How does an RV Toilet actually Work?

Science, Witchcraft, or Both?

Relax...it's science, but that doesn't make it any less scary. The inner working of your RV can be intimidating, and very few things carry as many "no I don't really want to mess with that" vibes as your toilet. It's something that is often taken for granted in our homes, so when it's something in our RV, we want to know as much as we can about it (we can't exactly call a plumber when we're boondocking in the middle of nowhere), but we don't have much of a basis to start from. That's where we come in, to give you an all-encompassing guide to how your RV toilet functions.

I solemnly swear to make as few toilet-related puns as possible (some cannot be avoided). So let's take a deep breath, try our best to be mature, and have a talk about toilets.

An Overview of Your RV Water System

When discussing your RV toilet, it helps to first understand where it fits into your overall water system. Because the toilet is on the same system as your sink and your shower (I know this sounds gross, but it's the same way at your house and it works just fine I promise).

Water can either come in through a city water inlet (if your campground has one) or from your fresh water tank. It flows through your pipes until it splits, with some of it flowing to your hot water heater and some of it going directly to your appliances. This explains why your sink can dispense hot or cold water. The used sink or shower water then flows into your gray water tank, where it's journey comes to an end. The water destined for less dignified functions is fed via gravity (that part is important) to your toilet, and once its *ahem* served its purpose, it is flushed to the black water tank which is the #2 tank in this example, both literally and figuratively. The black water tank must be placed directly below your toilet (because you know, that's how gravity works).

The black water tank can be emptied at a designated RV disposal station, with a hose that is attached to the tank itself. Learn more about that process by clicking here.

Side Note: There are other types of RV toilets that do not operate this way. I will mention those shortly, but this explaination applies to the vast majority of RV toilet systems. And all other types will be a deviation of this system, so it helps to understand the basics.

Gravity: Is That All it Takes to Operate an RV Toilet?

At the risk of being anti-climatic, it really is that simple. There is a stopper in the bottom of the toilet bowl, and when you press down on the foot pedal to flush it (RV toilets generally have a foot pedal rather than the typical flushing mechanism), the used waste water flows in the direction of gravity to the black tank, The water above the toilet in the pipes flows into the toilet replacing the recently flushed water, using the pressure created by gravity itself. There is no secret engineering magic involved here, just basic laws of physics. So next time you do your business in your RV, make sure to give a nod to Isaac Newton and his apple for making this all possible. As a brief disclaimer, I'm not actually sure if the story of the apple is real, but you're not really going to think of Isaac Newton anyway so let's just move on.

What is more interesting, are the various types of toilets that exist in the RV world. They've come up with some pretty creative solutions to a real stink of a problem...I know it's another toilet joke, I hadn't hit my quota for this section.

So Let's Get to the Good Part. What Kinds of RV Toilets are There?

We've already gone over the traditional RV toilet, but there are plenty of others. There are portable toilets, composting toilets, cassette toilets, incinerator toilets (yes you read that right), and macerating toilets. They all differ in various ways, and serve distinct purposes. Let's look over what makes them unique.

Portable RV Toilet

A portable toilet doesn't utilize a black tank, or plug into the main water system at all. It is most commonly used in small campers without an interior water system. It can even be used outside if you're into that sort of thing.

The biggest advantage is apparent, portability. You can have a toilet where you otherwise couldn't, and 4 out of 5 dentists recommend you use this instead of a tree in the middle of the night when you don't want to put shoes on. However, the drawbacks make it a tough sell for those who don't absolutely require the advantage of portability. It has to be emptied manually, which is just as bad as it sounds. Fortunately they do sell deodorant for portable RV toilet systems, so at least that problem is taken care of.

If your camper is too small for a toilet, or you find yourself boondocking in the middle of nowhere with little to no access to facilities, this could be a great toilet for you in a pinch.

This toilet goes where you need it to, so you can go where you need to

Composting Toilet

If you were bored by the scientific simplicity of standard, gravity fed toilets, I have the perfect style for you. A composting toilet uses natural processes to turn your lunch into an environmentally friendly compost.

This style is generally found in large motorhomes, and has a few key differences from standard toilets, the first being that waste is separated into solid and liquid waste. Liquid waste goes into a removeable tank, but solid waste gets filtered into a different tank, where it is broken down into an odorless compost that can be dumped into a dumpster or non-edible garden. This process can take hours or days depending on your toilet. There is also a large handle that disturbs the composting material and the soon-to-be compost, which assists in the process.

This is a great option if you will be camping for long periods of time in places where you may not have a waste disposal site, and is by and large a good self-sustaining option for waste overall, because these toilets also require no water to operate. Not to mention you can directly contribute to the plants and trees at your favorite campsites! Is that a plus? I think thats a plus.

The circle of life is working in full force here

Cassette Toilet

A cassette toilet is very similar to a traditional RV toilet, with a few key differences.

The most notable is that instead of draining with a hose leading off your black water tank, the black water tank itself is completely removable. This offers a bit more flexibility in design for smaller campers that don't have the room for full plumbing systems but still want a toilet.

Now you do not have to park your RV at a dump site in order to drain it. You can simply remove the black tank, and carry it to either a dump site, or if your campground has restrooms, it can be emptied there as well. So if the nearest bathroom is a quarter of a mile away, or you just want a private place to do your business, this will work for you. All in all this is a great system to have if you want flexibility and are camping places that might not have a dump site nearby.

You'll be a hit at your campground walking around with your black water tank.

Incinerator Toilet

If you're like me (and I know I am) the first thing you thought when reading this question was "Maybe we can use lasers?" While this isn't technically what's going on here, this is just about as close as you can get to vaporizing the mess away, sci-fi style.

An incinerator toilet can either use electricity or propane/gas to operate, and requires no water. Once the tank is full, you simply turn the incinerator on, and the tank heats up to roughly 1400 degrees Fahrenheit. This process takes about 30 minutes for electric toilets, and 3-4 hours for propane or gas toilets. Some toilets say that they're safe to use during the incineration cycle, but that sounds terrifying to me personally, so please consult your manual if you plan on doing so. The incinerator toilet hooks up to a vent to funnel unwanted fumes outside of your camper, and uses roughly 1.5 kWh per incinerating cycle, which sounds like a lot but you can use it roughly 40-60 times (depending on your diet) before an incineration cycle is required.

Once it is all finished, Viola! you are left with a small pile of ash! You can dispose of this wherever you would dispose of household garbage.

I would call this toilet the flamethrower. You guys name your toilets right?

Macerating RV Toilet

If you prefer a more visceral and less science-y approach to your waste disposal, then the macerating toilet is right up your alley.

This toilet offers a lot of the comforts of home, it can handle solid or liquid waste equally well, and even can handle standard household toilet paper easily (many RV toilet systems require a specific toilet paper to function optimally). It has a pump that moves waste to your black water tank, so it can be installed anywhere in your RV, and doesn't require gravity to move waste through your system. The pump allows freedom in the design of the camper. Want your toilet on the opposite side of the black water tank? Macerating toilets have got your back.

How does it do all of these great things you ask? Well, it has a system of grinding blades to slice, dice, and liquify everything that passes through the system. It operates very similarly to a garbage disposal at your home. This allows waste to move through the system more consistently, and can be emptied with a much smaller hose than the typical 3-inch hoses seen on traditional systems.

If the idea of turning your black water tank into a glorified smoothie maker doesn't make your stomach turn, then the conveniences of a macerating toilet would offer you a flexibility that almost makes it feel like you're back at home (with the minor exception of the toilet swords of course).

This toilet doesn't look like much, but it will definitely cut you.

Laser Toilets? Blender Toilets? Compost Toilets? Oh My!

While we have somewhat made light of the subject, all of these toilets are fantastic products that might scratch that specific itch that you're having on your RV adventures. What we hope to impart more than anything is that there is the perfect option for you out there. With a little bit of research and a bit of a sense of humor, etrailer can help you find what you're looking for to make you feel exactly as you should while sitting on your throne, like royalty.

About Jacob J

To say that my path to etrailer was complicated would be an understatement. I have always had a passion for helping others, and throughout my education and career as a social worker or community liaison, I have loved writing as a hobby. When I found etrailer and was given the opportunity to turn something I enjoyed doing into a career that helped people access information and products they need to live the best life they possibly could, I was instantly interested.

I am a lover of the outdoors, have been loading and unloading trailers since I before I was old enough to drive them, and have spent my recent years working in and around the automotive industry. And I am excited to share all of the things I have learned (more often than not the hard way).

I consider myself a perpetual student, and etrailer gives me the opportunity to learn something new every day and share my findings with others. Which is something I am extremely grateful for. I look forward to continuing to help people find the answers they need to make memories for a lifetime.

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Written By: Jacob J

Last Updated 8/16/22

Brent S.

5/4/2023

This is weird to me.

Mike L.

5/4/2023

@BrentS How so? Do you have a specific question?

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