How To Unclog RV Black Tank

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Waste and toilet paper are usually responsible for your black water tank clogging. Whether or not it’s equipped with sensors, you have to service the tank every once in a while. But, even if the sensors alert you when it’s time to clean up the mess, they won’t tell you what exactly the problem is.

If you’re wondering how to unclog a RV toilet holding tank. Here are a few methods that can help you unclog and clean your RV toilet holding tank.

Necessary Items and Tools

Some of these items are needed for some hands-on unclogging methods:

  • Drill
  • Water hose
  • Clear hose connector
  • Toilet snake
  • Chemical cleaning agents
  • Water piping connector, 5 ft. long

Step-by-Step Guide

Cleaning the tank

One of the best ways to clean a black water tank is with septic system powder treatment. Not only does this help disintegrate even the slimiest waste, but it can also provide a protective coating that might prevent future clogs.

Wipe down the line

Hardened waste materials often build up in and around the waste water line, which connects the toilet to the holding tank.

How to clean it? By using a toilet snake or an auger. It’s best to use a manual model to avoid any accidental piercing. Insert the auger and push slowly down the length of the pipe. Gently poke around when you feel any resistance.

An alternative to this would be to fill the black tank with a mixture of water and liquid soap to about half capacity. Drive your RV around, preferably on some rough terrain to allow the mixture to dislodge any hardened stuff.

After that, pass the water through the pipes and let the tank sit. Flush the line after a few hours.

Test the tank valves

After cleaning the line and the tank, you might want to check the valves to make sure they’re working properly. Sometimes this may be enough to solve your clogging.

Use a chemical cleaner

Some people prefer going the chemical-free route. However, chemical cleaners will almost always get the job done. It’s important to consider them especially if you have serious clogging issues.

Check online for some of the most popular chemical cleaners for RV black water tanks. Then follow the instructions on the packaging. Some cleaners are used as drop-ins while others need to be mixed with hot water and poured down the toilet.

The methods may differ by quite a bit.

The water hose method

  • This is where you’ll use the drill, the clear hose connector, and the rest of the items.
  • Hook up the clear hose connector to the black water tank.
  • Drill into the connector at the top.
  • Make a hole large enough to fit the water line through, but not any larger as to prevent leaks.
  • Push the water line through the connector until you reach the tank.
  • Run water through the water line. As water starts going in, it will create pressure and move the waste around, causing it to dislodge.
  • Hence the reason for clear connector – so you can tell if the method is working. You can check the water color to see what’s going on.

The ice cube method

  • Pour enough water to fill up about 1/3rd of the tank.
  • Top the other two thirds with ice cubes.
  • Start your RV and hit the road.
  • While driving, the ice cubes should be able to dislodge waste and clumps of toilet paper.

Hire a professional

By now, all your troubles should’ve disappeared. However, if you stuck out, by all means contact a professional. You don’t want to sit on that much waste for too long.

Tips and Warnings – How to Prevent Future Clogs

  • If you clean the tank regularly, you reduce the chances of gunk and debris buildup. It’s important to put this on your calendar, especially if you don’t have any black water tank sensors
  • If you do have sensors, don’t forget to clean them and service them or they will become unreliable
  • Avoid using cleaners that are not intended for RV tanks
  • Switching to biodegradable toilet paper is also a good idea, as it will break down in the black water. Therefore, no more toilet paper clogging the tank or sensors
  • Don’t keep the black water tank empty for too long. It’s recommended to fill it up with water up to halfway so that the solid waste doesn’t just sink to the bottom
  • Performing the additional toilet flush might prevent future clogs
  • Avoid using pressurized air. The extra pressure can make things worse by throwing hardened waste into even harder-to-reach corners of the tank
  • Toilet snakes shouldn’t be used on black water tanks. They’re too small and inefficient overall and might also bust up the tank. Reserve the use of a toilet snake to when you want to manually clean the water line

Why does my RV toilet keep clogging?

Because an RV toilet is different from a regular toilet, many RVs come with a black tank. When you flush an RV toilet, a valve will open and send the waste to the black tank.

A black tank is a holding tank that will usually have a valve where you can open the tank's drain to empty the contents away from your RV. A black tank works by storing your waste until the tank is full. Then, the valve opens, drains the contents into a waste hose, and you can then dispose of the waste.

Will a plunger work on an RV toilet?

Plungers are not the ideal tool for fixing a toilet, but they can be used in a pinch. A toilet plunger does not always clear clogs and may not work on a toilet in an RV.

Closing Thoughts

Probably two of the best things that you can do for your black water holding tank is to switch to biodegradable toilet paper and schedule servicing more often in the future. It’s not the prettiest chore for an RV camper, but it is just as important as servicing the engine or the heating system.

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2 thoughts on “How To Unclog RV Black Tank”

  1. Sometimes, my RV encountered problems that clogged the toilet which made me feel really horrible. I will try to use your way in your post to solve my RV`s problem. I hope that it can work well. Thanks so much!

  2. I used your tips to unclog my RV toilet holding tank and it worked very well, I really satisfied with it. I hope can receive more useful posts from you. Thanks a lot!!


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