Should I Get a Composting Toilet in My RV?

It’s no mystery that RV toilets don’t have ornate plumbing systems. Rather than fight with your blackwater tank all the time, you’re thinking of switching to a composting toilet for your RV instead. Is this the right move?

Composting toilets can go weeks at a time before you have to take care of waste removal. The removal process is manual compared to draining a blackwater tank, and composting toilets are often costlier than other RV toilets.

Deciding whether you’ll use a composting toilet in your RV is a big choice, and we’re here to make yours a little easier. In this extensive guide, we’ll discuss how composting toilets work, their cost, and the pros and cons. You won’t want to miss it. 

What Is a Composting Toilet? How Does It Work?

First, let’s make sure you understand composting toilets in full. 

Composting Toilets 101

Have you ever heard of composting? If you have, that’s the crux of a composting toilet. If you haven’t, let’s explain it now.

To compost something is to allow organic materials to decompose into compounds. If you have a garden at home, you might use a compost pile for some of your plants. You’d know then that manure is a primary ingredient in compost, but it doesn’t only have to be animal manure.

A composting toilet takes your human feces (as well as urine) and breaks it down. You don’t have to flush one of these toilets, and they have no water in the tank either. Instead, you’re supposed to add peat moss, coconut coir, sawdust, or another carbon additive to the toilet. By doing this, you introduce pockets of air throughout the inside of the toilet that starts the decomposition process.

For composting to happen, you need a ratio of carbon to nitrogen that’s at least 25:1. The temperature of the composting toilet must be 104 to 122 degrees Fahrenheit or 40 to 50 degrees Celsius. Active mixing and chamber dimensioning can help to that end. You also cannot exceed 70 percent moisture.

Composting toilets include a composting or collection unit and a seat. Some toilets only let you squat rather than sit, but that depends on the design. The composting unit is more complex, as within it is the access door for taking compost out, a urine diversion system or leachate collection, a ventilation system, and the composting and storage chamber. 

Composting Process of Self-Contained Composting Toilets

When you use a composting toilet, what happens? Well, first you do your thing. If your composting toilet has a urine diversion technology or leachate collection, then it will hold the urine there. The feces will go in the composting and storage chamber. Not all composting toilets include a urine diversion system though, in which case, urine also travels to the composting chamber. 

Between the urine diversion system and the carbon additive you used in the toilet, aerobic decomposition can occur. If the decomposition process is a smooth one, there’s usually not a lot of smell involved in a composting toilet. 

Fungi and bacteria, collectively known as microorganisms, break down the content in the composting toilet until you have an end-product that’s often likened to humus. No, not hummus the food, but humus, a type of amorphous organic soil. 

If you wanted to, you could take the end-product and add it to your soil back home. That said, check the regulations in your neighborhood before you just dump human waste into your yard. This practice is sometimes not allowed, as prescription medication residue from an assortment of medications may be left in the compost that can get into groundwater. 

Some of the more common medications that have been detected in groundwater are cholesterol-lowering medication, fibrates, carbamazepine, caffeine, ibuprofen, testosterone, progesterone, estrogen, digoxin, calcium-channel blockers, ACE inhibitors, blood thinners, antidepressants, and antibiotics. 

We have to talk about pathogens, as they tend to survive in composting toilets. Ascaris eggs, a type of helminth egg, are one such frequent pathogen. Ascaris, by the way, is a parasitic roundworm species. Not all Ascaris worms spread to people, but the Ascaris lumbricoides can. It causes ascariasis.

This small intestine infection can spread to the lungs in severe cases. While the worms are still in your small intestine, the symptoms include weight loss, abdominal pain, lack of appetite, diarrhea, vomiting, fecal changes, and nausea. 

When you go to the bathroom, you might see worms in your feces. Intestinal blockages can also sometimes happen, which will increase your rate of vomiting and abdominal pain. If your children have ascariasis, their growth can be impeded.   

Should the worms reach your lungs, symptom severity increases. Now you may experience fever, pain and discomfort in the chest, bloody mucus, wheezing, gagging, and coughing. In some cases, people have reported aspiration pneumonia, a type of pulmonary aspiration where saliva or stomach acid can be redirected to the lungs.

What Are the Advantages of a Composting Toilet?

Now that you understand the basics of composting toilets, it’s time to delve into the pros and cons. In this section, we’ll talk about why so many RVers rely on composting toilets. 

No Need to Use Your Black Tank

The blackwater tank is probably the bane of your existence as an RV owner. You don’t mind flushing and cleaning the freshwater tank since it never gets too dirty and it doesn’t contain human waste. Even the graywater tank–while certainly not appealing–isn’t particularly offensive. But the blackwater tank? You rue the day you have to filter all that dirty, fecal wastewater out of the tank at a dump station. It doesn’t matter how many times you do it; dumping it never gets easier.

With a composting toilet, you’ll stop using your blackwater tank altogether. A composting toilet has no sewer system, no septic system, and no tank connections. Everything goes straight into the toilet. You’ll still have to flush your graywater and freshwater tanks from time to time, but you won’t be at the dump station nearly as often anymore. 

Longer Periods Between Dumping – Great for Boondocking

How long can you go before you have to empty your blackwater tank now? It’s probably no more than three days, right? Maybe on the rare occasion, you can wait five days, but you’re still dumping the contents at least every week. When you go road-tripping for a month or longer, that’s a lot of dumping to have to do. 

Composting toilets can hold onto at least two weeks’ worth of waste and others three to five weeks!

Let’s say you have a two-month road trip planned in your RV, which is eight-and-a-half weeks. That’s nearly nine times you’d have to dump your blackwater tank. With a composting toilet, you could dump three to six times. Yes, that’s right, you can halve your dumping rate with a compost toilet.  

They’re Big 

Those cassette toilets don’t feel like your potty back home mostly due to the size disparity. Cassette toilets might be 29 inches by 17.25 inches by 21.75 inches. Compare that to your commode at home, which is on average 30 inches by 31 inches by 20 inches. 

Composting toilets are more akin to the size of a home toilet than a cassette toilet. When you have to go, you want to be comfortable. A composting toilet will prioritize your comfort in a way that you don’t always get with cassette toilets.  

Composting Is Sustainable 

You love RVing, but you know driving your hulking vehicle all over the country doesn’t exactly help your carbon footprint. That’s why you try to be as eco-friendly as possible. Owning a composting toilet is about as sustainable as it gets. The waste you make could be reused to help plants grow and flowers bloom. 

What Are the Disadvantages of a Composting Toilet?

As beneficial as composting toilets can be, we must talk about the downsides of using one of these toilets. 

Can Be Stinky

Although aerobic disposal is supposed to be a relatively stink-free process, that doesn’t mean odors won’t get through. Besides, aerobic decomposition only occurs when certain criteria are achieved as we discussed at the beginning of this guide. If your carbon-to-nitrogen ratio is off or the moisture levels aren’t within the right range, then your whole RV will start to smell like feces and/or urine quickly.

Sure, you could empty a bottle of air freshener in the RV, but that only masks the odor. You’d have to open the windows and let the smell slowly waft out. When staying at a campsite or state park with other RVers, you can bet they’re going to complain. 

They’re Expensive

Composting toilets are far from cheap. They start at $1,000 and may cost upwards of $1,400. A basic cassette toilet, on the other hand, is priced at $100 to $300. You might pay between $500 and $700 for a really high-end cassette toilet, but they’re always less costly than a composting toilet. 

You already have plenty to spend money on as an RV owner. You might decide to draw the line at a $1,000 toilet, and we can’t blame you! 

You Have to Directly Remove the Waste

Yes, a composting toilet does prevent you from having to empty your blackwater tank, but all the waste that goes in your toilet can’t stay there forever. The storage chamber only has so much room, and when it’s full, bad things will happen. Urine can leak, sometimes even before the tank is full, so you must be diligent about emptying it.

Since composting toilets are tankless, how do you get rid of the waste, anyway? Many composting toilets have a tray under the storage chamber that you can pull out. Then you can bag up the composted waste and do what you wish with it. 

If you’re not allowed to sustainably reuse the compost, then you can leave it at an RV dump station or flush it down a public toilet.

When you remove the waste, sometimes it will still be fresh feces. Other times, the waste will have composted enough that it’s more manure-like. Either way, you have to get really comfortable with handling your own waste. 

Could Lead to Pathogen Spread 

Besides the ick factor, there’s also the risk of pathogen and disease spread if you improperly handle the composting waste. You could get very sick and spread worms and other pathogens to your fellow RVers, which is no fun for anyone. 

Waste Disposal and Cleaning

When you need to “dump” the compost from the toilet, follow these steps.

  1. Get your gloves on
  2. Lift off the lid
  3. Take off liquid bin (should be dumped when you its about 3/4 full, but some models have built-in liquid sensors)
  4. Check local regulations and laws for dumping the liquid. I typically dump in a public toilet.
  5. Get a composting bag or trash bag and place around the compost bin. Pick up the toilet and turn upside down so the contents fall into the bag.
  6. To clean, use a vinegar and water mixture in a spray bottle or some other detergent and spray it clean.

Should You Get a Composting Toilet in Your RV?

Okay, so let’s address your question, shall we? Is a composting RV toilet the right option for you?

Composting toilets are certainly convenient. If you already use compost as part of your indoor garden, then figuring out a composting toilet on your RV should be easy. For those who are new to composting, you can still get one of these toilets, there will just be a steeper learning curve. 

If you want a composting toilet so you never have to touch your blackwater tank again, we’d encourage you to reconsider. The waste removal process in a composting toilet is a lot more in-your-face than sending sewage through a blackwater tank. You have to pull out a tray full of feces, and for many RVers, that may be worse than emptying a blackwater tank. 

Consider your budget as well. Composting toilets start at $1,000. They can last for years with the right care, but you’ll consistently have to replace the carbon additive. Peat moss starts at $1.10 per cubic foot. Coconut coir is about $20 for an 11-pound bag. Sawdust is $20 for five pounds. These additives aren’t particularly expensive, but the costs can add up over the months and years.

If you do decide you want a composting toilet for your RV, you need to be ultra-careful whenever you handle waste to avoid pathogen spread. We always recommend wearing gloves and other protective equipment such as goggles or a face mask if you don’t want to breathe in bathroom odors. Make sure you thoroughly wash your hands when you’re done handling the waste.

Can You Put Toilet Paper in the Composting Toilet?

Yes! You can absolutely put toilet paper in it. In fact, it is a crucial component of the composting process. The paper serves at the carbon source while the waste serves as the Nitrogen. Any toilet will work unlike your RV’s toilet that needs special kind of TP. However, if you do use marine or RV TP it will break down much faster than your typical Charmin or Cottonelle.

Most Popular Options for Composting Toilets

Final Thoughts 

Composting toilets are an eco-friendly, tank-free solution. They last for weeks at a time rather than days like a blackwater tank, but you have to often get up close and personal with your waste. 

We hope this guide helped you decide whether a composting toilet is the right pick for your RV! 

Geoff Southworth

I am a California native and I enjoy all the outdoors has to offer. My latest adventures have been taking the family camping, hiking and surfing.

Recent Posts

outdoortroop-21 outdoortroop-20