RV Black Water Tank Problems – What Can You Do?

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As a full time RVer, we deal with a lot of crap year-round!  And I am not talking about life situations here.  I am referring to fecal matter.  If you use your RV often, RV black water tank problems will arise!  There are easy methods to “clear things up,” but simple RV black water tank maintenance using water and an RV black tank cleaning wand will avoid any unexpected issues!

Avoiding RV Black Water Tank Problems

There are a few easy things you can do on a regular basis to keep things flowing and also to keep your tank sensors showing the correct tank levels. These might seem very basic, but I talk to many RVers who do not do these things and their problems because of it.  So here are just a few ideas.  We will cover the basics first.

Use lots of water when flushing!  I know this is hard to do when boondocking, but I fill the bowl with water for each flush of a number two event.  LOL!  For just liquids only, not as much.  You want to be sure you have enough liquids in the tank to dissolve the solids and allow them to flush out when emptying the RV black water tank completely.

Never leave the RV black water tank gate valve open!!  Empty the tank when needed and keep the gate valve closed till it is full again!!  If you are traveling a lot, when the tank is half full, add water to fill the tank and then dump it.  After all, water is weight, and carrying hundreds of extra pounds of liquids should be avoided on certain RVs! This is my opinion, but it is based on years of RV travel.

Use septic-safe toilet paper!  You want to use TP that will dissolve easily in water.  You can perform a simple test independently to see if your choice of TP dissolves completely.  Take a piece of the TP, put it in a glass of water, and let it sit.  It should dissolve. If not, don’t use that brand.  Pam and I buy single-ply septic-safe TP, and that seems to work fine.  If you need super plush, soft, and scented TP, I suggest you not throw it in the RV black water tank but into a sealed waste basket.rv black water tank

Only empty the RV black water tank when it is full!  As mentioned earlier, when emptying the tank when it is not full, it can lead to problems.  You will not get a good flush out unless you have a lot of liquid in the tank.  

While using your RV black water tank, depending on how often you need to dump it, solids will settle to the bottom of the tank.  If it sits there in liquid for a week, the only way to be sure to get the stuff to flow out is to have a lot of water pushing it out the RV black water tank pipe at the bottom of the tank.rv black water tank

Be careful what chemicals you throw in the RV black water tank!!  I just recently was told a story by an RV full-timing friend of mine.  I will share it here to make a point about this one.  She was told that the little dishwasher packets they sell these days work great in the RV black water tank.  

So, she put a few in before hitting the road, thinking that as she drove, they would help clean and sanitize the tank.  She left the RV for a week while on a trip and returned to it and added one of the normal RV tank treatment packets to the tank, thinking that she had forgotten to do it before the last move.  

She went to bed and woke up the next morning in a brain fog and a little disoriented.  The two original packets mixed with the new one created a chemical reaction that could have killed her had she not left a few windows open.  I mostly use just water because we use our septic system every day.  If I feel the need, I add a few ounces of Rid-X.  This is specifically designed to break down waste in septic tanks.rv black water tank

RV Black Water Tank Problems

Happy Camper Rocks!

Use a tank rinser to keep your black tank from developing excessive residual solids.  As I mentioned, even in the best conditions, not everything inside the RV’s black water tank is flushed out. One thing you can do is fill the tank with fresh water and dump the tank again.  That can help to remove the leftover solids.  

Some RV manufacturers install tank flushers inside the black water tank.  Using that system after every dump can help to keep the tank clean.  Just don’t use your fresh water hose to attach to it!  I witnessed an RVer do this the other day – yuk!!  What happens if you get some backflow?

Use a flexible swivel stick to clean your RV’s black water tank completely. I had not used one until we got our newer RV.  Given it is a motorized RV and it sits lower to the ground, we don’t get the same evacuation flow that we got with the 5th wheel.  We also keep getting tank level readings 1/3 even after dumping the tank.  

So, I purchased a Camco flexible swivel stick to help push the remaining crap out of the tank.  This works great!  It sprays a high-pressure stream of water around the entire tank and removes the leftover solids.  

I know it works because when I shine a flashlight down the toilet into the black tank, I can see the difference between before and after I use it.  Before use, brown stuff; after use, I can see the bottom of the black tank!  And the tank gauges also report empty after use.

rv black water tank

Given that most RV black water tanks are not a straight shot from the toilet bowl into the tank, the Camco flexible swivel stick is the best choice to be sure to get the job done right!

rv black water tank

Regardless of the method you use based on the list above, considering all the ideas above will keep things flowing smoothly out of your RV black water tank. These steps will also help to prevent a situation that would not allow you to use one of the most needed items inside your RV!

Please feel free to share your crappy stories.  This is truly one of the joys of RVing, and we must have a laugh or two about the things that do happen!

Happy Crappy Free Travels!!


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    • Charnell on March 13, 2020 at 2:05 AM
    • Reply

    We have an older fifth wheel. The inside reeks. We saw some leaking underneath and think it’s the black tank. If we empty often then it quit leaking. The bottom is winterized so we can’t tell if something crawled up there and died or if there is black water sewage sitting under there. We called for repairmen and some won’t work on black tanks. Others are too busy. The smell is atrocious and keeping me up at night. Any ideas? Could we be getting methane gas leaking out? We are living in Florida for five more weeks.

    1. Hi Charnell!

      If you are emptying the tank often and there is no leaking, then there may be a crack in the tank at a mid-level range. If the trailer has a sealed bottom, it sounds like it is time to rip out the membrane where the blank tank is located. The smell may be coming from the insulation that has absorbed the black tank waste. You need to get a look at the tank to really know what to do moving forward. You can’t rely on others for this. No one wants to work on black tank issues! Once you are able to look at the tank you can run freshwater into it to find where any leaks might be and make repairs. Good Luck!!

    • Christina on March 25, 2019 at 9:12 PM
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    Anyone ever have the end of their swivel stick come off in the tank if so what did you do to get it out

    1. Hi Christina!

      I have not heard of this one but I now know that this can happen.

      The end of the cleaning wand is not that large so it should flush out with a full tank of liquid. I am not sure you want to go looking for it, LOL. Also, I would fill the tank up several times to be sure everything flushes out. If you have a clear adapter on the gate valve area you may be able to see the part come through so that you will know it has made its way out.

      Good luck!!

    • Cathy on September 18, 2018 at 3:04 PM
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    Good Morning, We have a 28 ‘ RV we live in permanently. Our problem is we are getting sewer smell from the black water tank when it is almost full. Before we noticed this we could see the tank was getting full by seeing the wastewater. We usually drained it before seeing the water usually..Well, now we never have seen that it was getting full and we started smelling the sewer gas. So the next day my husband dumped the tank and the next day the smell seemed to be gone. Well, it is about time to dump and the smell is back. So where do we start? We have enclosed bottom of the RV also so don’t see anything unless we take off sheeting. Thank You for any help you may have.

    Cathy & Norm Peterson

    1. Hi Cathy!

      Thanks for stopping by our website!

      Let me ask you two questions: does the toilet bowl hold water if you place some in it and does it stay in the bowl for more than just 30 minutes? Also, have you isolated where the odor seems to be coming from?

    • Sara on August 5, 2018 at 7:59 PM
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    After dumping and cleaning our black tank, my husband wants to put a few gallons of clean water in our clean black tank and add a Camco TST Ultra-Concentrated Orange RV Toilet Treatment Drop-Ins in between our camping trips.

    Is it safe to leave a clean black tank with a couple gallons of clean water and a drop in treatment for a couple weeks between trips?

    1. Hi Sara!

      Thanks for stopping by and commenting!

      There are many that believe that this method is a good way to go. Being that this is a website about full time RV living, we have never had to deal with this issue.

      However, using common sense, putting anything in the black tank is okay, as long as it is designed for the purpose it is intended and over long periods of time, it will not affect the tank or blade seal of the dump valve. Check the caution label of the product you are using to see if it states there are side effects of their product remaining in the tank for extended periods of time.

    • Bloggin Brandi on July 25, 2018 at 7:48 AM
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    Whoa now this is pretty cool! I can’t wait to check this out on Amazon! I have had this issue now being able to clean deep in the tank. I was trying to use a straight rod to clean and no help obviously. Super cool!

    1. Thanks for stopping by and sharing Brandi!

      Happy RVing!

    • Scarlett on June 29, 2018 at 5:30 PM
    • Reply

    Hi Howard,

    I have a Dolphin Motorhome that has been setting for 7 years not being used. It was left with some waste still in the black tank. What would you suggest for cleaning this out?

    1. Hi Scarlett!

      At this point can you open the gate valve, put water in the tank and see it running through the sewer hose or is the gate valve totally blocked and unable to be opened?

    • Bill on June 21, 2018 at 8:40 PM
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    We have 95 minnie winnie rv and our black water tank or the pipes from it leak a little. Emptying it there us stuff in the pipe already & we haven’ t opened the valve yet. What could it be?

    1. Hi Bill!

      Thanks for stopping by our website!

      My guess is that your gate valve seals are leaking a little allowing fluid to get by and collect at the sewer cap. They do that as they get older. Unfortunately, there is no easy fix for that. The valve needs to be opened up and new gaskets put in.

    • Roger on June 15, 2018 at 9:41 PM
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    I have a problem with my black tank. Dropped a small air fresher can in the toilet. How can I get this out. I don’t want to drain the tank because it will get stuck in the 90 degree elbows.
    Help please

    1. Hi Roger!

      Thanks for stopping by our website! Not anything I have had experience with or heard of.

      I don’t know how you could fish that out from the toilet other than a really strong magnet and going fishing. The chances of grabbing it are small but you never know.

      The only other may is to pull the valve, let it get stuck and hopefully, most of the liquid would drain so that you could cut the elbow out and remove the can that way. It would be messy but either way you are in for a project.

      Best wishes!

    • Jena Chatman on June 2, 2018 at 8:35 PM
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    I have an older holiday rambler aluma lite 5th wheel that only has one tank. And it smells like sewage every time we flush. I don’t know a thing about it, any help??

    1. It could be that the tank is not venting properly. Check the roof vent to see if it is clogged. Also be sure you are not running the bathroom vent while you are flushing the toilet. It can draw odors up from the tank.

    • Dee on April 30, 2018 at 11:06 AM
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    We are de-winterizing our black tank for the first time and there is fungi coming out of the black tank. Is that normal? Is it possible to avoid it? What’s the best way to be sure it is completely out?

    1. Hi Dee!

      Thanks for visiting our website!

      It is possible to see debris coming out of the black tank, even if it has been flushed with clear water. Over time the sidewalls collect a thin layer of buildup and it can flack off and that may be what you are seeing. Even if it is a fungus, I would not worry about it. It is in a sealed tank with no way for it to make its way inside. Be sure to use a good tank additive this camping season and I am sure the issue will correct itself.

      If it is still a concern for you, there are services that use a high-pressure sprayer to clean out the black tank.

    • Henry Stumpf on October 8, 2017 at 5:29 PM
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    I recently checked holding tank levels. The black tank indicated full so I dumped. The 30Loftk sits on a site full time. After I emptied the indicator still showed full. I went back out and opened the black handle and nothing came out. Tank is empty but gauge still indicates full.

    1. Hi, Henry!

      Black and Gray tank sensors will work for a while but eventually give inaccurate readings depending on the sensor type and the tank design.

      The black tank can be maintained if you keep the tank clean with an internal tank flush, the RV black tank cleaning wand, or even filling and emptying the tank with fresh water a few times.

      As I stated in the article, we use the cleaning wand which keeps our black tank reading properly. The gray tank does not as we have no access to it for the cleaning wand. Most commercial tank cleaners have had little affect for us with the tank design we have.

      Try these few methods Henry and see if that helps!

    • James Jacks on July 17, 2017 at 5:48 PM
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    I have a Glendale tiatium 5th wheel. I use proper tp and lots of water But I will dump one day and clean wit a wand and the next day after a few flushes the top portion will fill up. Gauges show nothing in the tank but it starts to back up. I get the wand and flush and clears Any solutions to his to solve this problem need help

    1. Hi, James!

      Thanks for stopping by our website!

      Is the pipe from the toilet down to the black tank a straight shot or does it take a turn before reaching the tank? DO you have an endoscope that you can use to investigate down into the clogged pipe? You can buy them at Amazon for as little as $30. Link: https://www.amazon.com/gp/product/B00STB0EW6/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&tag=wwwyourfullti-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B00STB0EW6&linkId=26fbfe2647b8541cbb9e5037078d9115

    • Glenn McFeeters on June 9, 2017 at 4:13 PM
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    Even an old hand can still learn a thing or two. 7 1/2 years with this RV and years before, I never dealt with the “black mound of death” till now! I have always left the valve open after setting up and rairly worried that we didn’t use a lot of water. We have been on the road for about a month and it caught up to me, opps. I put lots of water along with 10lbs of ice in the tank and am hoping that when we dump that the ice will have scoured the tank and put me on the path to a cleaner way of doing my “business”. Gotta get me a swizzel stick!. Thanks for the idea.

    1. Hi, Glenn!

      I am glad you found our website useful in your search for a solution to the “black mound of death.” LOL

      I have seen Youtube videos about the usefulness of ice in the black tank to break up the toilet paper mound. If that does not work you can hire professional services that have the equipment to clean out your tanks.

      Happy travels!!

    • Mary C Allen on June 4, 2017 at 9:40 PM
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    Howard, thank you for the information! We are not using enough water! Only used our campers five times now. After not even one day, meter read black was full? We went to dump after day two and when we opened the cap, black water came rushing out! Gross! We hurried to put on hose. Do you know why this would happen? Camper sat for six months in Arizona for the winter. We are in Idaho now when this happened. Could it be a bad valve? Help! Tank shows still 1/3 full after dump.

    1. Hi, Mary!

      Was the gate valve open when you took the sewer cap off? If not then the gate valve may be stuck in the open position. Tank monitors typically give false readings unless the tanks are properly maintained by using the tank flush feature or a swizzle stick.

    • Clark Ortiz on May 8, 2017 at 9:36 PM
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    So, here’s my story. Brand new rv’er, new rv, first time blackwater dump. Class c, 3 weeks after I bought it. 2 campgrounds, lots of water, 8 “#2.” 1 roll rv toilet paper. Hook up to dump station, open valve, only redistribution factory winterizing solution. About a cup. Nothing.Close valve retry. Nothing, close and open greywater, woosh! Close it. Tons out, at the factory, when they cut out the hole for sewer connection, they dropped the cutout plate into the tank! Yeah, super hosed!

    1. Hi, Clark!

      Thanks for visiting our website!

      Sorry to hear of your issues! The good thing is that you are under the factory warranty and you can take it back to the dealership for repairs. I know that’s not convenient, but at least you have that option.

      Good luck!!

    • Jon on April 20, 2017 at 12:59 PM
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    Thanks for the great info on black tank problems, I am having a problem now with the black tank electric valve not closing all the way, I replaced the two years ago for the same problem, It has to be a paper jam I think, The valves are very hard to get to as they are up under the fifth wheel under the bottom protective sheet, buried in insulation. another problem was the exit to hook the flex dump hose had only a cap, I installed a hand operated slide valve to stop any surprises, I think I will keep trying to get the valve free, I can hear it trying to close, If I have no luck I will get under the fifth wheel and rip out the 3 inch electric valve and replace it with a cable valve, then always take your advice and do a better job of emptying the tank. I need to be more responsible in that, I will be 80 years old next year and crawling under that monster is getting to be a pain.

    1. Hi, Jon!

      I am not a fan of the electric valves: too much to go wrong. The manual type can be enough of a problem to keep operating properly if not maintained.

      Good luck on your project and thanks for stopping by!

    • henny on August 11, 2016 at 7:02 AM
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    Wow I really enjoyed reading your Posts.Great information.

    1. Thank you! We are glad you stopped by! I just flushed mine out again today! It’s a weekly thing when you are enjoying the full time RV lifestyle!

      • robert on February 21, 2019 at 5:13 PM
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      ? so are you saying if you are at a rv park with sewer hook ups leave the black tank valve closed until it is either full or you are leaving ? thanks for any help new rvers

      1. Hi Robert!

        In answer to your question, yes! Always leave your black tank closed otherwise all the liquids will run out leaving all the solids. Eventually, you will not be able to remove what is in there. If the gate valve is left closed and not opened until the tank is at least half full the long term results will be better. That way the liquids and solids have a better chance of leaving the tank.

        We do not empty out the black tank until the tank is full. If we need to empty it before it is full because we are traveling and don’t want to carry the weight, I fill the tank with water and then empty the full tank (we have a tank flush system that makes this easier). Even then I have to refill the tank with water and dump it again to get most of the “crap” out. And once a month I use the cleaning wand to help keep the sensors clean.

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