How Do I Unfreeze My RV Black Tank? (Step by Step)

How Do I Unfreeze My RV Black Tank

Have you ever wondered how to unfreeze your RV black tank or how to thaw frozen black tank? Well, look no more. We´ve got you covered.

RVing year-round is a great way to experience all of nature’s wonders – rain, sun, or snow.

If you RVing in the winter, you have to do a few extra steps to ensure that the entire RV, including the holding tanks, is winterized.

Unfortunately, many people do not know they have to winterize their holding tanks before winter sets in. If you are one of these people, you might have a frozen black tank as a result.

Given that the black tank holds a number of unsightly items, the last thing you want is for the tank to freeze.

So, how to unfreeze your RV black tank? To unfreeze your RV black tank, just follow the steps below, which include:

1.         Move The RV

2.         Put On Your Gloves And Safety Goggles

3.         Wipe Away Items On The Holding Tank

4.         Blow Dry The Black Tank

5.         Flush Out The Tank

6.         Winterize

This article will provide you some basic ways to unfreeze an RV black tank, as well as tips for winterizing your RV holding tanks so this doesn’t happen again. Let’s get started.

How To Unfreeze An RV Black Tank

A frozen RV black tank is incredibly troublesome. Not only can it make using your RV annoying, but it can also force you to do work you never wanted to do, namely dethaw a tank with waste and other disgusting materials.

Luckily, unfreezing an RV black tank is a bit easier than you may expect.

1.    Move The RV

To begin dethawing your RV black tank, it’s best to move the entire RV to a protected space with temperatures above freezing.

Remember, freezing is 32 degrees Fahrenheit or 0 degrees Celsius. A garage or some other enclosed area should do the trick.

2.    Put On Your Gloves And Safety Goggles

Now that your RV is in a more temperature-appropriate area, put on your gloves and safety goggles. Because black tanks contain such hazardous waste, you want to protect yourself.

You may also want to opt for a mask, but this may not be necessary. It is totally up to you.

3.    Wipe Away Items On The Holding Tank

With your gloves and goggles on your body, grab your rag to simply wipe down the holding tank. Dirt and insects may be on the outside.

A dry rag will likely work for most people. If you have mud or dead bugs on the tank, you might want to saturate the rag with water first.

4.    Blow Dry The Black Tank

Now, it is time to start unfreezing the holding tank. Grab a blow dryer and start thawing out the tank. Hold the blow dryer between 6 and 12 inches away from the tank. Pass the blow dryer over the entire area slowly in a back and forth motion.

Do not keep the blow dryer targeted at one location for too long because this can cause the tank to melt.

As you are thawing out the tank, look for any cracks or leaks in the tank or waste line. Frozen items expand.

This can force the tank itself to start falling apart. If you notice cracks and other broken pieces, you will need to repair them or get a whole new tank.

You will need to use the blow dryer for quite some time. It may be best to start at the upper part of the tank and work down. Repeat until you can open up the termination valve and hear the frozen contents evacuating the tank.

As you blow dry the black tank, continue to wipe down the tank with a dry rag. As the tank thaws out, condensation will build-up.

Wipe down the tank to keep everything clean and prevent water damage. Wiping down the tank can also make it much easier to determine if there is a leak or crack in the tank.

Read also: Do I Really Have To Use RV Antifreeze?

5.    Flush Out The Tank

As the contents start thawing out, you will hear them evacuating. Continue blow drying the black tank until all of the contents are evacuated.  

You won’t need to do anything extra to flush out the tank, but make sure it is properly flushed out before going on to step 6.

6.    Winterize

Finally, the last step for unfreezing a black tank is to winterize it. The most important step for winterizing the black water tank is to add antifreeze to it once everything has been flushed out.

We will go over winterizing holding tanks in more detail next.

Read also: Can You Mix Bleach and RV Antifreeze? (Flushing Out Antifreeze)

If you notice that other holding tanks are frozen, go through steps 1 through 6 to unfreeze them as well.

All holding tanks will be thawed out in the same way, but you likely won’t need to be as careful with the thawing process as you would with the black tank.

DEFROSTING THE RV HOLDING TANKS >> Check out the video below:

Tools You Need For Defrosting Your RV Holding Tanks

•           Disposable gloves

•           Goggles

•           Blow dryer

•           Rags

How To Winterize Your RV Holding Tanks

Whether your holding tanks have frozen, or you have a new holding tank in your RV, you need to winterize the tanks before cold weather sets in.

Winterizing the tanks can save you a whole lot of time and effort in the future.

Winterizing RV holding tanks always includes a non-toxic antifreeze. If you expect your RV to be in temperatures that are incredibly cold, you can also add insulation or heating systems to keep the tanks in working order.

Here is more information for winterizing your RV holding tanks:

1.    Antifreeze

Antifreeze is the number one way that RVers keep their holding tanks from freezing. Select a non-toxic antifreeze that is made for RVs specifically.

Often, RV antifreeze is colored pink to denote its non-toxic nature. Green antifreeze, on the other hand, is toxic.

To add antifreeze to your holding tanks, make sure that the tank is completely empty. If you went through the dethawing process, you should likely already have this step down.

Also, close the dump valves. Add a couple of quarts of the antifreeze to the black water tank by pouring it down the RV toilet.

If you need to add antifreeze to your other holding tanks, simply pour it down the shower or tub drain. This will allow it to go to the gray holding tank.

The exact amount of antifreeze you add will depend on the size of your tank.

Read also: Does RV Antifreeze Go Bad or Expire? Shelf Life of Antifreeze

2.    Insulation

If your black holding tank froze even after you added antifreeze, you might need to add some more protection to the tanks.

Adding insulation around the tanks is a relatively affordable and effective way to keep the tank thawed out.

When using insulation, add it around all sides of the holding tanks. This may be a bit difficult, depending on how much space is open around the tanks, but it should be doable in most RV designs.

You can add something like a blanket around the tanks to add a bit more warmth and insulation.

3.    Heating Systems

In the most extreme scenarios, antifreeze and insulation may not be enough. If that’s the case for you, you can add a heating system to prevent the tank from freezing.

For example, you can add a heater blanket around the tank. This will both insulate and heat it at the same time.

You can also add holding tank heating pads. Using them in combination with other techniques is the most effective option.

Simply peel and stick these heating pads to apply them to a tank. This creates a user-friendly, safe, and thermostatically controlled heating option for your tank.

Read also: Can You Put RV Antifreeze in a Water Heater? (FACTS You Need to Know)

Heat Tape For RV Holding Tanks (heater pads)

To keep your RV holding tank discharge pipes stay warm or to prevent your RV holding tank for freezing, you can also use heat tape or heater pads.

To apply, take the heat tape off the roll and fasten it to any pipes where water flows.

Heat tapes are relatively cheap, you can purchase them at most home improvement stores or just follow the link to Amazon to check the current price.

Protect The RV Water Tank From Freezing with RV holding tanks heat pads! >> Check out the video below:

Thaw frozen Black Tank FAQs

Let’s close out this page about how to thaw frozen RV holding tanks with answers to some of your most frequently-asked questions about them! How to thaw frozen RV sewer line

How To Keep RV Pipes From Freezing While Camping

To keep RV pipes from freezing while camping, just follow the steps below:

–       Use heat tape on pipes and hoses

–       Warm your internal plumbing

–       Use the internal freshwater tank

–       Use a space heater

–       Add antifreeze

–       Dump tanks wisely

What is a black water tank?

A black water tank is what collects the waste from your toilet. It will typically be located underneath the RV carriage.

Next to it should be the gray water tank, which holds waste from sinks and showers. Only flush waste, biodegradable enzymatic products, and septic-safe toilet paper into the black water tank.

How do I clean my RV black water tank?

Cleaning your RV black water tank is required for proper maintenance. For best results, it’s always a great idea to add RV black water treatment to the tank at the beginning of every camping trip.

Add the commercial product with about a gallon of water for optimal usage.

Be sure to clean out black water tanks after trips and before storing your RV too. Use a commercial product, as well as add soapy water to the RV tanks.

You can do this by adding soapy water down the toilet and tub drains.  

RV black water tanks can get clogged. To prevent this from occurring, make sure to maintain the tank properly and only use RV-safe toilet paper.

Do not flush anything else down the toilet. If you notice a clog in the black water tank, fix it immediately.

What do I need to winterize on my RV?

RVs need to be winterized before cold weather sets in. So far, we have talked about winterizing holding tanks, but more items inside your RV need to be winterized.

For example, water filters need to be removed and bypassed. Similarly, you need to drain your water heater and water lines, as well as bypass your water heater.

Finally, you need to add antifreeze to your RV. You want to add this antifreeze throughout all of the water lines so that nothing freezes.

If you are unsure how to winterize these parts in your RV, you can always hire a professional to do the job for you.

When should I winterize my RV?

You want to winterize your RV before real cold weather sets in, but you don’t want to do it too soon either. For best results, you should winterize your RV before September ends.

Winterize your RV at the end of August or the beginning of September for the best results.

Final Thoughts

If you do not properly winterize your RV system, it can easily freeze up, causing a lot of issues down the road. This is especially true of a black water holding tank.

If your black water holding tank is already frozen, there are things you can do about it.

The easiest way to unfreeze a black water holding tank is to use a blow dryer. Remember: you must point the blow dryer at the holding tank, but constantly move it around.

Focusing it on one location for too long can lead to a melting tank. As you are unfreezing the tank, look for any cracks or leaks.

Once you have thawed out the black water tank, you need to winterize it and any other tank. This primarily involves antifreeze, but you may also want to add insulation or some heating system.

Properly winterizing the tank after you have thawed it out can help prevent yourself from being in the same situation down the line.


Mike Gilmour

Hi, I'm Mike, co-founder, and editor of RV and Playa. My passion is traveling (with my RV) and enjoying the day at the beach (Playa)! Well, I originally created this blog as a way to share what I've learned by experimenting with the RV lifestyle, and I want to help others develop in life through new skills and opportunities.

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