How to Unclog an RV Black Tank: 3 Types (What to Avoid)
RV black tanks hold waste and toilet paper, but they become clogged with debris that builds up with use. A clogged black tank can cause unpleasant odors, leaks, and even system damage.
To unclog an RV black water tank: use specialized enzyme-based black tank cleaners, a black tank wand, and a plumbing snake. You can also use a high-pressure water jet or introduce more water (toilet or external port). Regular maintenance will prevent most tank clogs.
When you repair clogs, you’ll use tools and chemicals to break up the debris. There are some methods to avoid that are covered at the end of the post. If you can’t clear the clog on your own, contact a professional.
Read on to learn how to unclog an RV black tank and keep it running smoothly.
3 Main Types of RV Black Tank Clogs
If you’ve ever had a clogged RV black tank, you’re not alone. You can take steps to clear the blockage and get your black tank up and running.
You can encounter several types of black tank clogs in your RV, including:
- Organic clogs
- Inorganic clogs
- Grease clogs
These clogs can be in the tank or pipes. Another common clog is when solids solidify which results in a compacted tank.
Different issues cause these problems, so you need to understand how to fix them, whether you’re planning your next trip or already on the road.
Here’s how to unclog an RV black tank.
1. Organic Clogs
Organic clogs are the most common type in RV black tanks. The buildup of waste, toilet paper, and other organic materials in the tank became too much for the water to wash away, so a clog developed.
You might cause organic clogs by using too much toilet paper, flushing inappropriate items down the toilet, not using sufficient water, or not adequately maintaining the tank.
To fix an organic clog, try the following steps:
- Use an enzyme-based black tank cleaner to break down waste and toilet paper and make it easier to flush out of the tank. Fill the tank with water and let the cleaner sit for several hours to break down the clog.
- Make use of a black tank wand, a long, flexible rod with a nozzle on the end that connects to a hose. It can reach deep within the black tank to break up and flush out clogs. But be careful—it’s quite powerful and can damage the tank if not used correctly.
- Think about using an RV macerator pump. The device grinds waste and toilet paper into small pieces, making it easier to flush through the discharge valve.
- Connect the sewer hose to the black tank’s discharge valve and flush the tank with a steady stream of water.
To avoid organic clogs, including poop pyramids, make sure you use enough water with each flush.
Here’s our full guide to flushing your black water tank on your RV.
2. Inorganic Clogs
Materials such as rocks, gravel, and other debris create inorganic clogs in RV black tanks. These clogs form when people flush inappropriate items down the toilet or fail to maintain the tank properly.
Organic clogs are easier to remove than inorganic clogs, but there are a few steps you should take to fix them without much trouble.
- Check the Discharge Valve: Ensure there’s no debris caught in the discharge valve. If there is, remove the valve and clean it thoroughly to remove any blockages.
- Use a Plumbing Snake: A plumbing snake is a long, flexible rod with a spiral end. You can insert it into the tank to break up and remove the blockage.
- Use a High-Pressure Water Jet to break up and flush out the clog. These tools are useful for pushing out clogs caused by hard materials such as rocks and gravel.
- Use a Specialized Chemical Dissolver: Some chemical dissolvers dissolve inorganic materials like rocks or gravel. Be careful when using these products since they’re harsh. They can harm your skin and damage the tank if you’re not cautious. They’re also bad for the environment, so dispose of the chemical wastewater safely.
Here are three methods for dumping your RV waste at home.
3. Grease Clogs
The accumulation of grease and other oils in the tank causes grease clogs in RV black tanks. These clogs form if people flush inappropriate items down the toilet.
Failing to maintain the tank also lets debris build up into an immovable blockage. Grease clogs are difficult to remove and can cause odors.
To clear a grease clog in an RV black tank, try the following steps:
- Use a grease dissolver that breaks down grease and oils.
- Connect the sewer hose to the black tank’s discharge valve and flush the tank with a steady stream of water.
- Make use of a black tank wand, which is a long, flexible rod with a nozzle on the end that connects to a hose. It’s intended to reach deep within the black tank to break up and flush out clogs, including grease clogs. Be cautious when using this tool, as it’s quite powerful and may cause gross overspray if not used correctly.
When a black tank sensor shows full when empty, it can be caused by a clog.
7 Methods to Avoid When Clearing Clogged RV Black Tanks
There are a few methods that are not recommended for clearing clogs in RV black tanks.
Some of these methods can be dangerous and can cause damage to the RV’s plumbing system. Others are simply ineffective and will waste your time.
- Don’t mix chemicals and cleaners. You’ll want to avoid mixing bleach with ammonia or other cleaners.
- Baking soda: While this can help with odors, it won’t do anything with clogged black water tanks.
- Ice or Boiling Water: While this might seem like a good idea, it will have minimal to no benefit. With ice, the idea is to dump a bunch of ice cubes in the tank, then drive the RV allowing the cubes to agitate the clog. And hot water will only help if the clog is because of ice.
- Dish soap: While some brands of dish soap are famous for cutting grease, this isn’t what your black water tank needs. It needs to be broken up – either physically with a pipe snake or with an enzyme-based tank treatment.
- Using harsh chemicals such as drain cleaners can be harmful to the environment and can also damage the tank and the RV’s plumbing system. They also can be hazardous for the people who handle them.
- A high-pressure washer can be very effective at breaking up clogs, but it can also damage the plumbing system if not used properly. You could also get a splashback of black water on your face or bystanders.
- Using a plunger to clear clogs in RV black tanks is ineffective because the clogs are typically located deep within the tank. It’s too far for you to reach with a plunger.
Ignoring a clog in an RV black tank can result in unpleasant odors, leaks, and even system damage.
It’s preferable to prevent clogs instead of needing to fix them. Regular maintenance and eliminating inappropriate items from the toilet can help prevent clogs in the first place.
It’s important to always use the appropriate tools and methods when trying to clear clogs in RV black tanks and to seek professional assistance if you are unable to clear the clog yourself.
More reading: How to winterize and dewinterize your RV.
Avoiding Clogged Black Water Tanks
Properly maintaining your RV wastewater tank can help prevent clogs. Check guidance in specific areas where you travel to understand how to properly dispose of your waste.
Each state and province has legal requirements to protect its land and citizens, and some counties and national parks have their own regulations. Stay informed and follow the guidelines.
Unclogging an RV black tank can be a difficult task, but it’s necessary to keep the RV running properly. Organic clogs, inorganic clogs, and grease clogs are the most common types of clogs in RV black tanks.
Your Turn
Always follow proper wastewater disposal guidelines before and after you eliminate the clogs in your RV black tank. You want to empty the tank in a safe place to prevent making people sick, but you also need to check the environmental standards.
How did it go for you? I would like to hear how you cleared your clogged RV black tank.
