Matt Johnson

How to Unfreeze a Frozen RV Sewer Hose

Author: Matt JohnsonPhotos/Graphics: Mike HawthornePublished: Jan 10, 2022Updated: Jan 13, 2024

While many glampers are fair-weather weekend warriors, there’s still a substantial number of full-time people in their RVs. Since winter is upon us, it’s time to start thinking about how to face the cold-weather challenges such as freezing.

If you’re spending time in your RV throughout the winter months, chances are you’ve had to drain out your septic system in freezing conditions. This creates its own unique set of challenges, one of which is a frozen RV sewer hose.

Fortunately, we have some tips that have worked for us in the past every time.

These are tried and true methods that will help you get your septic tank flushed. We’ve even thrown in some tips to help prevent such disasters from happening in the first place.

How RV septic systems work.

An RV has a septic system just like any other home. However, they need to be drained once they’re full due to their size. This means you have some additional valves not found on residential systems and some exposed above-ground sewage lines. In a home, these lines are underground and usually below the frost line.

Full tanks usually aren’t a problem any other time of the year; you find a dump station (located at nearly all RV parks and campgrounds) and dump your gray and black water tanks.

You pull out the sewer hose and attachments, connect to the septic drain on the RV, connect the other end to the in-ground septic tank, and pull the valve. It’s too easy.

But what if the valve is frozen or there’s ice in the RV sewer hose? That’s a problem you don’t encounter with a residential septic system.

What to do if your RV sewer hose freezes.

Frozen Sewer Hose with Black Water
Black water backed up due to frozen sewer hose.

Picture this, you’re a full-time RVer or just a winter-glamper on a chilly weekend, and you have to drain the tanks. You left the hose attached because you drain your tanks every couple of days. Not a problem most of the time, but it’s 20 degrees, and as you pull the drain valve open, you notice the sewage water backs up and stops flowing.

You’re not the first to have a frozen RV sewer hose, so don’t panic.

The only options you have at this point are to hook up a different hose (if you happen to have a spare lying around), wait until the temperature rises to naturally thaw it out, or speed up the process and thaw it out yourself.

One word of advice, though. Don’t touch a frozen sewer hose! If there’s ice in there and you start moving it around, you could break the hose. You’ll have a real mess when the contents begin to thaw out.

How to thaw a frozen RV sewer hose.

The quickest way to thaw a frozen sewer hose is by hot water. Since you’re trying to drain your tanks, that means your gray water is most likely full, and just running hot water in the sink is out of the question. You’ll need another source of hot water.

  1. Avoid touching the frozen hose: Handling a frozen RV sewer hose can cause it to break. I’ve seen it happen.
  2. Use hot water. Disconnect the hose and pour hot water down it. Approximately one gallon of hot water per ten feet of hose is effective. I’m sure more is better, but this works well.
  3. Wait for thawing. After adding hot water, wait a 4-5 minutes for the ice to melt.
  4. Check for water flow. Monitor the end of the hose to see when water starts flowing freely again.

When you see the rush of water, you’re good to go and can start draining your tanks.

Of course, getting to this point is not the most desirable.

As they say, an ounce of prevention is worth a gallon of remedy.

Prevention tips for a frozen RV sewer hose.

Continuous Slope of Septic Hose
This photo shows the continuous slope of the RV sewer hose going into the septic tank at a campground. Photo courtesy of the RV Geeks

The best way to deal with a frozen RV sewer hose is to avoid them. Here are a few practical tips that will help you avoid these situations.

  • Stow your lines between uses. This mainly applies to weekend warriors or those with their RVs in storage. If you don’t need the hose right now, put it away until you need to drain your septic tanks.
  • Pour RV-grade antifreeze in the lines. Full-timers usually keep their hoses connected. If that’s the case, add one or two cups of RV-grade antifreeze in the pipes. Be sure to use antifreeze that’s rated for RVs and marine equipment as it’s usually septic-safe.
  • Make sure there is a constant slope in your lines. If there’s no water in the pipes, there’s nothing to freeze. Maintaining a continuous pitch without any dips in the lines will ensure that the water is out of the lines before it can freeze.
  • Insulate your hose. Cover the hose with insulation material. This can include foam pipe covers or even specially designed RV hose insulating covers. Insulation helps maintain a warmer temperature within the hose, reducing the chance of freezing.
  • Use a heated hose. Consider investing in a heated RV sewer hose. These hoses are equipped with built-in heating elements that keep the contents from freezing, even in very low temperatures.

Prevent freezing at -20℉ — This H&G 15ft heated sewer hose is your solution!

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What about frozen septic tank valves?

Another component that often freezes is the valves under the camper exposed to the elements.

Since you can’t stow these pipes and valves because they’re fixed to your camper, you’ll have to insulate them. We’ve included a quick video showing exactly how to protect your exposed pipes/valves to prevent them from freezing.

Spoiler: It’s super easy to prevent your tank pipe and valves from freezing. All you need to do is wrap them in foil tape, then wrap-on pipe heating cable, then fiberglass pipe wrap.

Keep your sewer hose functioning properly.

Winter glamping in an RV is quite an adventure, but make sure you’re prepared to deal with mother nature.

Of course, the best way is to be ready and avoid frozen RV sewer hoses altogether, but that’s not always possible.

Don’t stress over it if you find yourself in such a situation. Wait it out or pour some hot water in the line, and you’ll be back in business.


Matt Johnson

Senior Content Writer

Matt is an experienced camper and glamping enthusiast with a Master's degree in Wildlife Science from Texas A&M University. Authoring posts for GlamperGear, he shares his wealth of knowledge on picturesque campsites, luxurious accommodations, and the best gear for outdoor adventures. His passion for nature and knack for comfort in the wilderness make him an expert guide for your next camping endeavor.

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