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How Does an RV Toilet Work? Explore Answer Right Away!

Written by Philip Lopez / Fact checked by Paul Lemaire

how does an rv toilet work

RV toilets are one of the essential comforts in RVing because they’re where you do your business when nature calls. These rooms look pretty much the same as residential lavatories, but how does an RV toilet work? You need to know how it functions to repair and maintain it.

Generally, an RV toilet comes in different types, but all have basic parts like the bowl and the holding tank. A foot pedal may exist to activate the flushing system. Unlike residential toilets, you need to empty the black tank regularly when it fills up.

Let’s learn how toilets work in RVs, their components, and more below.

Table of Contents

RV Toilet

Usually, you’ll find a foot pedal at the base and a black tank that connects to the toilet drain. Once you’ve answered nature’s call, step on the foot pedal for a few seconds to flush the waste down into the pipes leading to your black water holding tank.

The black tank carries all the waste, and it gets filled up over time. Once it does, empty it in a proper RV dump site using a flexible hose.

Some Dometic toilet work with a hand flush, which accomplishes the same thing as the pedal. It fills the bowl with water and flushes the waste down. The benefit of this design is that you can flush the toilet while sitting.

Water Tank


Camper toilets work with a fresh water tank and black water tank to function properly. If you have a shower or sink, then your RV probably has a gray water tank. These tanks are located at the camper’s underside when looking at the RV toilet system diagram.

  • Fresh water tank

The RV’s water supply is sourced from the fresh water tank when off the grid. It is where you get your water for flushing the toilet, showering, and other water needs. As long as you sanitize the tank, you can also use its water for drinking and cooking.

  • Black water tank

All of the waste from your toilet goes to the black water tank. This includes toilet paper, urine, and fecal matter. The tank allows you to use a camper toilet while you’re boondocking far away from a sewer connection.

The capacity may vary, but it’s always wise to choose a larger tank when traveling to have a longer time using the RV toilet. A 50-gallon black water tank is enough to last for 10-11 days for two people.

  • Gray water tank

Another waste tank in your RV is intended for gray water, which may come from the indoor showers and sinks. When you take a shower or wash clothes, the wastewater goes into the gray tank. Not all RVs have this type of tank, but it’s a convenient addition to avoid filling the black water tank quickly.

The size of the gray water tank depends on the vehicle type. Generally, it ranges from 25-95 gallons.

Sewer Hoses

RV bathrooms work with sewer hoses to dump the black and gray water tanks at designated drainage points. These hoses are usually long and flexible to reach tight corners. They’re a critical part of the RV toilet system because any mishap means spillage that can ruin your vacation.

To avoid any dreadful spill, look for good fittings and adapters that provide a secure seal. Also, think about your RV’s storage capacity when deciding the sewer hose’s length. Choose a 20-foot hose if you have room and settle for a shorter hose if you have a limited storage capacity.

Also, find the right sewer hose support for your RV here!

Toilet Chemicals

Commodes for campers rely on toilet chemicals to keep things clean and stink-free. You add these chemicals after you empty the black tank. They break down the waste to prevent blockages, thanks to components like formaldehyde and bleach.

You can find toilet chemicals in two forms:

  • Liquid: This form of toilet chemicals are effective in breaking down waste and toilet paper. The concentrated formula might be a little difficult to use because it needs a certain amount of water to work, so follow the label’s instructions.
  • Dissolving Pack/Tablet: A more convenient option is to use pre-portioned dissolving packs. The best part of this form is that you can flush it in the black tank without any measurements.

Types of RV Toilets

Indeed, you cannot use a regular toilet in RV, as only models designed for the vehicle can meet its requirements.

RV toilets come in many varieties, although they serve the same purpose of dealing with human waste. Here are five basic types of RV toilets and how each works.

  • Gravity Flush RV Toilet


This is the most common type of RV toilet with foot pedals to activate the flushing system. Water fills the bowl every time you hit the pedal and flush the waste down into the black tank. When the tank gets full, empty it at the designated dump site.

  • Macerating RV Toilet


To prevent clogging problems, you can use a macerating RV toilet. This type comes with motorized blades to grind the solid waste into fine particles. The pump directs the waste into the holding tank, so the lavatory doesn’t necessarily need to be above the black tank.

The versatility makes it a nice addition as a second toilet in the RV.

  • Composting RV Toilet


A composting toilet makes a nice option if you dislike plumbing work in an RV. It doesn’t need any large holding tanks and water to work. Instead, it uses a composting material like peat moss to turn the solid waste into compost, making it perfect for boondocking.

Most of these toilets come with a fan to help move the bad-smelling air outside the bowl. This sounds pretty convenient if you’re alone in the camper, but not for large groups because it means dumping constantly.

  • Cassette RV Toilet


This type of motorhome toilet is pretty simple, making it a nice option for small RV bathrooms. The cassette toilet itself is fixed in the RV, but the black tank is removable from the outside. Many RVers love this design because they can easily empty the tank at the nearest dump station or toilet.

Some models even come with wheels and telescopic handles to facilitate waste transfer.

Note that you may find portable cassette models as well, which have their own water tanks for flushing.

Related post: The difference between cassette toilet and black tank

  • Portable RV Toilet


Lightweight and simple, these portable toilets are easy to carry around anywhere. They look like buckets, so they’re very affordable. Some models come with a small holding tank for all the waste while others use a plastic bag and organic materials inside the bucket.

How to Maintain RV Toilets


RV toilet maintenance is more than just cleaning. It involves careful inspection of parts to prevent leaks and odors.

  • Use RV toilet properly: Add ample amount of water in the bowl to aid the thorough flushing of solid wastes. Make sure to hit the foot pedal or hand lever for several seconds to flush the waste completely.

If you’re using RV toilet for the first time, add a good chemical and plenty of water (typically 4 quarts) to the black tank to keep the bad odor at bay.

  • Check the toilet seal: Water leaks and bad odor can escape from the bathroom if the toilet seal is broken. Make sure that you check the seal before and after the RV trip. Consider replacing the seal when it has lost its elasticity.
  • Clean with the right materials: The RV toilet valve is made of plastic, so it can easily get damaged by caustic chemical substances. Look for cleaning solutions that are made specifically for RVs and a non-abrasive bowl brush.

Frequently Asked Questions


How often do RV toilets need to be emptied?

It depends on the size of the black tank and the number of people using the toilet. On average, you can empty an RV toilet every three days.

Should you keep water in RV toilet?

Yes, you should have water in the toilet before doing your business. Doing so makes flushing easier as nothing will stick to the bowl, keeping it clean and odor-free.

How much water does an RV toilet use per flush?

Most RV toilets use three liters of water for flushing. This amount of water can help neutralize the odor and ensure that every nasty bit is flushed into the tank.


At this point, you know the answer to the question “how does an RV toilet work?” It’s pretty similar to your home fixture, except for a few differences in the plumbing system. To keep the RV toilet in good condition, flush and empty the black tank properly.

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