RV Advice

5 Helpful Tips for Your RV Holding Tank

May 18, 2018

Caring for your RV’s holding tank can be one of the less fun chores of owning your own rig. Luckily we’re here to help! RV expert Mark Polk shares five helpful tips for your RV holding tank and it’s maintenance.

I think it’s safe to say we all enjoy the fun and adventure that a new camping season brings, but one of the not so fun chores RV owners are confronted with is waste-water maintenance. You can’t avoid it, so here are five RV holding tank tips to help make the job of waste-water maintenance easier.

Number one on my list is not adding enough water to the black water holding tank after the tank is emptied. Water is your first line of defense against odors and problems from the holding tank. It’s helpful to know what size black water holding tank you have because you want to add enough water to completely cover the bottom of the tank every time you empty the holding tank. One RV holding tank might only need three or four gallons of water to cover the bottom, whereas another one might require five or more gallons. Fill the toilet bowl and add enough water to completely cover the bottom of the holding tank. After you add the water add the correct amount of holding tank treatment to the tank.

Next on my list is the amount of water you add to the holding tank every time you use the toilet. Think about the toilet in your house, even a water saver toilet uses about 1 ½ gallons of water when you flush the toilet. RVs do not have a tank filled with water to assist in flushing the toilet. Remember what I said a moment ago about the water level in the holding tank helping control odors. You need to get in the habit of adding more water to the holding tank every time you flush the toilet. Add plenty of water to the toilet bowl prior to using the toilet too. I can’t stress how important it is to keep the water level above the contents of the holding tank. It not only helps control odors; it helps prevent future problems with your black water holding tank and plumbing.

rv roof vent 360

The third item on my list is controlling RV holding tank odors. RV holding tanks are designed with a vent pipe going from the top of the holding tank to the roof of the RV. One problem is holding tank odors accumulate in the tank and can’t really be vented outside because there is no air pressure in the tank to force the gasses up and out of the vent pipe. The real culprit occurs whenever wind blows across the vent cap on top of the RV roof. The higher air pressure forces air down the vent pipe pushing the tank gasses to the only other way out of the system, the RV toilet. Whenever the air pressure is higher inside the holding tank, than it is inside the RV the odor escapes into the RV by way of the toilet when it is flushed. The good news is there are some effective methods to help control these odors, and it doesn’t involve stronger chemicals. There are aftermarket RV sewer vent caps designed to pull the odors from the tank up and out of the RV, and most of these upgraded vents are easy to install too.

universal sewer adapter

Number four on my list is something RV owners learn through experience; to always keep an assortment of sewer hose adapters and extra lengths of sewer drain hoses in the RV. You never know what type or size of sewer drain connection you might encounter, and you never know how far away the sewer drain will be from the RV. One of my favorite adapters is the Universal 90-degree sewer adapter. It works on most smooth pipe and threaded pipe sewer drain connections you will encounter at campgrounds.

gray water treatment

Last, but as the old saying goes, not least is taking care of the RV’s gray water holding tank too. The gray water holding tank requires some simple maintenance to keep it clean and odor free. After I empty the holding tanks I add some fresh water back into the gray water holding by running water down the sink drains, preferably enough water to cover the bottom of the tank. Next add a gray water tank treatment, or some Dawn dishwashing liquid to the sink drains and run water long enough to get it past the p-traps and into the holding tank. Now when you drive or tow the RV the water and detergent will suds up and move around cleaning the inside of the gray water holding tank.

There are more RV holding tank maintenance requirements than what is listed above, but these five holding tank tips will make your job easier and possibly extend the life of your RV holding tanks.

Happy Camping,

Mark J. Polk

MarkheadshotKOAKOA’s resident RV expert, Mark Polk, and his wife Dawn started RV Education 101 in 1999. Since that time RV Education 101 has helped educate millions of RV owners and RV enthusiasts on how to properly and safely use and maintain their RV. Mark’s favorite past times are RVing in their 35-foot Type A motorhome, and restoring vintage RVs, classic cars and trucks. For more information on how to learn about RVs the easy way, visit RV Education 101. Be sure to check out their RV Online Training Site too!


If you've got an RV, you need these holding tank tips.

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