Skip to Content

RV Nightmare: How to Unclog an RV Toilet or Tank

RV Nightmare: How to Unclog an RV Toilet or Tank

A clogged RV toilet might be one of the worst things that can happen to you on the road. This little-talked-about problem is actually quite common. But if not taken care of, an RV toilet clog could cause some major headaches—the worst being water damage from overfilling.

Having a toilet on the go is an amazing feature of RVs, but they can be susceptible to problems. If you’re experiencing a clog or just want to know what to do if it happens, read on to learn how to unclog an RV toilet.

Why Is My RV Toilet Clogged?

There could be several reasons why your RV toilet is clogged. The first and most common reason is waste buildup. Over time, waste can accumulate in the toilet pipes and cause a blockage. This can happen if you don’t use enough water when flushing or if you use too much toilet paper. You could also cause a backup if you flush non-degradable items like wipes or sanitary products down the toilet.

Additionally, if your RV toilet is old or damaged, it may not work as efficiently as it should, and this can cause clogs and other problems like leaks.

toilet paper in toilet
Using too much toilet paper can cause an RV toilet to clog.

Why Is My Black Tank Full But Won’t Drain?

If you’ve connected your RV sewer hose to the black tank drain and opened the valve, but nothing is coming out, you likely have a clogged valve or sewer hose. Similar to a toilet clog, this can happen when waste dries and builds up, creating a blockage. 

Another possibility is a malfunctioning tank sensor. The sensors that monitor the level of waste in the black tank can become faulty and incorrectly indicate that the tank is full, even if it’s not.

Lastly, a blocked vent pipe can cause a vacuum to form in the tank, preventing waste from draining properly.

How to Unclog Your RV Toilet or Tank

If you find your RV toilet is not flushing or you can’t dump your black tank, then you likely have a blockage. At this point, you need to try and break it up. Let’s take a look at a few methods to do this, from the easiest to the most invasive.

The Boiling Water Method to Unclog RV Toilet

First, try boiling water and pouring it down the toilet. The hot water will help loosen blockages and clear waste buildup to unclog the RV toilet. However, you may have to do this multiple times to clear the clog, so don’t give up if the first try didn’t work.

This usually only works when the toilet pipe itself is clogged. If your tank won’t empty, move on to another option.

Pressurized Water

If your toilet is not flushing at all, using pressurized water might not work. However, if it’s flushing slowly, you might have a chance. Hook up a hose and run it through a window inside the RV to the toilet. Use a sprayer nozzle to spray a high flow of water down the toilet and into the tank. The pressurized water will help dislodge any built-up waste. Make sure the tank drain valve is open at this point.

We personally use this technique to clean our black tank every so often while dumping.

If your tank is not draining, you can get a simple RV sewer tank rinser attachment that connects a hose to the tank’s drain valve. Turn the hose on and open the tank. This attachment will shoot water up through the valve, helping eliminate any clogs in the sewer pipes and black tank. You may need to turn the water on and off a few times.

Valterra 45 Degree Hydroflush Attachment with...
  • SEWER TANK RINSER: Breaks up plugged tanks and cleans tank, pipe,...
  • FUNCTIONAL: Internal backflow preventer and removable anti-siphon...
  • CLEAR CONSTRUCTION: Clear walls allow you to see when water is...

Using a Plunger or Toilet Snake

The next option is to use a plunger to help dislodge any blockages in the pipes between the toilet and the black tank. However, a plunger might not be the most effective if there isn’t an airtight seal.

If plunging doesn’t work, use a toilet snake. Make sure you get a snake long enough and sturdy enough to really grind up anything in the pipes. 

Insert the snake into the toilet and through the adjoining pipe, then push back and forth and spin it. The snake will loosen and break up debris and allow it to flow. You can also snake the black tank drain pipes if your black tank won’t empty. However, if you are trying to dump the tank, you could end up spilling sewage when the clog breaks up, so have a bucket under the drain to catch any spillage.

Unclogging an RV toilet with a plunger or toilet snake is best done by someone who isn’t completely grossed out by the toilet, as it might be a messy process.

plunging an RV toilet
A plunger can help dislodge any blockages in the pipes between the toilet and the black tank

Unclogging Your RV Toilet or Tank With Holding Tank Cleaner

You could also try holding tank cleaner. Because black tank cleaner breaks down human waste, it could help break down the clog. The issue with this option is it won’t eliminate the clog, and it could take a few hours to take effect.

To use it, add the cleaner to the tank along with a few gallons of water if it will go down, and then take the RV for a drive. Make plenty of turns to slosh the cleaner around and help it break everything up. Then try flushing out the tanks and running the toilet.

Pro Tip: Make sure you use RV-safe cleaning chemicals to unclog your toilet. Before you begin, find out What RV Toilet Chemicals Should You Use?

Tips for Preventing RV Toilet and Black Tank Clogs in the Future

The best way to avoid a clogged RV toilet is to take preventative measures. There are a few things you can do to help limit clogs in the future. 

Keep Black Tank Valve Closed Until Ready to Dump

The best prevention is not leaving your black tank valve open except when dumping. If you leave the valve open when using the toilet, it allows solids to build up in the tank. When you attempt to dump, this mass can clog up the tank output.

Leaving your tank valve open can also create a “poop mountain” directly below where the toilet drains into the tank. This is because the liquids will drain out immediately, leaving the heavier solids behind. Eventually, this mountain will grow and completely block your toilet from draining into the tank.

The easiest solution is to let the tank fill until it’s time to dump. You can dump the tank at any point, but the more liquid in the tank, the better.

dumping RV black tank
Keep your black tank valve closed until you’re ready to dump.

Only Use RV Toilet Paper – Or Put Paper in the Trash Instead

Never flush anything other than RV toilet paper down your toilet. Flushing regular residential toilet paper or feminine products is sure to cause issues. The best thing you can do is throw toilet paper in the trash. But if that’s not something you can stomach, only use RV toilet paper. It’s made to dissolve quickly, so you’ll have to unclog your RV toilet less often.

RV Toilet Paper, Septic Tank Safe-MADE IN THE USA-...
  • BEST RV TOILET PAPER - 8 super soft rolls per pack, 500...
  • FAST DISSOLVE TOILET PAPER - Our quick dissolve toilet paper is...
  • RV SEWER TANK SAFE - Our septic tank safe rv marine toilet paper...

Use Plenty of Water With Each Flush

Too often, people don’t use enough water when flushing. However, using plenty of water will ensure that anything going down the pipe doesn’t get stuck there and passes to the black tank. Make sure you push down on the flushing lever or pedal long enough to allow plenty of water to pass through the pipes and into the black tank.

You could also eliminate RV toilet clogs altogether by investing in a waterless toilet. Composting toilets and incinerator toilets are two good options!

Use RV Waste Tank Treatments

Another preventative measure is to use black tank treatments regularly. These chemicals break down human waste, which helps prevent clogs and build-ups. We recommend using Happy Campers Holding Tank Treatment

Happy Campers RV Holding Tank Treatment - 64...
  • ODOR FREE: Eliminates odors in the RV holding tank. Absolutely no...
  • Septic tank friendly
  • EFFECTIVE: In extreme hot & cold temperatures ( over 100 Deg)

Did You Know? Holding tank treatments also help fight off the dreaded RV toilet odors. Learn more here: 5 Reasons Why Your RV Toilet Stinks

Clean Your Black Tank Each Time You Dump

Lastly, clean your black tank every time you dump. Many RVs come with a built-in black tank flush inlet that allows you to connect a hose directly and rinse out your black water tank without having to run water through your toilet. 

If your RV does not have a black tank flush or it does not work, you can run a hose into the RV and flush the tank through the toilet. Or, as mentioned above, you could buy an RV tank rinser attachment that shoots high-pressure water up into your blank tank to give it a good rinse.

How To Dump & Clean an RV Black Tank

Never Store an RV With a Dry Black Tank

Unless you’re sure that your RV black tank is super clean, never store it empty. Any solids left in the tank will dry up and can contribute to a clog in the future.

The best way to store an RV’s black tank is partially full of water with black tank chemicals. This will make sure any solids dissolve in the time stored. If storing in freezing temperatures, also be sure the tank has antifreeze in the water and that the tank is not more than half full. Doing this will make sure your black tank is ready to go come camping season!

If Your RV Toilet Clogs, You’ll Be Ready!

We hope that our tips today help you prevent it, but now you know how to unclog your RV toilet in the worst-case scenario. If it does happen, don’t be ashamed. This is a common problem almost everyone encounters at some point. It’s not a big deal, but you want to make sure to take care of it before it becomes an issue.

RV bathroom with toilet

Become A Mortons On The Move Insider

Join 10,000+ other adventurers to receive educating, entertaining, and inspiring articles about RV Travel Destinations, RV Gear, and Off-Grid Living to jump-start your adventures today!

About Mortons on the Move

Tom & Caitlin Morton of Mortons on the Move gave up the stationary life for one where they are constantly on the move. They are full-time travelers, television hosts, and digital media producers.
They left their jobs, sold their house and possessions, and hit the road in September 2015 in their full-time “home on wheels”. Since then they have traveled the US, Canada, and even internationally by RV.
Now, they are Discovery Channel & PBS TV Co-stars of The RVers, producers of “Go North” on Amazon Prime, co-founders and instructors of RV Masterclass, and contributing authors for and an Arizona travel guide.

About Us

Sharing is caring!


Thursday 9th of March 2023

Here is a video on how to easily open a clog

Mortons on the Move

Thursday 16th of March 2023

That's a neat technique! Thanks for sharing the video!


Sunday 30th of January 2022

Hi! I’m curious about your toilet? Is it a household toilet? There would be nothing to plunge in mine because it is a straight shot to the black tank. Thanks! We were just discussing if you should ever use a plunger on an RV toilet and came across your article.

Mortons on the Move

Tuesday 8th of March 2022

So in some RV's its not a straight shot, but most are. It is possible if somone leaves the black tank open to get a pile buildup that blocks the pipe. We have macerator toilets that can get clogged as well.

Cyrus Juliet

Tuesday 7th of September 2021

To unclog an RV toilet, simply use boiling water. However, ensure that the pieces of your toilet are strong enough to withstand the high temperatures.

Roof Leaks

Monday 22nd of February 2021

A clogged RV toilet can lead to a nasty smell that can permeate the interior of the vehicle and make your trip unbearable. If you find yourself in such a predicament, then there are different ways as you have already mentioned which can unclog your RV’s toilet holding tank.


Sunday 7th of February 2021

The most important piece of advice is using lots of water. But you forgot one thing. When storing your RV make sure you have water And treatment in the black tank. Don’t store with the black tank dry, unless you are absolutely sure it is clean.


Monday 8th of February 2021

I literally just read an entire paragraph or two about halfway into the article or whatever u wanna call it that went over this extensively lol. They didn't forget.

Mortons on the Move

Sunday 7th of February 2021

Great point!