How Do RV Toilets Work?

The mysteries of the RV toilet are thoughts that sometimes go over looked until it is time to use and clean them. Don't be shy to ask questions!! The travel trailer bathroom, along with the toilet, generally are smaller than that found in most homes. Travel trailer toilets also function a bit differently than a common toilet in your home. Let us go through the types, how to use/clean it, tips/tricks, and what to expect.

The RV Toilet

A typical toilet system in permanent structures like homes, hotels and other brick and mortar buildings works on water pressure. After you flush, it uses water pressure to force the waste through a series of pipes. These pipes either feed into a labyrinth of sewer pipes to a treatment plant or into a septic tank.

Rv toilets primarily use gravity in order to flush. Your toilet may have water that rinses the bowl and fills the bottom of it. The advantage of this system is that it uses less water. Waste goes from the toilet and collects in a separate holding tank (black water tank), it is emptied from outside the travel trailer.

Types of Tanks

Fresh water tanks can hold up to 60+ gallons of water. Typical grey and black water tanks hold up to 30-40 gallons of water and should be emptied every 2-3 days.

  • Fresh Water Tank: The fresh water tank allows you to transport drinking water with you. These tanks vary in size. Besides drinking, this water is used in your toilet to rinse out your bowl. It also feeds your shower and any other built-in device that requires water to operate. When you are parked, you can attach a drinking water safe hose to an adapter on your RV, that avoids the fresh water tank.

  • Grey Water Tank: Your grey water tank stores the dirty water from your sinks and showers. Be careful what goes down into this tank. It is only designed for liquids. The piping to empty this tank is only 1 ½ inch in diameter. If anything thick or solid goes into this tank, it can easily clog.

  • Black Water Tank: The black water tank is just for your toilet. The emptying pipes are 3 inches thick and can handle biological waste and toilet paper. There are specially made toilet papers that must be used for your RV tank. Residential toilet paper will not fully break up and can clog your system.

Usage and Emptying

To prepare the toilet you need to be sure to have the proper water source. This can be either be through your RV’s freshwater tank or through a campsite water hook-up. The bowl itself needs to be at-least half way filled with water.

There should be a pedal at the bottom of your toilet that you can press with your foot. Hold this down until the bowl is about halfway full. This is the same way you flush the toilet! Once you take care of your business, just press the pedal down and wait until the bowl is empty before releasing the pedal.

Most campgrounds have sanitation stations, or dump stations. Both the gray and black water tanks have valves located under the trailer and a connection point for a hose to reach from the trailer to the opening in the dump station. Sewer Hoses usually are 3 to 4 inches wide and 10 to 20 feet long. Once the hose is in place, the valve for the black tank is open and the waste flows down into the dump station. The gray tank valve is opened and that tank drains. Emptying the gray tank last helps to flush remaining matter out of the hose. It is best to wear gloves while dumping the tanks.


Yes, you do need special toilet paper for your RV Toilet. RV toilet paper, unlike the kind used at home, is easily dissolvable RV toilet paper helps ensure your RV toilet works as it should throughout your trip, especially when it is time to dump the waste.

The only thing you should be flushing is RV Toilet Paper. Do not flush facial tissues, wipes feminine napkins or tampons in your RV toilet. These items can cause your RV toilet and tank drain to clog. You shouldn’t dispose of food in your RV toilet, such as grease or oil, as this can cause damage to your RV rental.

If your RV toilet does end up clogged, do not use corrosive chemicals! This can also damage your RV toilet’s mechanism. Use an RV-specific holding tank treatment to break down solid materials, liquefy waste, and control the odor. A safer way to deal with backup in your RV toilet if it occurs is to fill the bowl with hot water and let it sit in the bowl. After a little while, the water should help your blockage dissolve.

After emptying your black tank run fresh water in the toilet, this helps flush out any remaining waste. After valves have been shut off and hoses disconnected flush the toilet to allow black tank to fill up, at this point you can add powder or liquid waste treatment to further break down wastes.

Chemical treatments that you can use are blue chemicals and biological treatment to break down odors and wastes.


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