One of the worst issues faced by RVers is holding tank odor you just can’t seem to get rid of.

Because we travel with toilets in tow, we must sometimes carry our wastewater with us in our camper’s internal holding tanks.

And when that kind of water gets to stinking, those smells can creep into your RV — resulting in an unpleasant experience for you and your fellow travel companions.

So, how do you get rid of holding tank odor?

I’ve been a full-timer for 4+ years now, so I can confidently tell you that you get rid of holding tank odor by emptying and cleaning your tanks, unclogging your tank vents, and inspecting your RV toilet for bad seals.

You can then prevent black tank smell in your camper by using septic-safe RV toilet paper, leaving your dump valves closed until your tank has water in it, regularly cleaning your tanks, and periodically putting a holding tank treatment down your toilet.

In this article, I’ll unpack all the steps I’ve learned to get rid of holding tank odor and to stop it from coming back.

Causes Of Holding Tank Odor

Causes Of Holding Tank Odor In Your Camper

RV holding tanks are divided into two types — black and grey.

Black tanks handle the sewage from your RV whereas the grey tank handles the drain water from your shower and sinks.

While your grey tank can sometimes have an odor (especially if you dump lots of food particles down your sink) your black tank is almost always the cause of the worst holding tank odors.

Here’s what usually causes your black holding tank to send a nasty odor into your camper:

    The tank is full — I know it sounds like a no-brainer, but life on the road can sometimes get so hectic that you lose track of just how full your holding tank is getting. And when your holding tank is full, strange smells can emanate into your RV.
    A blocked tank vent — RV holding tanks have vents which are actually just pipes sticking out of the tank and (usually) out your roof to allow smells to escape. If leaves, pinecones, or any other outdoor invader is blocking that vent, then holding tank odor has nowhere to escape except inside your camper.
    Leaky toilet seals – Sometimes the odor isn’t coming from your holding tank and fluids are simply leaking from your RV toilet itself.
    Holding tank buildup – If you haven’t cleaned your holding tank in awhile (or ever), nasty buildup in there could be the cause of your holding tank odor.
    Using the wrong kind of toilet paper – If you use anything other than septic safe toilet paper, your TP won’t dissolve properly and it’ll create a turd-block in your tank. This block will prevent a bunch of nastiness from draining out and that nastiness will start to smell — causing holding tank odor.
    Changes in temperature or environment — Sometimes the cause of holding tank odor is as simple as a change in temperature. Especially when it gets hot outside, you might notice some new holding tank odors.
How To Get Rid Of Holding Tank Odor


How To Get Rid Of Holding Tank Odor 

When it comes to getting rid of holding tank odor, your first step is to understand exactly where the odor is coming from so you can then eliminate it. 

1. Start by ensuring your tank is empty

Try emptying your tank first and then throwing in some tank treatment with some fresh water. Give it a few days and if you still have holding tank odor, then check out the next few questions.

2. Is your holding tank vent blocked?

Holding tanks have a vent that is basically a PVC pipe going up and (usually) out your RV roof.

Check your RV owners manual for the vent’s exact location. Once you find it, you can make sure the vent is clear by simply putting a water hose in it and running water down it. 

Just be sure you have your holding tank open when you do this so the water and debris can drain out.

And don’t worry – because the vent is up and out from your tank, it shouldn’t have any nastiness in it. These vents usually get blocked by outdoor debris leaves.

3. Do you suspect an RV toilet leak?

As RV toilet seals get older, they can start to leak. If this is the case for you, no amount of holding tank cleaning or vent unclogging will help.

Unless you confirm that water is leaking out your RV toilet’s floor flange, I’d recommend chatting with an RV professional because it can be really difficult to isolate and repair internal toilet seals.

Alternatively, if your RV toilet is old and you’ve tried everything else to eliminate holding tank odor with little success, it might be time for a new RV toilet.

New RV toilets are generally affordable and easy to install yourself.

How To Clean Your Holding Tanks To Get Rid Of Odor

If you don’t suspect a clogged holding tank vent or leaky toilet seal as the culprit, chances are good that your holding tank is stinking because it hasn’t been cleaned in awhile.

Regular cleaning of holding tanks and tank vents is one of the surest ways to eliminate and prevent holding tank odor.

Here’s how to clean your holding tanks (note: this method works for both your black and grey tanks):

    Attach an RV sewer hose with a clear elbow: In order to properly clean your holding tanks and get rid of odor, you need to be able to see when the water draining out is clean. Sewer hoses with clear elbows will allow you to see the water as it’s draining out of your holding tanks.
    Empty tanks entirely, making sure to clear any clogs: If you’ve accidentally used toilet paper that isn’t septic safe or haven’t been flushing with enough water, you could create a clog in your tank that prevents water from getting out. This will cause odors to build up as nasty liquid hangs out in your tank. If you suspect you’ve got a clog, you should first try filling your holding tank with freshwater and then dumping it.
    If emptying tanks doesn’t clear the clog: you should try a DIY kit like this one to fully flush your holding tanks.
    Rinse and repeat: Once your holding tank is empty, fill it back up with freshwater and dump. Repeat this process until you see clean water flowing through the sewer hose elbow.Pro tip: By running a hose into your camper or attaching a hose to your bathroom sink, you can put fresh water into your holding tanks more quickly by shooting it down your toilet.
    Add ¼ tank of freshwater back into your holding tank with tank cleaner: Add some water back into your holding tank along with a tank cleaner like this one.
    Take a short drive so the tank water can slosh around : This will help mix the tank cleaner and the water.
    Empty the tank one more time : The tank cleaner will loosen up any remaining odor causing debris that’s hanging onto your holding tank.By dumping your holding tank after adding cleaning chemicals, you’ll send the smelly stuff packing.
How To Prevent Holding Tank Odor


How To Prevent Holding Tank Odor

Now that your holding tank is clean, tank vents are cleared, and/or your toilet seals are in good shape, it’s time to get rid of holding tank odor by preventing it from coming back.

Here are 7 must-do tasks to stop holding tank odor:

  • Use generous amounts of water when you flush — By adding extra water to your holding tanks, you’ll create an environment where solids can break down and easily slide down the chute when you dump your holding tanks.
  • Leave your dump valve closed until you need to dump — If you’re at an RV park and always leave the valve to your black tank open, then water won’t hang out long enough to dissolve solids. You can prevent this issue by letting your holding tanks fill up and periodically dumping them.
  • Always use septic safe toilet paper — Septic safe toilet paper is not hard to find, so there’s no excuse for not using it. You don’t even have to go to the RV store to get it — virtually anywhere you get toilet paper has the septic safe variety and it’ll be clearly labeled as such on the packaging.
  • Always use septic safe toilet paper — Septic safe toilet paper is not hard to find, so there’s no excuse for not using it. You don’t even have to go to the RV store to get it — virtually anywhere you get toilet paper has the septic safe variety and it’ll be clearly labeled as such on the packaging.
  • Clean your holding tank vents quarterly — Because you never know what can get into those vents and clog them up, you should do a quick proactive cleaning every quarter.
  • Rinse out your holding tank every time you dump — Every time you dump your tanks from now on, add extra fresh water in them until your sewer hose starts draining clear.
  • Periodically add in tank treatment — Tank treatment like this will help you get rid of holding tank odor for good if you regularly use it. 
  • Clean the toilet and flapper —  You should regularly clean your RV toilet and flapper (the thing that flaps down to send poo down your toilet) using a household toilet brush. Keeping your toilet clean will help keep odors down that might seem to be coming from your holding tank.

I’ve come a long way on my journey as a full-time RVer. I’ve learned how to dump my holding tanks, how to get rid of holding tank odor, and how to keep holding tank odor away.

If you follow the lead I’ve laid out for you above, you too can set yourself up for many miles of odor free adventuring.