Black Tank Won't Drain Properly

I'm having serious drainage issues with my black tank. A mobile RV repairperson came and cleaned out massive amounts of sludge but that didn't solve the problem because the sludge continues to build up as time passes. The RV mobile tech told me this happens because the tanks on Heartland products have a tendency to "bow" downward as they fill and the weight increases. He told me there is no solution to this issue. I refuse to believe this to be true. I have contacted Mike Moreland, Regional Mgr. for Heartland with no results thus far. Can anyone offer any advice? Has anyone else encountered this problem and what did you do to solve it. I hate to think that I own a fifth wheel that will have chronic black tank drainage issues with the incumbent smell. Thanks in advance for any help provided.
 

LBR

Well-known member
Judging by your description, I would be apt to think the cutout for your black tank drainhole may have been left inside and could be partially blocking the outlet at times.
 

danemayer

Well-known member
You may have a slow leak at the black tank gate valve, allowing the water to drain out the sewer outlet, leaving a pile of solids behind. This can happen if paper or waste gets trapped in the gate valve track, preventing it from closing completely. One of the symptoms is that when you go to dump the black tank, very little water comes out.

For more info on this, take a look at pages 17-21 on our owner-written Water Systems user guide in this folder.
 

JohnDar

Prolifically Gabby Member
Your RV tech is guessing. My rig is almost 10 years old and I can flush it to clear water. Sure, the sensors are for crap, but I don’t have a poop pyramid and it doesn’t stink. Do you flush the toilet with a bowl full of water or are you “conserving” so you don’t have to dump as often?


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Your RV tech is guessing. My rig is almost 10 years old and I can flush it to clear water. Sure, the sensors are for crap, but I don’t have a poop pyramid and it doesn’t stink. Do you flush the toilet with a bowl full of water or are you “conserving” so you don’t have to dump as often?


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We do flush with plenty of water so I don't think lack of water is the issue. Thank you for your reply.

- - - Updated - - -

Do you normally leave your black tank valve open or closed when your hooked up ??

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We leave it closed. The only way I can get it to even minimally drain is to open the valve when the tank is full, then fill up the tank and flush and I have to do it several times and there is still "junk" in the drain. I did see when the mobile repair tech cleaned out the tank and there was just tons of paper and waste that hadn't drained.

- - - Updated - - -

Judging by your description, I would be apt to think the cutout for your black tank drainhole may have been left inside and could be partially blocking the outlet at times.
The cutout? Not sure what you're talking about here but I can mention this when I take it to an RV repair place. Thank you!
 

rhodies1

Well-known member
I was having the same issue you describe with my BH,finally one day at the CG it wouldn’t dump at all,only a minimal amount of liquid dumped.Had to take unit home and address finally.After many times of running snake from outdoors up the sewer line into the tank,using rubber boots and a 5 gallon pail to catch sewage.....finally dislodged a piece of round shaped plywood,part of the floor cutout when toilet was installed.......not sure you have this issue but it maybe a cause.
As well, you can drop the underbelly coroplast and install a couple pcs of flat bar across the channels that hold up your tank,if the tank is bowed down in the middle ,this will level the tank belly and help drain,if your rv repair man is correct and your tank belly is bowed downward allowing sewage to remain and not drain.
Chances are this is a relatively easy fix.
 

LBR

Well-known member
The cutout? Not sure what you're talking about here but I can mention this when I take it to an RV repair place. Thank you!

It has been reported by several members that when the hole is cut into tank for the outlet, the plastic plug can accidentally drop into the tank, rather than it getting pulled out and thrown away. This plug can then obstruct the tank's outlet port some and cause a poor emptying of the tank scenario, such as you have.
 

danemayer

Well-known member
Has anyone actually found a cutout blocking their black tank outlet on a trailer built in the past 5 years? I see people mention it as a possibility, but I don't think I've seen an actual case in quite a few years.
 

JohnDar

Prolifically Gabby Member
The tank (at least mine) is supported by metal straps. As the tank fills, the bottom does flex downward with the weight. It returns to a flatter state when the tank drains. Another question is are you using the black tank flush to help push waste out as you drain the tank? This is the one in the UDC, not an attachment on the outside sewer outlet. On occasion, I've had waste block the tank opening, especially if the toilet had been used just before dumping. In that case, either using the tank flush or the back flush adapter on the sewer connection has moved it and allowed the tank to continue to drain properly. If you try to do it with just the tank flush, keep an eye on how much water you're adding. If it doesn't start to flow out fairly quickly, you may need to use the back flush to avoid overfilling the tank. Once you do get it to drain out, continue running the tank flush for several minutes until it run clear (you'll need a clear sewer adapter fitting with a back flush adapter on it). With mine, when I'm satisfied that it's "all ashore that's going ashore," I add 5 to 7 gallons of water back into it with the valve closed, along with the chemical of choice. Never start using a black tank with no water in it.

Another question is what tank additive are you using in the black tank. While some may not like using chemicals, they do work to digest the waste. Some seem to work better than others.

One last thought is the vent pipe from the tank to the roof. If it's obstructed, the tank may not drain properly, either. As the water flows out, air has to come back in. Since the toilet is closed, the vent is the only way. That pipe has been known to be a problem for some. You can remove the cap on the roof and drop a weighted line down it, or as some have done, run a hose stream down it. Be careful not to splash around it or you might get water under the roof. If you run a hose down it, have the tank valve open.

Finding construction debris in the tank is not out of the question. I have not found it on this trailer, but our previous TT (another brand) had broken pieces of wood and a spade bit come out into a bucket.

I don't see where you've specified what model trailer you have. That might also be useful. Do not think that replies are being smart-axxy since we're trying to figure out a solution to your problem long distance based only on what we read here and what we've experienced with our own rigs.
 

mlpeloquin

Well-known member
I believe by law that all tank treatments are enzyme based. No chemicals like formaldehyde based ones years ago. They were outlawed. We have been using Happy Camper and Costco toilet paper and have not had a problem since. Only one time I could not get the black tank to drain and I remembered the advice in the forum from another member. I have an external valve at the end of the sewer line. I closed it. Opened the two gray water valves to hep back flush the black tank opening. Closed the gray water valves and opened the external valve. The black tank flushed perfectly. I may or may not have a round piece floating around the tank, but it did clear the obstruction. Then we switched to Happy camper and Costco toilet paper have not had a problem since. Prior to Happy Camper, we only used RV TP stuff.
 

JohnDar

Prolifically Gabby Member
I didn't say anything about using formaldehyde (I used to work with industrial strength stuff years ago). The stuff on the store shelf or online is enzyme-based. As for TP, we've been using Angel Soft 2-ply for years without a problem. With the tank flush, I start it running before the tank has finished draining, when the flow starts to slow down.
 
I believe by law that all tank treatments are enzyme based. No chemicals like formaldehyde based ones years ago. They were outlawed. We have been using Happy Camper and Costco toilet paper and have not had a problem since. Only one time I could not get the black tank to drain and I remembered the advice in the forum from another member. I have an external valve at the end of the sewer line. I closed it. Opened the two gray water valves to hep back flush the black tank opening. Closed the gray water valves and opened the external valve. The black tank flushed perfectly. I may or may not have a round piece floating around the tank, but it did clear the obstruction. Then we switched to Happy camper and Costco toilet paper have not had a problem since. Prior to Happy Camper, we only used RV TP stuff.

Thank you for the help advice.

- - - Updated - - -

The tank (at least mine) is supported by metal straps. As the tank fills, the bottom does flex downward with the weight. It returns to a flatter state when the tank drains. Another question is are you using the black tank flush to help push waste out as you drain the tank? This is the one in the UDC, not an attachment on the outside sewer outlet. On occasion, I've had waste block the tank opening, especially if the toilet had been used just before dumping. In that case, either using the tank flush or the back flush adapter on the sewer connection has moved it and allowed the tank to continue to drain properly. If you try to do it with just the tank flush, keep an eye on how much water you're adding. If it doesn't start to flow out fairly quickly, you may need to use the back flush to avoid overfilling the tank. Once you do get it to drain out, continue running the tank flush for several minutes until it run clear (you'll need a clear sewer adapter fitting with a back flush adapter on it). With mine, when I'm satisfied that it's "all ashore that's going ashore," I add 5 to 7 gallons of water back into it with the valve closed, along with the chemical of choice. Never start using a black tank with no water in it.

Another question is what tank additive are you using in the black tank. While some may not like using chemicals, they do work to digest the waste. Some seem to work better than others.

One last thought is the vent pipe from the tank to the roof. If it's obstructed, the tank may not drain properly, either. As the water flows out, air has to come back in. Since the toilet is closed, the vent is the only way. That pipe has been known to be a problem for some. You can remove the cap on the roof and drop a weighted line down it, or as some have done, run a hose stream down it. Be careful not to splash around it or you might get water under the roof. If you run a hose down it, have the tank valve open.

Finding construction debris in the tank is not out of the question. I have not found it on this trailer, but our previous TT (another brand) had broken pieces of wood and a spade bit come out into a bucket.

I don't see where you've specified what model trailer you have. That might also be useful. Do not think that replies are being smart-axxy since we're trying to figure out a solution to your problem long distance based only on what we read here and what we've experienced with our own rigs.

Thank you. Great advice here. I have a 2017.5 Heartland Bighorn Model 3890SS

- - - Updated - - -

I was having the same issue you describe with my BH,finally one day at the CG it wouldn’t dump at all,only a minimal amount of liquid dumped.Had to take unit home and address finally.After many times of running snake from outdoors up the sewer line into the tank,using rubber boots and a 5 gallon pail to catch sewage.....finally dislodged a piece of round shaped plywood,part of the floor cutout when toilet was installed.......not sure you have this issue but it maybe a cause.
As well, you can drop the underbelly coroplast and install a couple pcs of flat bar across the channels that hold up your tank,if the tank is bowed down in the middle ,this will level the tank belly and help drain,if your rv repair man is correct and your tank belly is bowed downward allowing sewage to remain and not drain.
Chances are this is a relatively easy fix.

Thank you!
 

Fox

Well-known member
Has anyone actually found a cutout blocking their black tank outlet on a trailer built in the past 5 years? I see people mention it as a possibility, but I don't think I've seen an actual case in quite a few years.

On my one year old/ preowned Bighorn when I flushed (2 weeks ago) a crescent moon shaped piece of black plastic came out. I believed it to be a piece of the tank - it surely wasn't a GI Joe figure.

I've also subsequently found that the outside shower only extends about one foot, I'm guessing its pinched against something behind the wall it disappears into.
 

DaveTyler

Well-known member
One thing we do because of previous stops is do not put any paper of any brand inside the toilet. Explain to guest also if you ever have to pull a toilet and stick your arm down to your neck,you will not use paper or go use the campground toilet. We use a trash bag with wal mart sacks. In addition to all mentioned. Good luck!!


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BLR

Well-known member
One thing we do because of previous stops is do not put any paper of any brand inside the toilet. Explain to guest also if you ever have to pull a toilet and stick your arm down to your neck,you will not use paper or go use the campground toilet. We use a trash bag with wal mart sacks. In addition to all mentioned. Good luck!!


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Why have a toilet??.. just go outside.
35 years of RVing and have never had a problem with any of our toilets or drains

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jerryjay11

Well-known member
One thing we do because of previous stops is do not put any paper of any brand inside the toilet. Explain to guest also if you ever have to pull a toilet and stick your arm down to your neck,you will not use paper or go use the campground toilet. We use a trash bag with wal mart sacks. In addition to all mentioned. Good luck!!


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YUCK! Who's responsible to dump those bags and where?
 

JohnD

Moved on to the next thing...
The backflush is a method I was taught when I was a kid (back in the 70's) and I always do this when draining the tanks.

It will not only loosen stuff on the bottom of the tank, but will also knock loose any blockage in the black tank drain pipe.

First off, you'll need to get one of these (every RV should have one no matter what) - click here: https://www.campingworld.com/twist-on-valve

Make sure it is the twist on valve...

Here is mine:

ProwlerDrainCap-P3290012.jpg


When I drain the black tank I start running water through the built-in flush right after I open the black tank drain valve and let it run the whole time.

Once the black tank slows to a trickle (with the flush still running), I then leave the black valve open, but close the Valterra Twist On Valve, then open the gray tank valve allowing the gray water to flow back into the black tank.

You can hear it bubbling, but I put my hand on the black tank drain pipe and can feel the bubbling...and when it stops bubbling, I close the gray tank drain and open the twist on valve.

With the clear fitting, I can usually see that the water was running clear before doing the backflush, but the first backflush will look like I just pulled the drain for the first time as it always loosens up a bunch of crud that the built-in flush just doesn't get loose.

I also like to fill the toilet full and flush a few times while the tank is draining as I feel that the force of the water from the toilet flush dropping directly to the bottom of the tank will help dislodge any buildup directly under the toilet.

Anyway, I'll do the back flush 5-10 times until the water coming out is almost clear (gray water looks 'gray', not clear).

When done with the black tank, then use the rest of the gray water to clear out the drain hose...but will still need to rinse that out with clean water as well.

I also use the orange flavored TST tablets (I call them 'Toilet Mints') in the tank.

Once the tank is cleaned and the black drain closed, I'll fill the toilet all the way full with water twice, then fill the toilet one more time and toss an 'orange mint' in there and let it desolve, then flush that down as a primer for the next use, or for storage if I plan on using it again soon.

My Prowler has been parked in storage in the southern Arizona heat for five weeks and that solution is in it right now.

When I checked on it the other day there was no odor coming from the tank (daily inside camper temps of 135-140 degrees).

Taking it out this coming weekend for a trip to Sedona and I'll bet all is OK!
 

DaveTyler

Well-known member
Jerryjay, I take responsibility to take the trash out. Only paper in the bag. If you ever have the problem, you will gladly take out the trash!! Believe me. Experience.


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