Black Tank Leak

We have a 2014 Landmark Key Largo and have noticed a sewage smell for quite some time. Primarily when running the Stove Fan or the Fantastic Fan. Today I noticed water in the Cargo Hold and found that the Backflow Valve on the Sewer Back Flush Hose was leaking.

However, when I had the wall off to check for wetness in the under carriage I noticed the sewage smell. I looked in on top of the black tank and it is covered in areas of brown waste:-mad: Has anyone experienced this, and what could be causing it?

Other than a leaking toilet seal which is directly over the tank, a cracked tank, unglued tank vent fitting.... If it is not the toilet seal you need to drain the tank and clean it up using bleach. Flush the tank well and then fill with bleach water with red food dye. Watch for where the water starts to seep out. Or take it in to be diagnosed and repaired by your dealer or independent RV repair business. Note that if it is clean prior to bringing it in, it will not cost you nearly as much as a major poop clean up job, and remember all cleanup is hazardous waste. So bag it all and bleach it.

Any chance you might have overfilled the tank while adding water through the black tank flush? If that happens, it's possible to force black water out in several places.

When checking, there is no sign of leakage or wetness above the tank. I inspected the Large Black Pipe coming from the stool and it was totally clean. I also wiggled it to see if it was loose at the tank end, but it was tight. I am going back in today to see what else I can find.

That is a good question, but I am very conscious of the issues that could be caused by the pressure from the flush valve. I have always opened the Black Tank Drain Valve prior to applying water pressure. Additionally, the top of the tank still has wetness in several spots. I assume that it should be dry unless it is coming from another source. No apparent leaks from the Stool Down-Pipe either at the stool end or the tank connection.

I used my cell and took pictures up under the flooring above the tank to see if I could tell anything. Toward the back side (opposite the entry door), there appears to be a black rubber plug with a short strap on it on top of the Black Tank. Do you know if that is part of it or just something laying there?

nice! At that point you may have to take the chloroplast down and clean everything out before you can find the source.

LivingRDream said:

When checking, there is no sign of leakage or wetness above the tank. I inspected the Large Black Pipe coming from the stool and it was totally clean. I also wiggled it to see if it was loose at the tank end, but it was tight. I am going back in today to see what else I can find.

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Yah. I forgot that if you over fill the tank, the brown trout and wrapping paper can spray all over the roof or out of the toilet. If it were to happen to me, my choice would be the roof. If the seal around the vent pipe on the roof is open, it could flow down the pipe onto the top of the tank. Red food dye in the water makes it easy to spot a leak and with bleach it should no longer be hazardous. The human eyes detect red the best. With a cracked tank or flange, the pressure of the sprayer could force the fun stuff out. It may also take a full or near full black water tank to show where the leak is coming from.

LivingRDream said:

That is a good question, but I am very conscious of the issues that could be caused by the pressure from the flush valve. I have always opened the Black Tank Drain Valve prior to applying water pressure. Additionally, the top of the tank still has wetness in several spots. I assume that it should be dry unless it is coming from another source. No apparent leaks from the Stool Down-Pipe either at the stool end or the tank connection.

I used my cell and took pictures up under the flooring above the tank to see if I could tell anything. Toward the back side (opposite the entry door), there appears to be a black rubber plug with a short strap on it on top of the Black Tank. Do you know if that is part of it or just something laying there?
View attachment 47735View attachment 47736

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Found out that the camera magnified it in my mind, that was just the end of a tie wrap. Feel really stupid right now but answered my own question. Unfortunately the leak not yet located.

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mlpeloquin said:

Yah. I forgot that if you over fill the tank, the brown trout and wrapping paper can spray all over the roof or out of the toilet. If it were to happen to me, my choice would be the roof. If the seal around the vent pipe on the roof is open, it could flow down the pipe onto the top of the tank. Red food dye in the water makes it easy to spot a leak and with bleach it should no longer be hazardous. The human eyes detect red the best. With a cracked tank or flange, the pressure of the sprayer could force the fun stuff out. It may also take a full or near full black water tank to show where the leak is coming from.

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Thank you, I will see what I can figure out.

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Bones said:

nice! At that point you may have to take the chloroplast down and clean everything out before you can find the source.

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Thank you, I will drop the bottom and replace insulation for sure. Was hoping to find leak first. Still trying On my way! Things at this point.

After putting 40 Gallons of water in the Black Tank through the Stool using a five-gallon bucket, I watched as more water was added until I saw a leak. It is coming out around the flange where the Stool Down Pipe mounts to the top of the tank.

Now the fun part. Dropping the underbelly and replacing the insulation. Thank you to all for your suggestions!!!

Boy that's one problem I hope I never have.

LivingRDream said:

After putting 40 Gallons of water in the Black Tank through the Stool using a five-gallon bucket, I watched as more water was added until I saw a leak. It is coming out around the flange where the Stool Down Pipe mounts to the top of the tank.

Now the fun part. Dropping the underbelly and replacing the insulation. Thank you to all for your suggestions!!!

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I hope it can be removed and resealed properly. Don't think I would trust an external sealing solution. You might try and find out if the flange is on the tank from the supplier. If so it was a manufacturing defect from the tank supplier. If not, it would be a Heartland assembly problem. If the flange was properly glued, this would not be an issue.

I have an appointment with a dealer to drop and seal tank. I will post the outcome.

Please, no more of those pictures after supper. Ldo

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Update:
I contacted Heartland and took the unit to Camping World Lake Park, GA. Since it was under warranty, Heartland approved the repair. CW technician tried first to seal the threads around the connection on top of the tank and it still leaked. He then used silicone and sealed it and water tested it again without any further issues.

CW was amazing. They have a campground adjacent to the location and allowed us to stay for free. They did a great job and no more smell They not only replaced the insulation, but the foil and the plastic underbelly sheeting. The process took longer than I would have preferred, but it was just because of the procedure to estimate it, get approval from heartland, get the parts, and perform the repair. After the repair was complete, the technician took me into the shop and explained everything he did and why he did it (had a few other minor issues addressed while there). All total it took around three weeks. We were very happy that CW took care of us the way they did, especially since we did not purchase it from them.

Thanks for all of the comments and suggestion.