty into that second drain you mention that was clogged? And does that second drain also capture any water left in the sink when tipped up? Thanks again.
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Yes, there is a small open-ended hose from the sink drain that empties into the area in the crevice. You can see it when you tip the sink up. The second drain, which you can see in the second photo, goes into the gray tank. And yes, any water in the sink itself would empty into that crevice area when tipped upright. The crevice area is probably an inch deep.
Now that I have it all squeaky clean again, all is well. Sprayed some Dawn/vinegar solution to loosen everything up and then scraped with a rubber scraper covered with paper towels. Rinsed with the shower wand. Will become a step in my season end storage prep process.--Marlee
2021 Tab400 Boondock; TV 2025 Jeep Grand Cherokee Limited; Minnesota -
@marleecamps I am not 100% sure I agree with your assessment. When I looked at our sink, I see the secondary drain that is there to catch water from the sink when the sink is flipped up. I also see a black flexible line on the left side hinge area that I believe is the primary sink drain. I found no outlet in the back of the sink unit itself that would allow water from the sink drain to get to the secondary drain. I may be off base and would welcome what others know. In any event, I am happy your sink drain is working properly now.
Scott / 2019 T@B 400 "C@lypso" / 2015 Chevrolet Tahoe LTZ / Northern Illinois -
You could be right. I am no plumber, nor do I have any desire to be. What I can say is that when that drain was covered with goo, the sink did not drain when in the down position - all the water ran over the lip of the crevice area and into the floor drain. Once I cleared away the goo, the sink now drains properly.
In the first photo, you can see the black drain hose attached to the drain in the crevice area. Certainly possible there is another drain hose attached to the actual sink drain, but I have the front panel reattached so can't readily check. There is also a small short rubber hose at the very bottom center when the sink is in the upright position (rear of the sink itself) - you cannot see it in the photo as it blends in with the slimy goo. My assumption was that this is where the sink water drained. We also might have different setups as we have different model years.--Marlee
2021 Tab400 Boondock; TV 2025 Jeep Grand Cherokee Limited; Minnesota -
OK, my curiosity got the better of me and I conducted a very simple, non-scientific experiment. First, here is a closeup of the short hose I mentioned - at the rear of the sink itself and visible when in the upright position.

Then I stuffed a cotton ball into the tube. Placed the sink in the down position and poured a cup or two of water into the sink basin. Nothing drained. Tipped the sink back up, which drained that water, removed the cotton ball and then repeated the exercise. This time the water drained immediately.
So at least on my 2021 Tab400, that secondary drain seems to be the primary pathway for water to flow through to the gray tank from the sink, whether the sink is up or down. And now I know I need to keep it clean!
--Marlee
2021 Tab400 Boondock; TV 2025 Jeep Grand Cherokee Limited; Minnesota -
Yep, it is a difference in model years. We have a 2019 T@B 400. I tried to take a picture of the same area you just posted:
No drain port hose for ours.I also took a picture of the overall sink assembly:
I think you have a different size/style fold-down sink.Thanks for going further into your explanation!Scott / 2019 T@B 400 "C@lypso" / 2015 Chevrolet Tahoe LTZ / Northern Illinois -
Yeah, my sink looks like this.
--Marlee
2021 Tab400 Boondock; TV 2025 Jeep Grand Cherokee Limited; Minnesota -
Thanks for this clarification. I am glad to see NuCamp improved the plumbing somewhat compared to the 2019 era round sink.marleecamps said:Yeah, my sink looks like this.
I had to remove ours as the round drain in the center of our sink disconnected from the corrugated drain and was impossible to reconnect.
The plumbing of the round sink shows a corrugated drain running from the bowl of the sink, and a secondary drain at the back, to drain when the sink is folded.
The length of the corrugated drain was a set up for clogging, and I could not figure an easy way to clean it out, so we covered the area and just have more space. The 2021 and newer models have a better sink design.2019 T@B400 Boondock Lite "Todd"2016 Toyota Tundra 5.7 Crew Cab -
@qhumbred, thank you for the pictures! As they say, a picture is worth a thousand words and further explains the differences between the two sink configurations.
Scott / 2019 T@B 400 "C@lypso" / 2015 Chevrolet Tahoe LTZ / Northern Illinois -
I solved the bathroom sink drain issue in my 2019 T@B400...
2019 T@B400
TV: 2017 Nissan Frontier SV 4X4
Southern California
Full-timer since 2019 -
Scott / 2019 T@B 400 "C@lypso" / 2015 Chevrolet Tahoe LTZ / Northern Illinois
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Nice to have some extra towel bars, too.