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Why Does My RV Toilet Stink?

It’s one question no RVer ever wants to ask: “Why does my RV toilet stink?”

Nevertheless, most RV owners do find themselves asking this very thing at least once during their RV adventures. In fact, you might be surprised to learn exactly how common stinky RV toilets actually are.

But why is this such a big RV problem? Well, likely because there are so many issues that can cause a stinky RV toilet.

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Possible Reasons Why Your RV Toilet Stink Is Not Going Away

If you’re one of the many wanderers who finds themselves with a smelly RV bathroom, this is the article for you. Below I’ve listed several possible reasons for a bad-smelling RV toilet. I also share how to tackle the issues and hopefully help your RV toilet stink disappear.

Let’s get started!

Reason #1: Bathroom Vent Fan Is on When Flushing

First and foremost, we have to point out something super simple that might just be why your RV toilet stinks.

If you have a bathroom vent fan, it can be tempting to leave it on all the time in order to keep air moving. For the most part, this is fine, and it can even help clear out bad odors. But vent fans pull air out of the rig. Running the bathroom vent fan while flushing the toilet is likely to pull up some not-so-pleasant smells directly from the black tank. 

Have you been running the vent fan while flushing? Does your RV toilet stink only after using the restroom? Try turning the fan off until after you flush. This might solve your problem!

Reason #2: You Have a Dirty RV Toilet

This next issue that might cause your RV toilet to stink is also one of the simplest problems to solve: a dirty toilet. Let’s be honest; it’s pretty easy to get wrapped up in camping fun. Many people forget to give the toilet a good scrubbing now and again.

If you’ve been on a few trips and haven’t cleaned the outside of the toilet, now is the time. Don’t forget to scrub inside the RV toilet bowl, too. A good toilet scrubbing should be your first step in tackling your smelly RV toilet problem. Use a high-quality cleaner and get every crevice.

Reason #3: RV Black Tank Sludge

If cleaning the toilet doesn’t solve the problem, it’s time to look beyond the toilet itself. Your problem might just be in the black tank.

If you leave your black tank valve open all the time, there is a good chance you’ve created a “poo pyramid.” This is a mountain of solid sludge on the bottom of the black tank. It cannot drain because you don’t leave enough liquid in the tank to break it down.

How To Remove Black Tank Poo Pyramid Sludge

If you suspect a black tank poo pyramid, get a tank sprayer wand to get the buildup cleaned out. Then, be sure to always keep the black tank closed. The only time the valve should be open is when you are ready to dump the contents. 

Now, if that doesn’t help, the sides and bottom of your black tank might have developed a layer of buildup. Black tank sludge residue can cause an enormous stink. An RV toilet sprayer wand can take care of this.

Once you’ve gotten rid of the RV toilet stink, rinse the black tank after every dump to keep things fresh. 

Reason #4: Your Black Tank Vent Pipe Is Blocked

If you’ve tried all the steps listed above and your RV toilet still smells, it’s time to inspect the black tank vent pipe on your RV roof.

You should have two vent pipes on the roof of your RV. One allows gases to escape the gray tank. The other releases gases from the black tank. If your black tank vent pipe is blocked, those same gases will back up into the RV toilet instead of the rooftop vent pipe. 

How To Check for Vent Pipe Blockages

First, put a water hose down the vent pipe. Then turn the water on. Let it run for a few minutes. If the water runs down without issue, you either didn’t have a blockage, or perhaps the water stream cleared the blockage. If the water comes back up, try more water pressure or a plumbing snake to get rid of the blockage. 

Reason #5: You Have a Bad RV Toilet Ball Seal

RV toilets use a seal around the ball at the bottom of the bowl. This keeps water in the toilet bowl between flushes. The water works as a smell shield. It keeps black tank smells from entering the RV. But RV toilet ball seals wear out. One sign of a bad RV toilet ball seal is when you wonder, “Hmm, why does my RV toilet stink?

Is Your RV Toilet Bowl Not Holding Water?

A bad seal could very well be the reason you’re getting bad smells in your RV. Fortunately, replacing the seal is inexpensive. It’s an RV maintenance job that’s easy enough for most people to handle on their own. The following clip demonstrates how to replace an RV toilet ball valve seal.

Reason #6: Your RV Toilet Has a Bad Lower Flange Seal

The ball seal isn’t the only toilet RV seal that can wear out. There is also a seal around the bottom of the toilet bowl itself. This sits between the bowl and the pedestal. When it goes bad, water leaks onto the floor after a flush. The leaking RV toilet bowl water could result in a smell. It’s caused by sewer gases that escape through the worn seal.

How To Replace an RV Toilet Flange Seal

Do you see water on the floor after flushing? First, put a paper towel or two around the bottom of your RV toilet. This helps determine if water is leaking from the toilet base and not a water line or a crack in the bowl. If it’s the first problem, watch this video to learn how to replace a lower-flange RV toilet seal.

Reason #7: You Have a Leaky RV Holding Tank Pipe/Fittings or a Cracked Black Tank

This last problem is probably the least likely reason why your RV toilet stink isn’t going away. Unfortunately, it’s also the most expensive to fix. If you’re smelling a stink in one area all the time and you’ve reviewed all of the reasons why your RV toilet stinks, check for a leaky RV holding tank pipe or cracked black tank. 

If your black tank is leaking, you will almost certainly find water on the ground under the tank or in your enclosed underbelly. The stinky RV toilet smell will be strongest outside of the RV. 

And if you’re dealing with a leaking RV holding tank pipe, water might run outside or inside along the RV. Find your holding tank pipe and follow it. Look for water coming from any fittings or places where the pipe bends and connects to the black tank.

If you do find a leak, repair it right away. Fixing a sewer pipe can be easy or tricky, depending on where the pipe is. Meanwhile, replacing a black tank altogether is a huge job that you probably won’t want to do on your own. Seek a professional for this type of repair.

Got RV Maintenance Issues?

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