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Having a bathroom wherever you happen to travel is one of the fantastic things about RV life. You can shower when you need to, use the restroom without searching for a public toilet, and freshen up whenever you see fit.

Of course, these conveniences do come with some drawbacks. The biggest drawback? Dealing with tanks—and more specifically, figuring out how to unclog an RV black tank. 

Related: RV Maintenance Essentials

Generally speaking, this isn’t an issue. You hook up your sewer hose, pull the valve, and out comes the contents of your black tank. Unfortunately, there may be times when the water just doesn’t flow properly during your dump session. In these cases, you have a clogged black tank. 

Below are our top tips for how to deal with a clogged RV black tank. 

Dumping the RV black tank

Image source: Mandruss

How Your RV Black Water Tank Works

First, let’s talk a bit about how your RV black water tank functions.

Essentially, your RV black tank is just a big tub or box that catches all of the waste that goes down your RV toilet after flushing. The tank then holds onto the waste until you hook up your sewer hose and pull the tank valve to dump. Once the valve is pulled, all of the wastewater flows out of the tank, through the sewer hose, and into the sewer. 

How to Unclog RV Black Tank

Of course, if the black water refuses to flow out of the tank when the dump valve is pulled, you have a problem. Fortunately, there are things you can do to unclog an RV black tank when it just won’t empty. 

Best RV Black Tank Treatment

If you don’t already use an RV black tank treatment, we recommend giving that a try before anything else when trying to unclog an RV black tank. Most RV black tank cleaner options actually work to break down solids, meaning pouring a good amount down the toilet and letting it sit for several hours might be enough to do the trick. 

The best RV black tank treatment? We prefer Happy Campers. Many also swear by using Dawn dish soap in RV black tanks, and a number of seasoned RVers use the “geo method” of cleaning their tanks, which involves using a combination of Dawn dish soap, Borax, and Calgon water softener.

No matter which method you choose to unclog an RV black tank, we recommend doing so after every dump, even after you have your problem sorted. 

Try Hot Water

Another option that might help unclog an RV black tank? Hot water. Boil water on the stove and pour it down your tank. This might be enough to break up any clogs and get your wastewater moving once again. 

Use a Snake

A sewer snake or even just a broom handle (that you don’t mind tossing when all is said and done) could also work to unclog an RV black tank. Simply stick the tool down the toilet and use it to move things and around and (hopefully) get rid of the clog.

You will want to be careful when using this method so you don’t damage your plumbing. Additionally, you’ll need to be prepared to deal with a gross smell.

Go for a Drive

Taking the RV for a drive could also work. This gets the water in the black tank moving, mixing things up and potentially breaking up whatever solids are causing the problem. Some people will also dump a bag of ice down the toilet before driving. They claim the ice helps break everything down.

RV Black Tank Flush Kit

Our final DIY suggestion? Flush your black tank out. 

If you don’t have one built into your rig, grab an RV black tank flush kit. This simple device twists onto your RV dump pipe. After attaching it to the pipe, you will attach a sewer hose to the other end, add a water hose to the back-flush device, open the RV black tank valve, turn on the water, and allow the strong spray of water to break up your clog. 

Please note that you will need to be careful flushing your tank when a clog is involved. If flushing doesn’t work right away, you might just end up with too much water in your black tank and a stinky mess inside of your RV. 

Call in the Pros

Once in a while, you’ll find that none of the DIY methods will be enough to get rid of a particularly stubborn RV black tank clog. If you’ve tried all of the above and are still stuck with a full black tank that just won’t dump, it might be time to call in the professionals.

That’s right, there are professional holding tank cleaners, and they can unclog an RV black tank quickly! To find someone who can help, simply do an internet search for “RV black water tank cleaning service near me”. This should help you locate an RV black tank cleaning pro that will get your RV plumbing system back up and running asap. 


Avoiding a Clogged RV Black Tank in the Future 

Once you’ve dealt with a black tank clog once, you aren’t likely to want to do that again. Fortunately, there are plenty of things you can do to avoid clogged black tanks in the future. 

Keep the Tank Closed 

First and foremost, it is incredibly important that you keep your RV black tank valve closed until the tank is nearly full and ready to be dumped, even when you have full hookups. An open valve allows liquids to flow out of the tank right away, leaving solids behind to dry out and build up. You don’t want that.

By keeping the liquids in the tank with the solids as long as possible, you give everything a chance to break down and give the solids motivation to leave the tank with the rush of water when it comes time to dump. 

Use RV-specific Toilet Paper

Most regular toilet paper just doesn’t break down right in an RV black tank. For this reason, it is a good idea to always use RV-specific toilet paper, which is made to break down in the tank, preventing buildup that could cause a clog. 

Some RVers even go so far as to avoid putting toilet paper in the tank at all, opting instead to put it in a small trash can that gets taken out regularly. 

Always Use an RV Black Tank Treatment

We mentioned above that it’s a good idea to find a black tank treatment you like and add it to your tank after every dump. Not only will this help prevent buildup and clogs, it’ll also help if your RV black tank stinks—a major bonus, if you ask us.

Flush Out Your Black Tank Regularly

Last but not least, we highly recommend using an RV black tank flush kit like the one linked above (or the flush kit built into your RV) to do an RV black tank flush after every dump. Like the RV black tank cleaner, this will help remove buildup, preventing clogs and smells from happening down the line. 

Hopefully this helped you unclog an RV black tank and get rid of a stinky problem. Be sure to use the precautionary tips as well, as you should be able to avoid future RV black tank clogs and continue to travel in comfort.

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