How to Get Dried Poop Out of the RV Tank?

RVs are an incredible way to get the most out of your vacations. Laden with almost all the vital amenities, they are essentially a small apartment on wheels. However, cramming all the systems into a tight space has its downsides as well. One major downside is the potential problems related to the dreaded black tank. The black tank is one of the two storage tanks for wastewater, the other being the gray tank. The gray tank stores all the wastewater from the sink and the shower, whereas the black tank only holds the waste from the toilet.

Understandably, the black tank is made as such to have a storage capacity of several gallons. Therefore, RVers can go about their business without having to drain it frequently. Though, there are times when the black tank doesn’t function as expected of it. There can be numerous underlying reasons causing the headache, but it is often a poop pyramid that has caused a blockage in the system. Worrisome as it sounds, the good news is there are several solutions you can deploy to tear through this pyramid.

However, before we venture on to enlist and describe the remedies, it is important to detail another most common potential cause that may be clogging your RV toilet:

Clogged Pipe

Generally, the pipe underneath an RV toilet leads straight to the black tank. In certain RVs, the drain pipe takes several turns before it reaches the tank. These turns can lead to the accumulation of solid waste, especially if you are a bit conservative when it comes to flushing your toilet. The incessant use of toilet paper can also cause blockage around such bents. Many people confuse a clogged toilet pipe with poop build-up in their black tank. Nevertheless, the remedies for both are rather similar as will be evident in the following passages.

Poop Pyramid

The poop pyramid, as the name suggests, is a somewhat giant pile of solid human waste that has stuck in the way of the tank drain. Disgusting as it sounds, you will have to deal with it to use one of the most vital components in your RV i.e., the toilet. The main culprit again is not using enough water after doing #2. While not using enough water may be the prime reason, the other leading cause or should I say the mistake that leads to the accumulation of solid waste in the black tank is keeping its valve open all the time when connected to a dump.

Understanding the Poop Pyramid

Keeping the valve of the black tank open at all times may seem like an innovative idea that would save the hassle of turning it on and off now and then, but this is just wishful thinking. The reality is that an open valve allows all the water to drain and doesn’t allow the solid waste to dilute with it. This ultimately leads to the gradual accumulation of solid matter and thus the poop pyramid.

This accumulation blocks the exit of waste and can lead to weird readings from the tank sensor, especially when you have drained the tank. The abnormal reading from the tank sensor should be a good telltale sign of waste accumulation in your black tank. Other symptoms pointing to a poop pyramid are slow or very little drainage from your camper’s toilet. Lastly, if there’s nothing or very little coming out of your sewer hose then there is a good likelihood that a poop pyramid is blocking the passage of waste material.

Addressing the Issue

Now that you have confirmed the presence of a poop pyramid in the black tank or a blockage in your waste drainage system, it is time to address the issue. The solutions are rather straightforward and the majority of the time there’s no need to call a professional.

Just REMEMBER to close the black tank valve before you do anything to break the giant poop pyramid. Here are our top picks as to what can get you rid of a toilet pipe blockage or a poop buildup in your RV black tank.

Using a Plunger or a PEX Pipe

As already mentioned, it is easy to confuse a clogged toilet pipe with a poop pyramid in a black tank. If you haven’t left the black tank’s valve open or if you are a regular user of your RV and have been using ample water to flush the toilet but still the water won’t go down the toilet or doesn’t come out of the sewer hose, then a clogged pipe can be a likely cause.

To unclog such an obstruction in the pipes, start with the basics. Try plunging, if not at initial attempts, then this method certainly works after several attempts, provided there’s a blockage in the pipe.

If it still doesn’t work, then it’s time to bring in a PEX pipe. The flexibility of the PEX pipe allows it to maneuver around the bends of the pipe attached to the toilet. If PEX pipe isn’t available, then a swivel stick would also do the job just fine. Push the pipe/swivel stick down the toilet and move it around several times.

Important to remember is the fact that the PEX pipe and swivel stick usually works for both clogged toilet pipe and a poop pyramid in the black tank. Therefore, the chances of success are good with both of them.

Blasting it Away

Usually, the poop pyramid has gotten hard over time, so it is often difficult to break it with normal water pressure. If there’s a straight pipe connecting the toilet and the black tank, then the poop build-up in the tank can be blasted away using high-pressure water. All you need to do is to connect a high-pressure nozzle to a garden hose and blast away the accumulated waste in the tank that you can see through the toilet. If there are bends in the pipe, then a special hose would be required. You can get any kind of special hose for this purpose, though many prefer the one made by Camco.

The Enzyme Treatment

As you may already know, a poop pyramid is a giant buildup of organic waste and such waste can be successfully torn down using enzymes such as baker’s yeast. You can also use RidX, though it will be a pricier alternative. Regardless of which route you go, pour an ample amount of a good enzyme drain cleaner and let it sit in the toilet for a day or two. Then flush the tank twice and again let the enzymes do their job down below for a day or two. The enzymes will work to gradually break down the accumulated poop. You can use this process in conjunction with a PEX pipe or a swivel stick which may help in accelerating the process. After two days, dump the tank and see if there’s been any progress.

Happy Campers Extreme

Happy Campers is a renowned product that is used by many to unclog their drains. Therefore, it can be successfully deployed to get rid of the dried poop from the RV tank. Aside from being a great sanitary treatment product, it also boasts the capability of being organic which is an added extra for people who are conscious about the environment. Its extreme version is particularly suited for getting rid of hardened poop in the black tank. Just follow the instructions on the box and with some luck, you will get rid of not only the poop pyramid but also any foul odors that may be coming from your RV toilet or tank.

Dishwasher Liquid and Water

While this is a relatively controversial way of getting rid of dried poop in the black RV tank, nevertheless, it is worth a try especially if you haven’t got enzymes, RidX, or even a swivel stick. Add dishwasher or dawn soap into your toilet and flush it. Repeat the procedure and allow the drained mixture to sit in the tank for a day or two. The good thing about using a dishwasher or a dawn soap solution is it stimulates healthy bacteria instead of getting rid of them. This stimulation helps in the breakdown of dried poop buildup and eventually, you will be able to get rid of the waste pile.

Dawn Detergents x Calgon

Dawn liquid detergent is known to be an excellent grease cutter so it can be an effective way of tearing apart the pyramid of dried poop. To supplement the detergent, add half a cup of Calgon liquid. Once done with the first flush, repeat the process but this time add slightly less quantity of Calgon. Allow this solution to sit for a few days in the tank and then drain. Hopefully, the dried poop build-up would be torn apart by then and you will be able to use your RV to the fullest.


Dealing with a dried poop build-up in your RV’s black water tank can be an incredible hassle, particularly if you have taken every precaution to avoid it. It can be very agonizing if you are just on the verge of taking your RV on a planned adventure. However, you can only deal with this dilemma with a clear head. Begin with turning off the black water tank valve and diagnosing whether or not the blockage is in the toilet, pipe, or tank. Afterward, start with the most basic remedies that have been described above. If one doesn’t work, then move on to the next one. There are good chances you will be able to break that dried poop with the tried and tested methods we have detailed for you above.


There are a few different things that can cause dried poop in your RV tank. One thing that can cause this is if you do not empty the tank regularly. Another thing that can cause this is if you let the tank get too full. Either of these things can cause the feces to dry out and become hard to remove.

You should never use bleach to clean your RV tank. Bleach is a strong chemical that can damage the tank and potentially harm you. Instead, use hot water and soap or a commercial RV tank cleaner.

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Ever since I was a kid, I've been fascinated by travel. I inherited this passion from my parents. Since my college years and to this day, I have had a passion for traveling in a motorhome. I am here to share my experiences with you.

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