How to Get Rid of Sewer Smell in Travel Trailer: Common Causes and Solutions

There’s nothing worse than opening the door to your travel trailer and being hit with an unpleasant sewer smell.

While it’s a common issue for RV owners, it’s certainly not one you want lingering around during your road trip.

Understanding the causes of this foul odor and learning how to fix it will help you enjoy a fresh and clean travel environment.

In this guide, we’ll explore the common reasons behind sewer smells in travel trailers and provide practical steps to eliminate and prevent the odor from returning.

Common Causes of Sewer Smell in a Travel Trailer

1. Full or Overfilled Black Tank The most common source of sewer smells in travel trailers is an overfilled black water tank (the tank that holds your toilet waste). When this tank gets too full, gases and odors can escape back into your RV, leading to that telltale sewer smell. Regularly emptying your black tank is essential to keeping odors at bay.
2. Dry P-Trap Your travel trailer’s sinks and shower have P-traps that hold water to block sewer gases from coming up through the pipes. If these traps dry out due to infrequent use, the barrier is lost, allowing unpleasant odors to enter your trailer. This is a common issue if your trailer has been sitting unused for a while.
3. Clogged or Dirty Tank Vent Your black and gray tanks are vented to the outside of your RV through a vent pipe. If this vent becomes clogged with debris, leaves, or even bird nests, sewer gases can’t escape properly, and the smell may back up into your RV.
4. Faulty Toilet Seal The toilet in your travel trailer is sealed to prevent odors from escaping the black tank. Over time, this seal can wear out or become loose, allowing sewer gases to seep into your RV’s living space. A damaged or dried-out toilet seal is a common source of unpleasant smells.
5. Leaking or Damaged Tank In rare cases, a leak or crack in your black or gray water tank can lead to sewer smells in your travel trailer. If you notice a persistent smell despite following all other maintenance steps, it’s worth checking for leaks.
6. Improper Tank Chemicals RV holding tanks require special chemicals to break down waste and control odors. If you’re not using the right tank treatment or if you’re using too little, it can lead to waste buildup and unpleasant smells.

How to Get Rid of Sewer Smell in a Travel Trailer

1. Empty and Clean Your Black Tank Regularly

The simplest and most effective way to prevent sewer smells is to empty your black water tank frequently. Here’s how to do it properly:

• Empty when needed: Don’t wait until the tank is overfilled. Empty the tank when it’s around two-thirds full to avoid odor buildup.
• Flush the tank: After draining the black tank, flush it with clean water to remove any leftover waste or residue. Some RVs have a built-in tank flush system, but you can also use a hose to do this manually.
• Use the right chemicals: Add RV-approved holding tank chemicals after each tank dump to help break down waste and control odors. Make sure to follow the manufacturer’s instructions on dosage.

2. Keep Your P-Traps Full

If your sinks or shower haven’t been used recently, the water in the P-traps may have evaporated, allowing odors to escape. The fix is simple:

• Run water down your sinks and shower for a few seconds to refill the P-traps.
• Consider adding a bit of mineral oil to the traps to slow down evaporation, especially if you plan to leave your RV unused for a while.

3. Check and Clean the Vent Pipe

A clogged or blocked vent pipe can prevent sewer gases from venting outside, causing the smell to back up into your RV.

To clean the vent:

• Access the roof of your travel trailer where the vent is located.
• Use a garden hose to flush out any debris or blockages. You can also use a long, flexible brush to clean the vent pipe.
• Ensure the vent is free of obstructions and that air can flow through easily.

4. Inspect and Replace the Toilet Seal

If your toilet seal is leaking or worn out, sewer smells can escape from the black tank.

Here’s how to check and replace it:

• Check around the base of the toilet for any signs of leaks or wear in the seal.
• If the seal is dry, apply a silicone-based lubricant to help it maintain its effectiveness.
• If the seal is damaged, you may need to replace it. Toilet seals are inexpensive and can be found at most RV supply stores.

5. Use Proper Tank Chemicals

Using the right chemicals is key to breaking down waste and controlling odors.

Here’s what to look for:

• Choose an enzyme-based or formaldehyde-free tank treatment designed specifically for RV black tanks. These chemicals help break down solids and reduce odors.
• Follow the dosage instructions carefully, and be sure to add treatment after each tank dump or every few days during use.

6. Check for Leaks or Damage

If you’ve followed all the steps above and the sewer smell persists, you might have a leak in your black or gray tank.

Check for any signs of damage, cracks, or leaks under your trailer or around the tanks.

If you find a leak, you may need to take your travel trailer to a professional for repair.

Preventing Sewer Smell in Your Travel Trailer

1. Regular Maintenance Stick to a routine maintenance schedule for your tanks. Regularly empty, flush, and treat both your black and gray tanks to keep them clean and free of odor buildup.
2. Ventilation Ensure your RV’s vent pipes are always clean and functioning properly to allow sewer gases to escape. Proper airflow in your RV’s interior can also help minimize any odors.
3. Use the Right Toilet Paper Use RV-specific toilet paper that is designed to break down easily in holding tanks. Regular toilet paper can cause clogs and lead to odor issues over time.
4. Stay Hydrated (Your Tanks, That Is) After dumping the black tank, always add a few gallons of water back into the tank. This will help prevent waste from sticking to the bottom of the tank, which can cause odors to linger.

Final Thoughts

Sewer smells in your travel trailer can be a frustrating issue, but with regular maintenance and a few simple fixes, you can keep your RV smelling fresh and clean.

From emptying and cleaning the tanks regularly to checking the seals and vents, taking the time to care for your RV’s plumbing system will ensure that your travels are odor-free.

By following these steps, you’ll be able to enjoy your trips without worrying about unpleasant smells, and you can focus on making the most of your travel adventures.