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RV Black Tank Flush: How To Clean An RV Toilet Tank

(Camp Addict does NOT accept payment from any company to review or endorse their products.)

Kelly Headshot

By Kelly Beasley

Published: September 20, 2021

Last Updated: November 12, 2021

RVing is a lot of fun! With it comes freedom, exploration, adventure, and poop maintenance.

Oh, poop maintenance wasn't on your list of amazing RVing things? Shocker.

Well, I didn't ACTUALLY think so. Nevertheless, it IS a 'byproduct' of RVing life.

If you RV, you must maintain and empty your holding tanks for campers. This includes your gray water tank(s) and black holding tank.

Family sitting in chairs in front of Class C motorhome

Yep, this part is zero percent glamorous!

But unless you hire some handyman to do such a ridiculously easy job, you're going to have to tackle your RV tank maintenance yourself. Might as well learn how!

RV Black Tanks 101

Your RV has at least one holding tank. But the norm is two holding tanks: the RV grey water tank and the RV black water tank.

The gray water tank holds all waste water except for toilet waste. The black tank holds all the toilet waste.

These waste water tanks keep filling until you dump them using the dump valves and a sewer hose.

Black tank issues arise if you don't maintain the system properly.

Problems include:

  • Getting a clog
  • Developing a poop pyramid
  • Sensors reading wrong
  • Odors

Let's look at black tank management and maintenance a little more in-depth.

RV Black Tank Management

Holding tank

Ok, you're going camping this week. You'll be at a campground with full hook-ups.

This means you can connect your sewer hose to the sewer, have a water supply, and power.

Rule number one is NOT to open your black tank valve unless you are actively dumping. Keep that sh** closed at all other times to avoid the dreaded 'poop pyramid'.

If you have odors or want to break solids down, use a tank treatment that deodorizes and uses enzymes to break down the contents.

When you flush, use plenty of water. (OR, don't put TP down the toilet. This almost guarantees you will never have an RV tank clog!)

Lastly, allow your black tank to become close to full (or full) before you dump it into the sewer connection.

Why?

The theory is that the more volume of liquid, the faster and more forcefully the contents will escape. This eliminates any type of buildup that can occur otherwise.

As far as maintaining your RV tank and your tank sensors, it's best to do an RV tank flush periodically.

What Is A Black Tank Flush System?

Tornado tank flush

A black tank flush system is any device that is made to rinse out the inside of your RV black tank.

The RV black water tank holds all the 'loveliness' that goes down the RV toilet.

An RV black water flush system usually involves an inlet for you to connect your rinsing hose. You may need to buy an RV holding tank cleaner device if yours doesn't have one built-in.

Why Does The RV Black Tank Need To Be Flushed?

Your black tank does not necessarily NEED to be flushed.

Popular thinking claims that flushing will clean out anything stuck to the walls of your black tank. Some styles of the flushing tank rinsers will help. Other RV holding tank rinsers will not.

That said, I have never done an RV blackwater tank flush on my travel trailer. Even so, I've never had an issue in my six years.

That said, recreational vehicle owners who flush regularly very well may prevent toilet paper from causing the RV holding tank level sensors to misread.

It might also help prevent struvites from forming on the sensors and tank walls, also causing sensors to misread.

Bear in mind that it's hard to find RV owners that bother to try to keep their sensors working properly. It is a hopeless battle for motorhomes and trailers equipped with the most common probe style holding tank sensor.

You'll learn how long you can go and your toilet will also make a noise indicating it's time to dump. I have lived in my RV full-time for about six years without working black tank sensors with no issues.

Trixie dog lying down in front of Kelly's RV outside of Glacier

How Do You Flush An RV Black Tank?

Flushing an RV black tank sewer system is a straightforward process. It involves only a few steps.

  1. Connect your sewer hose, open your black tank valve, and dump your black tank into a dump station.
  2. Connect the water hose to the flush inlet or to the flush device.
  3. Turn on the water and let the RV flushing mechanism do its thing for a minute or two.
  4. Be careful not to overfill the black tank. It will back up into your RV if you do! This is why it is advised to keep your black tank valve open while flushing.
  5. Keep it going until the the drain water runs clear (though a video we show down below proves that water running clear doesn't necessarily mean your tank is truly empty/clean).
  6. Shut off the water supply and allow all water to drain.
  7. Remove the sewer hose, close your black tank valve, and you're done with the dumping process and RV holding tank cleaning.

How Long Should You Flush A Black Tank?

You should flush a black tank long enough to see clear water draining out of the RV's sewer outlet.

If you don't have a clear connector somewhere on your sewer hose or in-between it and the RV, buy an attachment. This allows you to observe the flow of water while you perform an RV sewer flush.

Generally, this RV black water flush should take no more than 1-3 minutes to complete the job.

Can You Add A Black Tank Flush System?

You sure can add a black tank flush system if your RV doesn't have one built-in.

There are a couple of different types of RV black tank flush kits to choose from.

There is a handheld RV tank wand available from Camco. This RV toilet wand is made to be stuck down into the toilet.

Connected to a water hose, it sprays water all around the tank.

Camco swivel stick

Camco Swivel Stik

Second, you can get a black water tank cleaner attachment to your sewer outlet. This attachment has a hose connector that you connect your water hose to.

It shoots water up into the tank, supposedly cleaning it all out. (Spoiler Alert: this style doesn't actually do anything. There is no RV black water tank cleaning going on with this attachment. See video below.)

Third, you can install an RV tank cleaner that works inside the tank. The Camco Tornado is the product we are referring to.

Tornado tank flush

Tornado Tank Rinser

Can You Put Bleach Into The RV Black Water Tank?

Sure, you can put bleach into your black water tank, but it's not advised. Bleach won't do much to help your black tank.

What it MIGHT do is wear down the seals that keep liquids from leaking out. You don't want that, do you? (Hint: You don't!)

How Do You Deep Clean An RV Black Tank?

The best way to deep clean an RV black tank (or grey tank) is to have the inside pressure washed.

You can hire someone to do this (a mobile business), or you can buy an accessory that spins around inside the black tank, acting as a gentle power wash.

Real power washing will be much more effective in removing struvites. A struvite is a sediment present in all sewer systems.

This eventually builds up on the sides of your tank, potentially causing your tank level sensors to read wrong at the monitor.

What Are The Best Mechanical Black Tank Cleaners?

There are only a few good mechanically effective black tank cleaners on the market. Here are a few popular ones:

Tornado Rotary Tank Rinser: This installs INSIDE your black tank. Once installed, you connect a water supply and let 'er rip! It slings water all around, likely removing any debris or dookie bits off of the walls. It helps finish draining stuff from the bottom as well. Watch this video by The Fit RV for proof (below). We could not do a better review than theirs. Watch for yourself to see what we mean. Jump to about 18:25 for the Tornado rinser test.

Tornado tank flush

Tornado Tank Rinser

Camco Swivel Stik: This gem of an RV black tank flush kit allows you to reach everywhere inside the black tank. We believe this is the most effective way to get all debris off of the walls of your black tank. You can lower and raise this RV black water tank cleaning wand to get the most coverage. This is something NONE of the other products accomplish. Plain logic says that a black tank cleaning wand is the most effective product of them all as it gives you the most control.

Please note that in order to use an RV black tank flush wand, your toilet must be mounted directly above the black tank so that the wand has a straight shot to access the tank. If your waste tank is mounted away from the toilet, there will be plumbing pipes between you and the tank, which the Camco black tank wand won't be long enough to reach past.

Camco swivel stick

Camco Swivel Stick

Camco Rhino Blaster: Welp, in the video above, it is pretty much proven that this style of RV holding tank rinser doesn't work at all. This RV black tank cleaning product (and any similar ones) is a waste of money. Don't bother buying one. This proof is also in the above video. Still, if you MUST buy this type of RV tank rinser, here's a link for you below.

Camco Rhino Blaster Pro

Rhino Blaster

How Often Should You Flush Your Black Tank?

There is no right or wrong answer when it comes to how often you should flush your black water tank.

Some people flush their black tank every time they hit a dump station. This is how Camp Addict co-founder Marshall does it, using his built-in RV black water tank flush system on his travel trailer.

Others do the black water tank cleaning every few dumps. Some people (like me) never perform a black water tank flush on their RV. It depends on your comfort zone.

What a black tank flush does is simply dislodge any toilet paper or other debris that might be stuck to the wall or to one of your tank sensors.

Can You Use Septic Tank Cleaner In An RV?

You don't need to use a septic tank cleaner in your RV black tank. There is no such thing as a 'septic tank cleaner'.

They can be emptied and treated to increase microorganisms that break down the solids. To keep your black tank healthy and 'clean', you can do four things:

  1. Don't put TP down into the RV toilet tank. Put it into a trash can instead (#1 way to avoid clogs!).
  2. Use an RV black water tank treatment to break down solids.
  3. Make sure black tank is almost full before you dump so the volume of liquid forces everything out.
  4. Rinse it out by flushing the toilet while dumping, or use a black water flush kit (like one of the ones mentioned above) to do a more powerful cleaning.

How Do I Keep My RV Black Tank Clean?

Your RV black tank is never 'clean.' It literally holds waste- fecal matter and urine.

There's no cleaning it to get it sterile or spotless. You WANT bacteria and microorganisms in there.

However, you can use different methods to keep debris out of it and avoid clogs.

How Do You Get Rid Of A Poop Pyramid In A Black Tank?

To get rid of a poop pyramid, hire a professional to clean out the mess you made. (Haha!)

Alternately, if you want to do it yourself, you need to get water into your black tank.

A poop pyramid is EXACTLY what it sounds like. It's a pyramid-shaped pile of sh**.

Kelly grimacing

It happens when you leave the black tank valve open when camping with your sewer hose connected to a sewer, allowing liquids to drain out while the poo (and other solids) stays.

Or, worse, this happens if you store your RV without emptying the black tank first.

If the clog doesn't allow water to drain out of the toilet, start with a liquid plumber treatment to break through the clog.

If that doesn't work, get yourself some PEX pipe from the hardware store. You're going to use the pipe to physically bust through the pile.

The flexible PEX pipe gives you access to the tank even if your sewer pipe has a bend in it.

Once you have access for fluids to drain into the tank, fill the tank with water and a tank treatment that breaks down solids. Follow manufacturer's directions.

How Do You Use A Black Tank Wand?

Using a black tank wand is very easy! An RV black tank cleaning wand is made to stick down into the toilet hole with a water hose attached to it.

Connect the water hose, run it into the camper, down the toilet, and turn on the water. The RV tank cleaning wand acts like a sprinkler for your black tank.

Swivel stik in action

Let it slosh around at the bottom, then slowly move it up while letting the wand do its job.

Finally, once the water is running out into the dump station totally clear, you're done.

Turn the water off and remove the wand. Easy-peasy! We like the Camco Swivel Stik.

What Is The Best Black Tank Cleaner?

When it comes to choosing the best black tank cleaner, you have to understand what you are trying to accomplish.

If you are looking for a true RV black tank cleaning solution because there is an obstruction that needs to be removed, then you need a powerful RV septic tank cleaner such as Unique's Holding Tank Cleaner.

This camper septic tank cleaner is stronger than other tank treatments and is formulated to unclog waste tanks in 12 to 72 hours, no driving around necessary.

Unique tank cleaner

If you are looking for an RV holding tank maintenance solution and to keep odors down, there are a couple of great choices.

The top powder camper holding tank cleaner is Happy Camper black tank treatment. We have used this in the past very successfully to curb odors and to break down waste.

Happy Camper toilet treatment

If you want to stop struvites from forming, use TankTechRX, which is a liquid RV waste tank cleaner. But you must start with a clean tank (pressure washed to eliminate any mineral or struvite buildup) for this product to work properly keeping your sensors working.

In Case You're Interested, Here's Kelly's View/Belief That RV Tank Treatments Are Unnecessary

If you do just a few simple things and do them right, having a black water tank clogged will never be an issue.

Personally, in my six years of full-time RVing, I never performed a black tank flush. I also stopped using an RV black water tank treatment probably five years ago.

(Camp Addict co-founder Marshall does flush his black tank and does use a tank treatment, so to each their own!)

Waste Master hose coiled on grass

Also, the black tank sensors stopped working right from the start but I have zero need for them to work.

Why? I know about how long I can go before needing to dump.

I've also never subscribed to the 'use a lot of water when you go #2' theory. Even so, zero problems. (Because I don't flush my toilet paper!)

If I'm mistaken or don't keep track, my toilet will burp and let me know when I only have a few flushes left and should dump my black tank.

Do these things, and you won't need an RV black water tank treatment:

  1. DON'T flush your toilet paper. It can cause clogs and makes you have to dump sooner than later as it takes up a lot of space in the holding tank.
  2. Make sure your black tank is almost full before you dump. The volume of the liquids flowing out will remove most of the 'bits' from the tank.
  3. NEVER leave the black water tank dump valve open while connected to the sewer at a campsite. You will end up with the dreaded 'poop pyramid' clog if you leave your tank valve open.
  4. Use plenty of water when you flush your RV waste tank.
  5. If you choose to flush your TP, use ONLY septic-safe brands and go ahead and rip up what you break off before you use it. Try not to use a huge amount of toilet paper, either.
  6. ALWAYS fully dump your black RV tank before you store your camper. This method avoids a solid mass of poo at the bottom after all the liquids evaporate out.
  7. Odor problems: The one time you may want to use an RV black tank cleaner is if you are having odor problems. If you can smell it, it's probably hot outside. Heat causes the smell to get worse. There are RV black tank cleaning products on the market that help stop the smell.

Conclusion

Black tank flushers are tricky. Some work well. Others do not work well at cleaning RV black tank.

Flush methods vary, and we only recommend ones that are built into your RV or the Camco handheld wand.

Dump Station sign

Know you know more about how to clean out an RV black water tank. There are several different techniques when it comes to RV black tank maintenance.

All you need are a few items on hand for your waste tanks, a little knowledge how to use them, and a cleaning system for RVers to follow.

If you're that person who is in charge of the cleaning method for your tanks, stay on top of it, use some RV black tank flush system, and you should be good as gold!

Kelly Headshot

He-llllo. I'm the co-founder of Camp Addict, which my biz partner and I launched in 2017. I frigging love the RVing lifestyle but in December of 2020, I converted to part-time RV life. Heck, I lived in my travel trailer for over 5.5 years, STRICTLY boondocking for pretty much all of it. Boondocking is a GREAT way to live, but it's not easy. Anyway, I'm passionate about animals, can't stand campgrounds, I hardly ever cook, and I love a good dance party. Currently, I can be found plotting and scheming whether or not to start collecting farm animals (or plotting my next RV trip!) at my beautiful new 'ranch' named 'Hotel Kellyfornia', in Southern Arizona. 

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  • Great content here, thanks for sharing your knowledge. My wife and I are in process of finding and buying our first RV, so simple yet comprehensive tutorials like this are excellent to prepare us for realities we will face. Much appreciated Kelly!

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