How To Unfreeze Sewer Pipes In An RV

by Jun 18, 2022Blog, RV

One thing you don’t want to deal with during a cold-weather RVing adventure is having your pipes freeze up. Unfortunately, it happens all the time.

In many cases, treating frozen sewer pipes in an RV is not too difficult if you know what you’re doing. Here are some helpful tips for dealing with this frustrating issue.

How To Unfreeze Sewer Pipes In An RV 1

Before treating frozen RV sewer pipes, you should know that you must be careful not to damage them. 

It’s important to know that different types of sewer pipes and lines require different treatments. You should not use heat sources directly on the pipe, as this could cause damage. You also shouldn’t use chemicals since they can further corrode the pipes.

Do not try to force open your frozen sewer line if it has been frozen for a long time since this can cause severe damage and may even break off sections of the line.

Do not use hot water or boiling water on your frozen sewer pipe because it could create dangerous fumes in your RV if you use propane gas or electric power for heating purposes.

Also, avoid using propane torches on any part of your RV’s plumbing system; doing so could cause explosions or fires due to the fuel lines near the tanks themselves (which might have become damaged by freezing temperatures). 

Finally, never use blow torches on any part of your RV with an installed sewer system—they’re just too flammable!

The most critical thing to remember is never to use a heat source in direct contact with the pipes or lines.

This includes blow dryers, heat guns, propane torches, propane heaters and any other device that could heat the pipes. Heat will cause them to expand quickly and then contract once the water inside freezes again later on. This can cause damage to your RV’s plumbing system if not done correctly.

An electric heater works best for thawing frozen sewage lines because it uses indirect heating rather than direct contact methods like those mentioned above.

An electric heater will slowly raise the temperature of your RV’s wastewater tank until it reaches a point where it no longer needs to be heated up again when it freezes over due to low temperatures outside during winter months. 

If you have a flexible sewer hose, you can treat it by running hot water through it until it’s unfrozen. Don’t use a heat source in direct contact with the pipes or lines, as this can damage them. Don’t use chemicals or acids to treat the pipes either. The only thing that should touch the frozen pipes is hot water.

If your RV has separate black and gray tanks and their hoses are different, you’ll need to freeze-treat each one individually before connecting them.

If they’re connected, however, they’ll need to be treated together using both hoses at once. You can do this by disconnecting one of them from its tank and holding it under warm running water until most of the ice has melted away.

Then reconnect both hoses together so that all of their contents drain into each other equally (you don’t want just gray water draining into one end). 

Finally, remove any remaining clogs in both lines with a plunger or plumber’s snake tool before reconnecting them back up!

If your RV has rigid PVC sewer pipes, pouring hot water over the end may help melt some ice inside

If your RV has rigid PVC sewer pipes, pouring hot water over the end may help melt some ice inside—but only if they are above freezing temperature.

The water should be hot enough to melt the ice but not so hot that it will damage the pipe. This is why it’s essential to ensure that your RV is above freezing temperature before trying this method.

Using Electric Heating pad

How To Unfreeze Sewer Pipes In An RV 2

To unfreeze an RV sewage tank using an electric tank heater, first locate the tank and ensure that it is easily accessible. Next, clean the area around the tank and remove any debris or obstacles.

Once the area is clear, attach the electric tank heater to the tank using the included mounting straps or adhesive. Be sure to follow the manufacturer’s instructions for proper installation.

Once the heater is securely in place, plug it into a nearby electrical outlet and turn it on. The heater will begin to warm the tank, slowly melting any frozen sewage inside.

It may take several hours for the tank to fully thaw, so be patient. Once the tank is fully thawed, the heater can be turned off and removed. It is important to properly maintain and store the electric tank heater to ensure it is ready for use in the future.

This is much more likely to happen during cold weather camping with a travel trailer than with a motorhome

We’re not trying to scare you here; we just give you the facts. The problem is that frost and snow can build up on your trailer’s underbelly, which then melts and freezes again when temperatures drop.

This is much more likely to happen during cold weather camping with a travel trailer than with a motorhome since the underbelly of a motorhome is usually insulated from the elements, but travel trailer underbellies usually are not.

Additionally, suppose your sewer hose isn’t flexible enough (like most RVers’ hoses today). In that case, it can also freeze, especially if there’s snow on top of it or around it.

Keep pets and belongings away from the area where you’re working

Whatever method you use, it’s very important to keep people, pets and belongings away from the area where you’re working, as chemicals and hot water can cause injury if they splash on you or other living things or other things. It’s also a good idea to wear safety glasses when handling chemicals and tools that may cause injury.


Suppose you’re unsure what kind of sewer pipe or line you have and aren’t confident in your ability to keep it from getting damaged. In that case, you might want to call a professional plumber like an RV service person.

They can also advise on whether you should try a particular fix yourself. In some cases, they may even be able to recommend a less risky option than the ones we mentioned above. And if, at first, you don’t succeed with your DIY attempts to fix frozen pipes on your RV, remember that you can always try again another day.