FTC Disclosure: I get commissions for purchases made through some of the links in this article for more information, visit our Advertising Disclosure Page.

You can subscribe to the Everything About RVing YouTube Channel for some great videos about RVing

There is a Sewer Smell in Our Motorhome While Driving

by Dawn
(Traveling in Texas)

How to Get Rid of the Sewer Smell in Your RV

How to Get Rid of the Sewer Smell in Your RV

40" Fleetwood Revolution RV has sewer smell only while driving how do I fix it?

ANSWER: Hi Dawn the bad news is that this is a common problem that RVers experience. The good news is that in most cases there are some simple steps you can take to stop the sewer smells from entering your motorhome while going down the road. I am going to assume that you are using a good RV Sewer Treatment like Happy Campers RV Holding Tank Treatment. Below I have listed the most common causes and remedies for a "Smelly Motorhome".

No Water in P-Trap Each of the sinks and showers/tubs in your RV have P-Trap (see picture at the top of this page) just like the sinks and showers/tubs in your house. The curved part of the P-Trap is designed to hold water and prevent holding tank fumes from entering the RV from the drain. The problem is if there is no water in those p-traps holding tank gases could be sucked into the motorhome through the dry drain.

If you drive your motorhome with windows or vents open it can create suction in the RV almost ensuring that holding tank fumes will be sucked into the motorhome through a dry sink or shower/tub p-trap.

Solution: Before traveling make sure that you dump some water in each of the sink and shower/tub drains in your motorhome. If this does not cure the problem, move on to the next step.

Camping World
Up to 70% off Clearance - While Supplies Last!

Bad Air Admittance Valve You may have Air Admittance Valve on your RV's Sinks (see picture at the top of the page). In some motorhomes, an Air Admittance valve is used on RV sink in place of having a roof vent on the sink. The way an air admittance valve is supposed to work is when you run water in the sink you create a
vacuum which opens the valve on the air admittance valve to allow water to freely flow into your RV's holding tank.

Occasionally these valves get stuck in the open position allowing holding tank gases to enter the motorhome.

Solution: To fix this problem you need to install a new air admittance valve on the affected sink. The air admittance valve will be under the sink and attached to a stub from the output side of the sink drain. You simply unscrew the old valve from the pipe and screw on the new valve. If this does not cure the problem, move on to the next step.

Over 1,500,000 successful roadside rescues—Good Sam RV Emergency Road Service

Replace Sewer Vent Cover/s: In some cases, it may be necessary to replace the factory vent covers on your RV with ones that will effectively draw holding tank odors out of the tank to the outside of the RV while traveling.

Solution: One of the most effective and highly rated of these vents is the Camco Cyclone Rotating Sewer Plumbing Vent manufactured by Camco (see picture at the top of this page). The Cyclone Sewer event costs less than $25.00 and can be a do-it-yourselfer installed. Look at the video below to see how the vent works and how easy it is to install.

Again the tools you will need are:

* Utility and Putty Knife
* 100% Silicone Caulk
* Drill with a 3/32 drill bit
* Phillips Screwdriver

Other Less Common Causes of This Problem:

* A bad seal on the RV's toilet
* A broken, cracked or disconnected holding tank vent pipe
* A cracked or leaking holding tank
* A cracked or broken pipe under a sink, shower/tub or toilet
* RV house batteries could be causing the sewer like smell if they are overcharging or if the electrolyte levels low

I hope that this information has been helpful to you.

Comments for There is a Sewer Smell in Our Motorhome While Driving

Average Rating starstarstarstarstar

Click here to add your own comments

We got rid of the smell
by: Dave White

Happy Camper Organic Holding Tank Treatment

We had that same smell while driving. I ended us using a product called Happy Camper Organic Holding Tank Treatment. This stuff works. No odor seriously even when we dump the stuff is amazing. We are not affiliated with the product at all just happy users.

Check it out on Amazon and be sure to read the reviews. Finally something that works.

Click here to add your own comments

Return to Ask an RV Question.