My RV Toilet Smells When I Flush

September 10, 2019

My RV Toilet Smells When I Flush Image of RV Toilet Bowl With Gross Smells Coming From The Bowl

Key Points

  • Your toilet smells because “bad” anaerobic bacteria from your stomach are breaking down the urine, toilet paper, and feces in the tank and in that process they are releasing hydrogen sulfide gas, that all-too-familiar sewer smell.
  • To eliminate this toilet odor you need to stop the “bad” anaerobic bacteria from creating the hydrogen sulfide gas.
  • You don’t want to kill the bacteria inside your holding tank because without them, solid waste will collect and clog your tanks and cause your sensors to read improperly. Instead, you want to replace the “bad” bacteria with “good” aerobic bacteria.
  • To do this effectively you need to use a high-quality bacteria-based treatment. Not all treatments are created equal, so do your research and choose the best. We recommend Unique RV Digest-It.
  • Besides using the right bacteria treatment, you need to follow the proper tank-maintenance procedures. We recommend The Unique Method.

Nothing ruins a camping trip in your RV more than nasty smells coming from your RV’s toilet! Whether your RV toilet smells when you hold down the flush peddle or you smell it constantly throughout your RV, awful odors in your RV can be frustrating, disgusting, embarrassing and even dangerous. Luckily, there is an easy solution to controlling RV toilet odor.

But first, what causes RV toilet odor? The nasty odors emanating from your holding tank are a result of “bad” anaerobic bacteria (from your stomach) breaking down the urine and solid waste — toilet paper and poop — inside your holding tank and releasing hydrogen sulfide gas (that horrible rotten egg smell). If these “bad” anaerobic bacteria aren’t controlled in your holding tank, you will perpetually be stuck dealing with awful odors.

Inside your stomach, anaerobic bacteria are essential in the process of breaking down food, acting as a crucial component of digestion. There main objective is to break down solid food so that you can excrete the waste. They thrive inside your digestive tract because they don’t require oxygen to survive — but this lack of oxygen is problematic because it causes these types of bacteria to be unable to release oxygen as they breakdown the waste. They, instead, breakdown the waste and release hydrogen sulfide gas in the process. When you pass gas or burp it’s normally from the over-production of gas from these anaerobic bacteria doing their jobs. They need to break down the waste and the natural gas they release has to go somewhere.

When you use your RV’s bathroom, these anaerobic bacteria enter your holding tank and continue to break down solid waste. As mentioned above, this process emits hydrogen sulfide gas. When you flush your RV’s toilet, the valve slides open and momentarily allows all those foul-smelling gasses to seep into your RV.

Now that you understand exactly why bad RV toilet smells occur, what are the solutions?

The best way to control RV toilet smells is to eliminate “bad” anaerobic bacteria. There are three basic options for doing this:

  1. Kill the anaerobic bacteria with caustic chemicals or formaldehyde
  2. Cover the smells with strong fragrances
  3. Replace “bad” anaerobic bacteria with “good” aerobic bacteria.

Killing The Anaerobic Bacteria

Let us be clear about this: You never want to just kill the bacteria inside your holding tank with caustic chemicals or formaldehyde-based products. The bacteria present in your tank are extremely crucial in the process of waste breakdown and killing them will lead to an accumulation of solid waste in your black water tank and you will almost certainly get pyramid plugs, clogs and odors in your toilet. And if you think the odors coming from your toilet are bad — you should see how bad a tank clog is!

Besides being problematic inside the holding tank, we also recommend that you avoid formaldehyde products because they are simply not safe for people or the environment. This alone should give you pause the next time it’s recommended that you use an "old-school" chemical cleaner or formaldehyde product.

Covering The Toilet Smells With Fragrances

A close cousin to the old-school formaldehyde treatments are those that contain overpowering fragrances. With these products you’re simply covering one bad smell with another. If a product comes with an overpowering fragrance, you can automatically assume that product isn’t very good at truly eliminating odors or breaking down the waste at their core.

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Replacing The Bad Bacteria With Good Bacteria

The best way to solve toilet odors without exposing yourself to clogs and solid waste back-up is to replace the “bad” anaerobic bacteria with “good” aerobic bacteria.

If you are like most RV owners who don’t want caustic chemicals inside the small living space of their RV, then the third option (and honestly, the correct option!) is replacing the “bad” anaerobic bacteria with “good” aerobic bacteria. This is easy to do! Start by treating your holding tanks with a high-quality bacteria-enzyme treatment. We recommend RV Digest-It as it is the best RV holding tank treatment available today and comes in Liquid, Scoopable Powder and Drop-In Pod formulations. RV Digest-It contains billions of “good” aerobic bacteria in every treatment and instead of emitting smelly hydrogen sulfide gasses, aerobic bacteria release only carbon dioxide and water when breaking down waste, leaving your holding tank odor FREE.

It’s important to know that not all bacteria treatments are created equal, so make sure you’re not throwing money down the drain by buying over-priced, underwhelming treatments. Most bacteria / enzyme treatments available today have old technology and watered-down formulations that will not solve your odor or waste problems. Learn more about selecting the right treatment here.

Now that you know killing the bacteria with chemicals and filling your holding tank with overpowering fragrances isn't the most effective way to rid yourself of RV toilet odors, it's important to understand even if are using the best treatments like RV Digest-It, without implementing correct black water care habits you may still experience problems.

Think of it this way: It won’t matter if you buy the best toothpaste and toothbrushes if you are scrubbing your ears with them! To make them effective you have to use them correctly! This is where proper black water care habits come in. To make sure you’re treating your holding tanks correctly, we recommend following The Unique Method. You can learn more about The Unique Method here.

Basic implementation of the of The Unique Method includes the following steps:

  1. Always keep your black tank valve closed, unless you’re dumping your tank.
  2. Always treat your holding tanks with a high-quality bacteria + enzyme treatment each time you dump. We suggest Unique RV Digest-It.
  3. Always fill your toilet bowl with water BEFORE you use the toilet. This will help waste to flow effectively down the line.
  4. Use ample amounts of water each time you flush your toilet. Water is a HUGE component to proper tank maintenance. We recommend holding down your flush pedal for ten full seconds each time your flush your toilet. This will hydrate the good bacteria inside the tank and allow them to adequately break down solid waste. It will also ensure that all of the solid waste inside your tank is covered by water, which will help suppress odors.
  5. Always keep several inches of water in your toilet bowl. This will prevent foul smells from seeping into your RV.
  6. Keep your tank temperatures below 85 degrees. If you believe the tank is exceeding 85 degrees, use more water with each flush and consider increasing the treatment dose.
  7. Ideally, you should dump your tanks every 3-5 days for optimum odor control. If you are going to extend the time between dumps, treat your tanks every 4 days with your bacteria + enzyme treatment and keep plenty of water in your holding tank. Doing so will boost the microbial count inside your tank and allow the bacteria to work in this nonoptimal environment.
  8. Flush your holding tank for 20-30 minutes every 3-5 dumps with a built-in tank-rinser, external tank-flusher, or wand. This is crucial, because waste (no matter how well it gets digested by your tank treatment) will collect and accumulate in the low spots of your holding tank if your RV isn’t parked 100% level (and most RVs are always parked ever so slightly out of level). Waste cannot gravity-drain when you dump your tanks, so it must be manually flushed out.
  9. Never clean your toilets with chemicals or bleach. Use only RV toilet cleaners, like Unique RV Toilet Cleaner. Using chemicals or bleach will kill the active bacteria that are doing their part to keep your hold tank systems working properly.
  10. Perform a deep clean on your black tank twice per year. Unique Tank Cleaner is specially designed for biannual tank treatments. This will flush out the system, remove waste from the sidewalls and tank floor, remove debris that may have collected on the sensor probes, and lubricate your valves and seals.

We cannot overstate how important it is to use plenty of water in your holding tank. This hydrates the aerobic bacteria, helping to break down waste. Also, using plenty of water in your holding tank creates a barrier over the waste. This can drastically help to control those bad RV toilet odors. Don’t think it’s important to cover waste with water? Just step inside a porta-potty with a large mound of poop, and the unbearable stench will quickly show you how crucial it is to cover waste with water! It is also recommended that you fill your toilet bowl with a few inches of water (just like your toilet at home), creating yet another barrier between you and those disgusting smells.

Why does my RV toilet smell in hot temperatures? And what can I do to remedy this?

Great question. It is true that in hot temperatures, RV toilet smells can become even worse. This is because in high heat the “bad” anaerobic bacteria are allowed to flourish instead of the “good” aerobic bacteria. If you are experiencing odors in hot weather you simply need to use more water in your holding tank to help the “good” aerobic bacteria from RV Digest-It to thrive. It is also helpful to add more RV Digest-It to increase the “good” bacteria in the tank.

Again, this is where following good holding tank habits, like those found in The Unique Method, are crucial.

To increase the amount of water inside your holding tanks, simply hold down your toilet flush peddle longer with each flush.

It can also be helpful to dump your holding tank more often (every 4-5 days in hot weather).

Finally, in excessive heat, you may want include a mineral/salt product like Unique Tank Odor Eliminator into your normal treatment regimen. This product is designed to eliminate tank odors in high heat situations, but it will not break down waste, so it should be used in conjunction with RV Digest-It, not in place of it.

Now that you have the tools to prevent disgusting RV toilet smells from ruining your adventures in the great outdoors, please feel free to peruse our additional articles. If you need more assistance, or have any further questions, please feel free to reach out! We’re here to help:

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