sewer hose from RV black water tank to sewer

Sick of a Smelly, Dirty RV Black Water Tank? Follow These Simple Tips

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Nothing ruins a camping trip faster than a foul odor stinking up your entire rig. Thankfully, there are some simple tips and tricks you can use to keep your RV black water tank working (and smelling) better. 

What is the RV Black Water Tank?

In case you’re a total newbie, here’s a rundown of what the black water tank is. This tank is essentially your RV’s sewer system. In a house, you are connected to a septic tank or to the city sewage system. The RV black water tank works kind of like a mini septic tank. It stores everything you flush down the toilet until you dump your tanks at a dump station or a full hookup site.

Why You Should Never Leave Your RV Black Water Tank Valve Open

Some RVs make a major mistake when operating the RV black water tank. Leaving the tank open all the time. This is a huge no-no. Your sewer hose will reek something awful. But even worse, you could actually end up with a clogged toilet. 

When you leave the black tank valve open, the liquid will flow out of the tank but most or all of the solid waste will stay in the tank. Any solid waste that does get out will end up sitting in your sewer hose. Joel and I were once parked next to someone who did this, and the smell was so awful we couldn’t even go outside. 

When solid waste and toilet paper stay behind in your tank you can get what RVers refer to as the poo pyramid or pyramid plug. It is literally a pyramid of your waste that eventually accumulates to where it clogs your toilet. Talk about disgusting. 

The easiest way to prevent this nasty problem is to simply keep your black tank valve closed until it is time to dump your tanks. You should also make sure to use enough water when you flush. If you’re already in a predicament, this article on unclogging an RV toilet has some great tips. 

If you use toilet paper that doesn’t break down in your tank, you also increase your risk of having a clogged toilet. You don’t actually need RV toilet paper, but you do need something that breaks down. 

RV black water tank valves

The Correct Way to Dump Your RV Tanks 

So if you aren’t supposed to leave your RV black water tank valve open, how do you dump your tanks? It’s really quite simple. When the time comes to dump your tank, first open the black water tank. Keep the valve open until the flow stops.

After that, you dump your grey water tank. You should always dump your black tank and then your grey. Dumping the grey water second ensures any solid waste or toilet paper left behind in the hose gets flushed out. Otherwise, your hose can get really smelly really fast. 

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Many RVs have sensors that tell you when the black and grey water tanks are full. Unfortunately, these aren’t often accurate. Toilet paper stuck on a sensor is enough to make it seem like your tank is full even if you only recently dumped it. 

Cleaning your black water tank with a swivel stik can help clean the sensors and keep your tank in tip-top shape. Once you have been RVing for a while, you’ll also start to gauge how long your family can go before needing to dump the tank. If your tank starts to smell a little funky, it could be a sign that you’re due to empty them. 

The more people you have in your rig, the more often you’ll need to dump your tanks. 

How to Keep Your Black Water Tank From Smelling So Horrible 

I don’t know if I have met a single RVer who hasn’t encountered a smelly black water tank at one point. It happens to all of us. Luckily, once you learn the tricks, there are ways to cut down on the smell and make your camping experience much more pleasant. 

Use a Sanitizing Product 

One of the best ways to keep your RV black water tank smelling fresh and clean is to use a sanitizing product. Happy Camper is a popular product among many RVers. It is convenient because you can use it in your black and grey tanks to keep the smell under control. It is also easy to use. Just add a scoop, flush, rinse, and you’re good to go. 

There are also many other black tank treatment products out there. Some are better than others, but in most cases, something is better than nothing! 

Check Your Toilet Seals and Keep Some Water in the Bowl

Another easy way to stop the smell is to add a bit of water to the toilet bowl. This helps stop the smell from seeping out into your RV. If your toilet doesn’t have a good seal in the bowl, all the water will drip into the tank and the smells from your tank will get out. 

Ensure Your Vent is Properly Functioning

You may also need to unblock or replace your tank vent. This vent is on the roof of your RV and vents the air from your tanks out of your RV. If it is blocked or otherwise malfunctioning, the air from your tank gets vented inside the RV. 

This happened to Joel and I once. Honestly, we were practically sick by the time we reached our destination the odor was so bad (despite our tanks being empty). Joel replaced the vent and presto, no more reeking RV! 

Have you had a smelly black water tank before? What did you do to fix the problem?


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Kathryn Mancewicz

Kathryn Mancewicz is an RV expert who has been a full time RVer since 2019. She has bylines for her RV related content on major publications including MSN, MSN Canada, and AOL. She has also been featured on Yahoo and quoted on KOA. Kathryn is also a regular RV content writer for Cheapism.