How Do RV Toilets Work?

How Do RV Toilets Work?


George Cummings
November 25, 2021

As your portable house on wheels, an RV needs to have all of the creature comforts that you’ve come to rely on at home.

One of the most important is the toilet, with these RV-specific commodes being made to suit their unique surroundings and the requirements of their owners.

How do RV toilets work, though?

RV toilets consist of a toilet seat and controls, just like a regular one, but rather than traveling through pipes and into the sewer system, your waste is stored in a cassette or storage space on board the RV somewhere.

In most cases, this is the black water tank, which must be emptied and cleaned regularly to avoid problems.

An RV toilet must be functioning correctly to keep your RV running smoothly and comfortably, and it’s one of the most important parts of the whole vehicle.

By learning how these toilets work and what’s required to keep them functional, you’ll ensure you never have an issue with your commode out on the road.

How Does an RV Toilet Differ?

How Does an RV Toilet Differ?

One of the most common questions people ask when installing a toilet in their RV is whether a regular toilet like the one they use at home would work.

Although they might seem like the same thing, there are a few major differences that make them incompatible with the motorhome way of life.

  • They’re heavy: RV toilets are lightweight and designed for the bumpy conditions of the road and can deal with a beating. Your home toilet is heavy and usually made of porcelain which would crack in just a short time on the road.
  • They use a lot of water: Your RV toilet is water efficient and uses around ½ gallon every time you flush it. Traditional home toilets use around 1.5 gallons every flush, so you’d run out of water fast if you had one of these in your RV.
  • There’s no sewerage system: The biggest difference between your RV and home toilet is that the toilet doesn’t travel far away but stays right on board the vehicle with you. The sewer system of an RV consists of the toilet and a holding tank full of waste, with the rest being up to you.

How Do RV Toilets Work?

There are a few different types of RV toilets you can use, with pros and cons that need to be weighed up by the individual.

The most common of all is the standard RV toilet that works with a gravity flush and looks and operates just like the commode at home.

The key difference here is that they’re installed over a holding tank and not connected to a septic or sewer system through pipes.

These toilets get their water supply from the holding tank on the RV, and once you’ve done your business and flushed, it’s washed away with water from this tank and down into the main dumping point.

The waste is then held onboard in this black water tank or storage space until you can access a dump station or sewer system where it can be safely discarded.

Types of RV Toilets

Types of RV Toilets

All RV owners have unique needs for how their traveling home should function and that includes the toilet.

To ensure you have the very best commode for your lifestyle, consider each of these toilet setups and what they offer.

  • Macerating toilet: These toilets have a unit at the back with a grinder that mixes up all of the waste as it travels through and turns it into a liquid. They’re gentler on the black tank of the RV and can be emptied even easier, but they’re expensive and have lots of moving parts. The chance of something going wrong is a lot higher and it’s not a risk many people are willing to take when camping in their RV.
  • Composting toilet: Composting toilets don’t require any plumbing to work, but rather collect the liquid and solid waste separately and store them until they can be emptied. The liquid waste is emptied regularly but the solid can be stored longer, and they come in portable and permanent options.
  • Cassette toilet: A cassette toilet uses the gravity flush method as well but also has a detachable holding tank, called a cassette. Most of these toilets have a back door function that lets you remove the cassette for dumping and they can even be emptied in a regular toilet.
  • Portable toilet: As the name suggests, a portable toilet isn’t connected to anything in the RV, but they have a freshwater tank, holding tank, and toilet bowl. You must manually remove the holding tank when it needs to be emptied, but they can be used virtually anywhere, even without your RV.

The Role of the Black Water Tank

The Role of the Black Water Tank

Regardless of the type of RV toilet you use, the black water holding tank is an integral part of the setup.

This large tank varies in size depending on the RV, and its job is to hold all of the waste produced from the toilet, including human excrement.

The toilet is connected to the black tank and an airtight rubber seal sits at the bottom of the RV toilet bowl, keeping any odors and leaks contained so that nothing is noticeable inside of the bathroom.

Ensuring this seal is in good shape is just as important as the toilet itself and it may need replacing occasionally or whenever you notice cracks or damage.

Once the waste passes through to the black tank, it’s stored here until it can be emptied.

Many campgrounds have dumping points that let you connect a hose from the RV to the station and empty it with no mess, otherwise, you can sometimes empty it directly into a sewer or septic system.

The frequency of when it should be emptied differs, with most people doing so every few days while using their RV.

You’ll want to follow guidelines so it creates minimal odors and there’s no chance of waste coming back up from the tank and into the RV, but you also have to be careful not to empty it too frequently or it can dry out the contents and lead to build-ups inside the tank.

Cleaning and Chemical Treatments

Cleaning and Chemical Treatments

Although simpler than your toilet at home, an RV toilet requires even more cleaning and maintenance than its permanent counterpart.

As part of a regular schedule, you’ll need to clean the toilet bowl, apply deodorizer, use a treatment to break down waste in the tank, and clean the tank itself.

Any time you choose cleaning products for the onboard toilet, make sure they’re made specifically for RVs.

This includes whatever chemicals you’re cleaning the bowl with, drop-in packets of treatment for the waste tank, and any deodorizers or other products, as they’re designed for the sensitivities of this type of setup.

A Fuss-Free RV Toilet

The last thing you want going wrong when you’re out on the road in the middle of nowhere is an issue with the RV toilet.

With a little bit of knowledge and a better understanding of what’s required to keep it functional, you’ll ensure that your trusty RV toilet never lets you down.

Related Questions

An RV’s toilet is one of its most convenient functions and without it, you wouldn’t get the full experience of living anywhere you want out of your motorhome.

If you still have questions about these traveling commodes and need to know more, we’ve answered some FAQs that might be able to help.

How Often Should I Empty Black Water Tank?

Dumping the black water holding tank of your RV should be done every three to five days, or when the sensor shows that it’s three-quarters full.

If you notice odors, have been using it a lot, or have more than one person accessing the bathroom, aiming to empty it every three days at a minimum is the best approach.

Do I Need RV Toilet Paper?

Do I Need RV Toilet Paper?

RV-specific toilet paper is a must if you plan on using the toilet in your motorhome otherwise it can lead to blockages and leaks.

Compared to regular toilet tissue, this paper can dissolve and break down easily which makes it gentle on the built-in plumbing system and black water tank onboard your RV.

Can You Empty Black Water Tank At Home?

Most states and local areas allow for black and gray water tanks to be emptied into residential sewer systems but you need to know how to do it safely.

Before attempting to empty the black water tank, check with the local government about ordinances and restrictions in place surrounding this topic.


George Cummings

George Cummings enjoys connecting with nature, meeting new people, and making friends from all over the world. RVing and camping create the perfect opportunity for [him/her] to take part in these activities. After spending several years on the road and exploring the great outdoors, George Cummings shares some of his best pieces of advice on how to make the most of your time while camping. TourTheOutdoors is his way of helping outdoorsy individuals like [him/her] start on a right footing with amazing recommendations and buying guides.