If you’re an RV user, then you know that having a black water tank is essential. However, one common problem with these tanks is that they don’t always drain completely.
If this happens to you, don’t worry – there are ways to fix it! This guide will show you how to properly clean your RV black water tank and get it draining properly again. So read on for tips and tricks that will help you out!
What is an RV black water tank and why is it important
An RV black water tank is a holding tank that stores sewage and waste water from the RV toilet. This waste is typically flushed from the RV toilet; however, it can also come from drains and sink traps.
The black water tank is important because it helps to contain waste and prevent it from contaminating the fresh water supply or ground water. The tank is typically made of black polyethylene, which helps to conceal its contents.
While the tank is typically spacious, it needs to be emptied regularly to avoid overfilling. emptying the tank is typically done at a designated dumping station. The contents of the tank are typically dumped into a septic system or sewer.
The black water tank is an important part of the RV plumbing system. It helps to keep sewage and waste water out of the RV living spaces. In addition, it helps to control odors from the RV toilet.
Without a black water tank, sewage and waste water would have nowhere to go but into the RV living spaces. This could create an unsanitary and unpleasant environment for the RV occupants.
Reasons Black & Grey RV Holding Tanks Clog
So you’ve taken your RV to the dump only to find that the black or grey tank will only empty a few gallons or not at all. This is a common problem for RV owners, especially those who are dumping a used RV or trailer for the first time.
– Overflow
– Clogging of the Drain Valve
– Debris in the Tank
– Wrong Tank Size
– Use of Non-Biodegradable Products
Overflow
One of the most common reasons an RV holding tank clogs is due to overflow. This occurs when the tank is filled beyond its capacity and the water starts to back up into the RV. The first sign of this problem is typically water coming out of the overflow valve. If this valve is not working properly, it can cause the tank to fill up and overflow.
Clogging of the Drain Valve
The drain valve is another common culprit when it comes to clogged RV holding tanks. This valve is located at the bottom of the tank and is used to empty the contents. If this valve becomes clogged, it can prevent the contents from draining out properly. The clog can be caused by debris, such as toilet paper, that gets caught in the valve.
Debris in the Tank
Another common cause of a clogged RV holding tank is debris in the tank. This debris can come from a variety of sources, including toilet paper, feminine hygiene products, and food scraps. If this debris is not removed from the tank on a regular basis, it can cause the tank to clog.
Wrong Tank Size
One of the most common mistakes made when choosing an RV holding tank is selecting the wrong size. It is important to choose a tank that is large enough to accommodate the needs of the RV. If the tank is too small, it will need to be emptied more often, which can lead to clogs.
Use of Non-Biodegradable Products
Another common cause of clogged RV holding tanks is the use of non-biodegradable products. These products, such as baby wipes and cleaning wipes, do not break down like toilet paper. As a result, they can build up in the tank and cause clogs. If you use these products, it is important to flush them down the toilet with plenty of water to help prevent clogs.
Types Of RV Toilet Clogs
Types of RV toilet clogs:
Paper Towel Clogs: These clogs are caused by people flushing paper towels down the toilet. They can quickly cause a blockage in the RV toilet’s plumbing.
Human Waste Clogs: These clogs are caused by people not properly disposing of their human waste. This can cause a nasty smell and attract insects.
Foreign Object Clogs: These clogs are caused by people flushing objects down the toilet that shouldn’t be flushed. This can cause serious damage to the RV toilet’s plumbing.
Hair Clogs: These clogs are caused by people allowing their hair to go down the drain. This can quickly cause a blockage in the RV toilet’s plumbing.
Grease Clogs: These clogs are caused by people pouring grease down the drain. This can cause a slow drain and eventually a blockage.
To avoid these types of clogs, it is important to only flush human waste and toilet paper down the RV toilet. Additionally, it is important to dispose of grease and hair properly. If a clog does occur, it is important to contact a professional to have the RV toilet’s plumbing inspected and repaired.
How Do You Unblock An RV black water tank that’s not draining properly?
An RV black water tank is an essential part of owning an RV. This tank stores all of the wastewater from your RV toilet and sink. It’s important to keep this tank clean and properly maintained so that your RV stays sanitary.
The method you’ll need to utilize to unblock your black water holding tank 100% depends on what type of blockage you found. Here we share with you a few things you can do to try to unblock it.
Step 1: The first thing you should do is check the drainage hose to make sure there is no blockage.
Step 2: If the hose is clear, the next step is to check the valve that controls the flow of water into the tank.
Step 3: This valve may be stuck in the “closed” position, preventing the sewage from draining out. You can usually fix this problem by simply turning the valve to the “open” position.
Step 4: If the valve is already in the “open” position, then there may be a more serious blockage further down the line. In this case, you will need to contact a professional to clear the blockage and get your RV’s black water tank draining properly again.
Step 5: Another step is to remove any debris that may be blocking the valve. You can do this by using a plunger or a wire hanger. Once the debris is removed, use a garden hose to flush out the valve and the tank.
Step 6: If the blockage is still present, you may need to use a chemical cleaner. There are a variety of cleaners on the market specifically designed for RV holding tanks. These cleaners will help to break down any debris and unclog the tank.
Once you have unblocked the tank, it is important to practice proper maintenance to prevent future clogs. This includes using biodegradable products, avoiding non-flushable items, and emptying the tank on a regular basis.
How To Maintain A Healthy Blackwater Tank
Congratulations! Now it’s time to figure out why you had a clogged black tank pipe and learn what it takes to prevent future clogs. There are a few things you can do to maintain a healthy blackwater tank.
The first step is to practice proper wastewater disposal. This means only flushing human waste and toilet paper down the toilet. Additionally, it is important to dispose of grease and hair properly.
The second step is to empty the tank on a regular basis. This will help to prevent clogs and keep the tank clean.
The third step is to use biodegradable products. These products will break down quickly and won’t cause clogs.
The fourth step is to avoid non-flushable items. These items can cause serious damage to the RV toilet’s plumbing.
If a clog does occur, it is important to contact a professional to have the RV toilet’s plumbing inspected and repaired. By following these steps, you can help maintain a healthy blackwater tank.
Why is my black tank filling up so fast?
There are a few possible reasons for this:
1. You may be flushing too much water through your system. Try cutting back on the amount of water you use when flushing your black tank.
2. There could be an obstruction in your black tank that is causing it to fill up faster than normal. Try using a black tank cleaner to see if this clears the obstruction.
3. Your black tank could be leaking. This is a serious problem that should be fixed as soon as possible. Leaks can allow wastewater to contaminate your fresh water supply and lead to serious health problems.
Conclusion
We’ve looked at a few different ways that you can clear a clog from your RV holding tanks. Hopefully, one of these methods has worked for you and you haven’t given up on RV ownership just yet.
Remember, things go wrong with RVs all the time. It’s just part of owning one. But hopefully, being able to go camping or travel the world in an RV makes up for all of the problems you experience along the way.
There are things you can do to properly maintain RV holding tanks so you never experience any clogs. You can read about that in this article here. Thanks for reading and happy travels!
Frequently Asked Questions:
How often should you empty your RV black tank?
You should empty your RV black tank every 3-5 days, depending on how much waste you produce. If you have a large family or produce a lot of waste, you may need to empty it more often. If you are traveling with a group of people, you may need to empty it more often as well.
Does shower water go into black tank?
No, shower water does not go into the black tank. It goes into the gray tank. The black tank is for toilet waste only.
Can you put bleach in RV black tank?
Yes, you can put bleach in your RV black tank. Bleach will help to keep it clean and free of odor-causing bacteria. You should add 1/2 cup of bleach for every 40 gallons of capacity. For example, if your black tank is 50 gallons, you would add 2 1/2 cups of bleach.
What are the consequences of not emptying RV black tank?
If you do not empty your RV black tank, the waste will build up and eventually start to leak out. This can cause a nasty odor and attract insects. Additionally, the weight of the waste can damage your RV’s sewer system.
Emptying your black tank too often
If you empty your RV black tank too often, you may end up wasting water. Additionally, if you have a septic tank, emptying your black tank too often can disrupt the bacteria that break down the waste. It is best to only empty your black tank when it is 1/2 to 2/3 full.

Hi I’m Joiel Borid Creators of RV Outsider. Wild Life’s first camping was started when I’m 8 years old, at the Home Front Yard. Moto of RV Outsider shares my experience, expertise, and knowledge that I learned, and apprises about my next journey. So stay tuned with RV Outsider.