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Before we even bought our first RV, we knew we wanted a composting toilet for the RV. Traditional RV toilets sounded scary – especially the part about dumping sewage from the black tank out through a hose. (As we later found out, dumping the black tank really isn’t so bad!)

We read countless articles about different kinds of RV toilets, and composting toilets jumped out at us (well, at me) as the obvious choice.

In the end, our adventure with a composting toilet lasted only two weeks. In retrospect, we shouldn’t have gone from a residential toilet straight to a bucket toilet, but …. Live and learn. We use a portable toilet now, if you’re interested in checking that out.

But we have used quite a few types of RV toilets and we want to help you learn from our successes and our mistakes. Composting could have gone great for us, if we’d known a bit more at the time.

To help you decide if it’s right for you, here’s everything we know about composting toilet for RVs – including the 6 best composting toilets available to RVers.

What is a Composting Toilet?

Best Composting Toilets
Photo credit: Nature’s Head

A composting toilet is a type of toilet that doesn’t use any water for flushing. Instead, it usually separates the liquids (#1) from the solids (#2) to prevent your waste from turning into sewage. (That’s where the smell comes from.)

The liquids go into a bottle, which can be emptied on its own into a toilet, or diluted and sprinkled onto the ground.

The solids get mixed in with peat moss, coconut coir, or some other organic medium. This dries them out, keeps odor down, and starts the decomposition process for your waste, which eventually turns it into compost. You know – the stuff you can use as fertilizer.

When the compost bin fills up (typically this takes a few weeks), you can empty it into a compostable bag and just toss the whole thing into the trash.

Why use a Composting Toilet in your RV?

composting toilet for rv
Photo credit: Separett

There are lots of benefits to using a composting toilet while RVing. That’s why we were so convinced at first that we needed one! Here are the main reasons why we wanted a composting toilet.

Eliminate Black Tank

Our Class A motorhome came with a Dometic® 310 China Bowl Stool connected to a 40 gallon black tank. We figured we’d need to dump the tank every 7-10 days or so with the two of us living in it full time. That’s a lot of trips to the dump station to empty sewage from the black tank. (Granted, we’d still need to go to the dump station to empty the gray tank, but this would let us go longer between trips.)

Also, remember that scene in RV with the sewer line explosion? We’d heard so many horror stories about dumping the black tank that we were wary about trying it at first. Using a composting toilet in your RV allows you to skip that whole process, since your waste isn’t entering your RV’s holding tanks at all. There’s no need to deal with sewage in the “stinky slinky.”

Save Fresh Water

Composting toilets do not require water. They are dry toilets that use organic materials to treat human waste. For us, that meant the 75 gallon fresh water tank would last longer for showers, dish-washing and of course for drinking (which we run through a water purification system – read our Berkey Review).

If you’re boondocking or dry camping out in the wild, you know that water is a precious resource. We thought that if we could save the water we might otherwise use to flush our toilet, we could stay out longer especially if it’s an epic spot.

Increase Gray Tank Capacity

Not using the black tank for a traditional RV toilet would give us the option to combine it with the gray tank and use it as an overflow. This would allow us to increase our gray tank capacity. Again, the fewer trips to the dump station, the better.

For those taking on a DIY van build, you may be install a bigger gray tank or use that valuable space for other components.

Other Benefits

  • Reduced Odor: This wasn’t our experience, but we’ve read a lot from people who have found that their composting toilet smells less than their traditional water-flush RV toilet. This is because you’re separating liquids from solids, and it’s the combination of both that create that sewage smell.
  • Eco-friendly: Because you aren’t using fresh water to flush, you’re not only preserving water to allow you to camp longer – you’re using less water in general.

The 6 Best Composting Toilet for RVs

1. Nature’s Head Composting Toilet

Cost: $960
Solid Capacity: Full time for two is approximately 60 to 80 uses for 3 to 4 weeks
Liquid Capacity: 2.2 gallons
Features: 12 volt fan
Warranty: 5 years
Made in USA

The Nature’s Head is the most popular composting toilet on the market. It’s relatively easy to install (as long as you can vent to the outside in your RV), as it has a 12-volt fan to keep odors down.

It’s not the most expensive (nor the least expensive) composting toilet on the market, and it’s lightweight and has a smaller footprint than other brands.

The customer service is reported to be excellent which is always important when spending this kind of money on a product that you’ll be using daily.

Nature’s Head was the brand we were seriously considering before we tried the composting bucket toilet.

2. Air Head Dry Composting Toilet

Cost: $1,029
Solid Capacity: Full time for two adults is approximately 60 uses for 1 month
Liquid Capacity: 2 gallons
Features: 12 volt fan
Warranty: 5 years
Made in USA

The Air Head markets itself as the most compact composting toilet available. The cost and capacity are similar to the Nature’s Head, but the footprint of this toilet might work better in a smaller RV.

3. Separett Composting Toilet

Cost: $989
Solid Capacity: Full time use for a family is approximately 3 weeks
Liquid Capacity: 50L ejector tank
Warranty: 5 years

Separett is a manufacturer in Sweden that makes several urine diverting composting toilets for use in RVs. The model that is commonly sold in the U.S. is the Separett Villa 9215.

4. C-Head Portable Composting Toilet

Cost: $649+
Solid Capacity: Full time for two is approximately 10-12 uses for 1 week
Liquid Capacity: 1 gallon
Warranty: 30 day return policy on unused units

The C-Head composting toilet comes in a wider variety of sizes and colors than other brands we found. You can opt for different stains and types of wood base, as well as different shapes (some are designed to fit into corners, etc.). If you have a very specific bathroom layout or look, this might be your best option. But watch out for tank capacities, since the C-Head holds less and will need to be emptied more often.

5. Sun-Mar Mobile Composting Toilet

Cost: $1,775
Solid Capacity: Full time for one adult or families of two
Liquid Capacity: n/a has an evaporation chamber
Features: 12 volt fan & 110 volt heating element
Warranty: 5 year on fiberglass tank and 3 year on all other parts

The Sun-Mar is one of the more expensive options on the market, but it’s also one of the fanciest. Most composting toilets have a very simple design: a bottle for liquids, a holding container for solids and whatever organic matter you choose to add, and a small fan to divert odors outside.

The Sun-Mar takes things a step further and focuses on optimizing the composting process, so they’ve patented a special Bio-Drum with an evaporation chamber that helps speed the breakdown of solids into compost. An added plus is that there’s no need to empty your liquids, since the toilet evaporates them for you!

6. Bucket Composting Toilet

Cost: $10+
Solid and Liquid Capacity: 5 gallons

This was the first (and only) composting toilet we tried, because we couldn’t find a good place to vent a more elaborate setup in our first RV.

It’s by far the most affordable option, especially if you don’t care much about how it looks in your bathroom. We dressed ours up with a box to hide the bucket and put a toilet seat on top, but you can go pretty simple with this one if you’re feeling adventurous.

While you can use a bucket composting toilet without diverting the urine, it requires figuring out the the right material such as sawdust to dry everything out and prevent bacterial growth. When the bucket is full, just empty into a trash bag and start over again!

To divert the urine in a bucket composting toilet, you will need to buy an aftermarket urine diverter. At $45, it is still much more affordable than the urine diverting toilets listed above.

The bucket toilet wasn’t for us in the long run (we like our portable RV toilet), but if you’re interested in using one as a composting toilet for your RV, check out The Humanure Handbook. It’s an extremely helpful resource.

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Things to Consider Before Getting a Composting Toilet for Your RV

1. Space

The first thing we did was measure the available space to install a composting toilet in the RV. These toilets can get pretty expensive, so it’s very important to measure twice (or more) to make sure the toilet will fit before you buy.

2. Installation

Many composting toilets require ventilation and power for the fan. You’ll want a way to wire the fan into your onboard electric system, and also a good place to route the vent hose from your bathroom to the outside. Be aware that this generally means cutting a hole in the wall of your RV.

3. Organic Material

To put it simply, organic material is what helps dry your poop and turn it into compost. It’s a very important part of the process! Make sure you have a place to store materials such as sawdust or coco fiber, which can take up a lot of space. Another thing to consider is sourcing. Will you be camped in places where you can buy these materials as you run out?

4. Cost

There is a significant difference between the $10 DIY bucket toilet and the $1k+ toilet. After taxes, shipping and installation, an RV composting toilet could end up costing a lot more than expected. Make sure it’s worth it to you before you invest.

5. Dumping

No matter which toilet you choose for your RV, you’re going to have to empty it somewhere. (If you find a way around this, let us know.)

Dumping a composting toilet is different than dumping a traditional toilet.

While you don’t have a black tank of sewage to manage, you still have to find an appropriate place to dump the liquids. This might mean carrying a bottle of your pee through a parking lot to a public toilet or pit toilet to dump it. There is also the option to connect to a grey tank system in the RV.

For the solids, you’ll need to empty the bin into a bag for disposal in a trash can. Make sure to check with the waste management company in your area for proper humane waste disposal. If you’re looking to add the solid waste to a compost pile, make sure to do your research. Properly composting human waste has different temperature requirements among other things. Again, you will want to check the local ordinance on composting human waste.

6. Capacity

As with any RV toilet, a solo traveler or a couple will take more time to fill up a composting toilet than a big family. If you have lots of people making “deposits,” it’s very possible that you could fill up the solids bin before the waste has had time to turn into compost. Something to keep in mind when thinking about the emptying process.

Composting Toilet FAQs

If you’re just looking for some quick answers to your most burning questions about composting toilets, you’ve come to the right place. Here are some short and sweet answers to all of the most common questions about composting toilets that we can think of.

How does a composting toilet work in an RV?

Basically, a composting toilet separates liquids from solids, which means that you don’t end up with any sewage.

You’ll have a separate liquid tank, which can be dumped in any public toilet or sewer drain, and a solid compost bin, where your solid deposits get mixed with composting material to form humus. (NOT to be confused with hummus—this is just the organic material you find in fertilizer that helps plants grow.)

How do you use a composting toilet?

In much the same way that you use a regular toilet, except that you do have to be careful not to mix any liquids and solids together when you “go.” This can be more difficult for women than for men.

When you’re finished, the flushing process is similar, except that you’ll use little to no water. You’ll also have a hand crank or something similar to mix your newest solid waste in with your composting material.

How much does a composting toilet cost?

As with just about anything in the world of RVers, you can spend as much or as little as you want. We’ve seen toilets as simple as a 5-gallon bucket full of sawdust, with a makeshift seat on top, all the way to an elaborate toilet that runs on electricity and costs thousands of dollars.

The composting toilets listed above are actually a good representation of what’s out there in terms of price for urine diverting composting toilets.

What is a composting toilet system?

Well, it’s a system for using your toilet to compost! All joking aside, a composting toilet is a means of turning your waste into usable material, conserving drinking water, and avoiding the need to dump any sewage from your RV’s black tank.

Do you have to empty a composting toilet?

Only if you want to keep using it … With a composting toilet, liquids and solids go to different places. You’ll need to empty the liquid bottle more often, since it’s got a smaller capacity and isn’t breaking down the way your solids are. But you will need to empty your solids, too.

And here’s how …

How do you empty a composting toilet?

Liquids can be dumped into a public toilet or sewer, or diluted and scattered on the ground (depending on where you are).

Solids will slowly decompose in your tank until they’re well on their way to becoming fertilizer. At that point, just put the whole bin’s worth of “stuff” into a compostable bag and toss it in a dumpster.

What do you do with composting toilet waste?

There’s not much you can do with the liquids (apart from dumping them), but you can do some cool stuff with the compost that comes from your solid waste. Because it gradually breaks down into fertilizer, you could use it on any plants you travel with, or on a home garden if you still have a sticks and bricks home.

Of course, you can also just toss it. The choice is yours.

How often do you have to empty a composting toilet?

Without getting too graphic, this depends on how many people you have, and how much all of those people eat and drink. On average, we’ve seen that liquid bottles tend to fill up in 2 days or so with 2 adults using the toilet full time. Solids take longer—maybe 2-3 weeks for 2 adults.

Summary

Overall, composting toilets can be a great option for RVers. They aren’t as portable as a porta-potty or a cassette toilet, but they’re a more portable option than the traditional porcelain (or plastic) bowl. They are enormous water-savers, and can be more pleasant to dump than other RV toilets (though you will likely be dumping liquids more often).

If you’re trying to decide what kind of toilet to use in your own RV, check out our articles on other traditional RV toilet alternatives: cassette toilets and portable toilets.