Best Composting Toilets Review: Waterless Throne Comparisons & Smell Ratings

Updated by Lynda Stevens

Best Composting Toilet ReviewsWhen nature calls, the composting toilet answers! Eco-friendly and functional, these toilets turn human waste into usable, hygienic fertilizer.

After countless hours of research and talking to multiple experts, we’ve narrowed over 17 different composting products, to make sure our top toilet picks are perfect for you.

Our top choices are easy to use, well constructed, and value-conscious to get the best deal for the money. But most of all, we made sure you that your new composting toilet will be completely hygienic and you will avoid horror stories about foul odors.

We’ve separated the paydirt from the stinkers! You can find the best composting toilet to meet your needs in our reviews below.

Here are our favorite composting toilets on the market right now…

Product Details
1. Nature’s Head Dry Composting Toilet with Standard Handle

Overall Best Value

  • Self-Contained
  • Urine Diverting
  • Easy Installation
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2. Separett Villa 9200

Lowest Profile

  • Waterless
  • Urine Diverting
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3. Nature’s Head Self-Contained Composting Toilet with Spider Handle

The Original

  • Compact
  • Great Ventilation
  • Made in USA
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4. Sun-Mar Excel Self-Contained Composting Toilet

Most Expensive

  • Waterless
  • Odorless
  • NSF Certified
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Best Composting Toilet Reviews

1. Nature’s Head Dry Composting Toilet

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The Nature’s Head is built very well, feels sturdy and works very reliably.

In our opinion, the Nature’s Head Dry Composting Toilet is the best composting toilet for the average buyer.

As far as we’re concerned, they met their goal with smashing success! The Nature’s Head is built very well, feels sturdy and works very reliably. We also appreciate that this toilet was more affordable than most of the composting competition. Best of all, it’s easier to install  and to use than other composting toilets.

In short, the Nature’s Head is a self-contained composting toilet system, practical not only for boats but any place where space, plumbing, and electricity is inconvenient or absent. We suggest it for absolutely any application!

We think it offers the best self-contained composting toilet experience you can (easily) buy right now. Short of custom-building your own toilet setup,  or special-ordering a premium Separatt toilet, it’s as close as you can get to perfection.

Fun fact: the Nature’s Head was actually designed by two professional sailors. The creators needed an off-grid, self-contained composting toilet to take off the water, and set about designing something a little more user-friendly than the options that were on the market.

Pros:

One of the best aspects of the Nature’s Head system is the complete lack of smell—both from the toilet unit itself and the compost byproduct. It really does cut the smelly, messy part out of doing your business!

We’re also quite pleased with the construction of the toilet unit, which is simultaneously lightweight and durable. It should last for years of composting! It’s designed to take up very little space, too!

Nature’s Head Dry

One of the coolest features of this Nature’s Head model is the dry composting system. This toilet separates liquid waste and solid waste into different containers. The absence of water in the compost reduces the danger of leaks and odor escaping, while also keeping moisture levels inside the composting chamber ideal for hygienic decomposition.

The separation is a great idea, since the solid waste tank looks and smells like ordinary dirt when you empty it. Since there isn’t an overwhelming toilet smell to deal with, you’ll probably that they only need to empty the solid waste tank very occasionally. That’s especially true if you’ll be using it in a vacation property or cabin.

The Nature’s Head is built very well, feels sturdy and works very reliably.

The best aspect of the Nature’s Head is the price. It’s significantly cheaper than some other composting toilets, despite the fact that we think it works much better.

Cons:

We don’t actually have any complaints about this model. We think it’s the best composting toilet on the market right now by a long shot, aside from the hard-to-find Separett. Still, we figured someone might have found a flaw, so we did some poking around online. Impressively, we couldn’t find any reviews for this one under 4-stars. Most user reviews had no complaints, and the ones who did acknowledge there were only small design features they took issue with.

For instance, one tall user (6”1’) found the toilet was uncomfortable to use. Another wished that the solid waste could be pulled out with a drawer. Instead, the design forces owners lift up the whole unit to remove the compost. That does require a bit of upper body strength, and an injury-free back. However, none of these problems were deal-breakers for the buyers whose reviews we read.

2. Separett Villa 9200

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It’s functionally similar to the Nature’s Head, and there’s no real difference in quality.

Separett has enjoyed popularity in Europe for over a decade, but it’s only recently that the Swedish company has been gaining recognition stateside. Similar to the Nature’s Head, the Separett features a waterless system that brings convenience to remote homes.

The Separett may come with a higher bottom line than the Nature’s Head, but its attractive design and inoffensive maintenance will certainly be worth the extra cost to many buyers. It’s functionally similar to the Nature’s Head, and there’s no real difference in composting quality. The difference is the way you deal with liquid waste, and the way the composting toilet looks in the home. Your decision will probably be based more on aesthetics than functionality, as well as your preference for disposing of liquid waste.

Note: as of this writing, the Separett toilet is unavailable through Amazon and other common retailers, and doesn’t appear to be coming back anytime soon. That’s because the company has a fairly exclusive dealer network, in addition to the fact that this is a pretty niche market to begin with. You can purchase their products from their website, or contact the company for local toilet dealers. We think it’s worth the extra hassle to get, though, because it’s a great model if people are looking for a well-designed, non-dry system.

Pros:

What distinguishes this model from the composting toilet competition is its sleek design and small size–ideal for those people looking for a lower-profile model of composting toilet. You’ll notice that it’s a lot sleeker than either variation of the Nature’s Head toilet!

If you’ll be installing your toilet near an outer wall, and don’t need to worry about freezing, it’s a very nifty solution.

The biggest functional difference is the way the Separett toilet deals with liquid waste. The urine diversion system differs slightly from the Nature’s Head. Instead of running into a container, urine is simply piped outdoors. Solid waste is contained like the other toilets on the market.

Separett recommends a small drain pit for your liquid waste, but it can also be diverted into a container. If you’ll be installing your toilet near an outer wall, and don’t need to worry about freezing, it’s a very nifty solution.

Separett Villa 9200

It’s easy on the eyes inside and out–the interior of the composting toilet has a weight-activated trap door that obscures any waste from view. When someone sits on the seat, the airtight trapdoor swings open. and swings shut again when the user stands. It’s a great feature, particularly for those with delicate sensibilities.

Another benefit for the squeamish: the composting process takes place in a removable bin lined with a compostable bag. Simply remove the bin when it gets full, and let the composting process take place outdoors–instead of inside the toilet.

Like the Nature’s Head, the Separett toilet is lightweight and well-built. At 45 lbs, it’s portable enough to transport to homesteads and vacation cabins without much hassle. Previous buyers said it was a great seasonal toilet option for camps and cabins that don’t have reliable or permanent septic hookups. They also found it very easy to install, thanks to the manageable size and weight.

Cons:

As with the Nature’s Head, we have no complaints about this one. It’s on par with the Nature’s Head for build quality, looks, and all other aspects. Choosing between them is simply a matter of deciding between formats for waste disposal.

Even after browsing through pages of blog reviews and comments, there was absolutely nothing negative to be found about either of the two models of Separett toilet. In fact, the only reason it came in second place on our list is its price tag. At the time of writing it’s pricier than the Nature’s Head toilet, without offering too much more in the way of practicality.

It’s also worth considering that you’ll have a slightly harder time getting hold of one of these than you would if you were to buy a Nature’s Head.

3. Nature’s Head Self-Contained Composting Toilet with Spider Handle

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This one has a modified design that works a bit better in tight spaces.

Does this Nature’s Head toilet unit look familiar? If it does, well spotted! We’ve recommended the same composting toilet twice in this guide–albeit with a few tweaks! The Nature’s Head model we recommended above is the company’s standard toilet model, which is also their best-selling composter. This one has a modified spider handle design that works a bit better in tight spaces.

Pros:

It has the same innovative ventilation system, fan, and modular disposal system as the other Nature’s Head. The only significant difference is the spider handle. Unlike the standard model, this one has a compact spider crank handle like you’d see on a lot of marine applications. The spider handle makes a big difference in spaces where every inch counts!

Nature’s Head Self-Contained

Previous buyers said this toilet was the perfect fit for their small spaces, on land and on water! While you could probably get the other Nature’s Head toilet to work anywhere, this spider handle one requires less clearance, and simply feels better to use in tight spaces.

Since it’s a modular design with simple connections, it’s extremely easy to service.

Like the other Nature’s Head, this spider handle toilet’s all made in the USA from high-quality parts. Reviewers overwhelmingly praised the sturdy build quality, both the cast plastics and the steel fittings. It’s a huge step up in durability over the older Sun Mar’s and other previous composting toilets.

It’s totally self-contained and separated like the other Nature’s Head. You’ll have urine collection bottles and an isolated dry composting compartment.

Since it’s a modular design with simple connections, it’s extremely easy to service. Reviewers said that as long as you’ve got a screwdriver handy, you can make whatever modifications or repairs you need to without trouble.

As with the standard model, the spider handle version is covered by a 5-year warranty.

It also has the same low price as the standard model!

Cons:

Some buyers reported having some issues with the side latches, but they said that replacements were easy to obtain through the warranty process.

*We’re aware that it might seem odd to recommend two Nature’s Head models with only minor differences. There are other brands in the industry, after all, and some of them make very popular composting toilets. However, we’ve seen a big drop-off in quality between our current recommendations and the other options on the market.

For instance, we used to recommend the Sun Mar as one of our top composting picks. It’s the original throne of this kind, and it still has some strong buyer loyalty. The more we’ve looked at it these days, though, the more it seems like it just isn’t up to scratch.

Take a look for yourself, and see what we mean!

reclaimable organic waste

4.  Sun-Mar Excel Self-Contained Composting Toilet

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This signature model is one of the most popular composting models ever to hit the market.

Sun Mar is probably the most recognizable brand in the small but growing world of composting toilets. According to their website, the founder, Hardy Sundberg, is responsible for inventing the self-contained composting toilet in 1971. This signature model is one of the most popular composting models ever to hit the market. Some people still swear by it!

We used to include the Sun Mar in our Top Three, but it’s recently slipped out of our rankings. Here’s why:

Of all the toilets listed here, Sun Mar’s model is the largest. Perhaps “tallest” would be a better word. So tall, in fact, it comes with a stepping stool. It’s certainly less portable than the other two models. That being said, the size does give it high capacity. That used to make it a model worth considering for larger families and long-term users. However, given the user-friendliness of more recent composting models, we think it now seems bulky and unnecessary.

Pros:

Sun-Mar Excel Self-Contained

With some happy owners asserting they’ve used the Sun Mar Excel for over a decade, there’s no doubt these composting toilets stand the test of time when maintained properly. Previous buyers said their units were still going strong after more than a decade of regular use. That’s especially impressive given that many reviewers had installed their Excel’s in harsh environments, up in the mountains or in backwoods cabins.

This is the only model that features a drum for tumbling compost since Sun Mar has an international patent on the technology.

This is the only model that features a drum for tumbling compost since Sun Mar has an international patent on the technology. That makes it an excellent choice for people who process lots of compost for a garden since it keeps everything going steadily. Again, the Sun Mar has a higher capacity than the other two toilets we reviewed.

Cons:

The Sun Mar Excel just doesn’t seem worth the extra money. This unit has overwhelmingly poor reviews and lots of complaints on all online retail sites, and there are horror stories from people who have tried it out. It was certainly great when it was the only game in town, but now other companies are doing it better.

There were many complaints about the plastic crank that is used to tumble the compost drum. While previous buyers said the company shipped out replacements at no cost and with no hassle, frustrated customers eventually ditched the company handle and installed a metal aftermarket handle to solve the problem once and for all. It’s one of those design issues which later models from other companies have solved.

Some users also complained quite a bit about the smell. While others insisted that proper use should leave the unit odorless, the high number of complaints indicate that the Sun Mar Excel isn’t nearly as user-friendly as the other models–with grim results for people who fall outside the learning curve.

Cleaning was also reported as unhygienic, and there were a number of complaints about mold and bugs. Previous buyers said that because the contained toilet design was a breeding ground for black flies and mold mites, cleaning the unit was an unsanitary struggle which was best avoided. People said that while the situation was manageable if users knew precisely how to use the unit, it could get out of control if the SunMar was left sitting for several days in a row. If you want you can use a shower cleaner as an alternative. 

Conclusion

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Which of the models featured in this buying guide should you buy?

    • Nature’s Head (standard)
    • Nature’s Head (spider crank)
    • Separett

*At twice the price of our top pick–and with far more user complaints—there’s little incentive to purchase the Sun Mar Excel over the Nature’s Head or Separett. Sun Mar may be the original self-contained composting toilet, but this “throne” has been usurped. 

Most buyers will want to choose between one of the Nature’s Head toilet models and a Separett.

We think the Separettis the best composting toilet, but it’s not as convenient to buy or affordable to purchase as a Nature’s Head. If you can pony up the extra cash, and are going to make lots of use of your composting toilet, go for the Separett.

If you want the convenience of being able to buy a composting throne on Amazon, and the extra $500 or so in savings, you won’t be missing out on much by going with a Nature’s Head. Both versions of this setup are user-friendly, effective, and reliable. We think they’re better choices for the average buyer, if not the absolute best.

The upside of all the interest in composting toilets these days is that the choices are getting better and better! Anyone of these three toilets will serve people well.

If you’re choosing the best composting toilet for your needs, we would suggest you try the Nature’s Head model for its incredible value for money.

What to Consider When Buying Your Composting Toilet

Local Laws

Before purchasing anything, you should review the local laws governing waste disposal at your location. Unfortunately, composting toilets are relatively new and unknown. Certain states and municipalities haven’t updated their laws to account for hygienically-treated human waste. You might be fined in these locations for using your compost toilet.

So, double-check with a local authority before you start to use one. Generally, anyone in a rural area with plenty of their own land won’t need to worry. They’re made for rural spots and cabins anyway. However, you can imagine that most urban and suburban areas aren’t going to be especially enthusiastic about a neighbor composting poo in the back yard.

Certain states and municipalities haven’t updated their laws to account for hygienically-treated human waste.

Space

These are pretty big things to install. They have a much bigger footprint than your average throne, even if they don’t require any piping. For homes on the move–like tiny houses, RVs and trailers–space is a precious resource. Make sure to review the dimensions of your prospective toilet, and compare them to your available space.

They have a much bigger footprint than your average throne, even if they don’t require any piping.

Capacity & Maintenance

Your own attitude towards maintaining your composting toilet and the byproduct should weigh in. Some composting toilets are user-friendly, while others require users to carefully study the manual to avoid worst-case scenarios.

Some toilets will need to be emptied more often than others. Consider the number of people who will use the toilet, and how long they will be using it. Figure out which approach is the best for your lifestyle and personal preferences.

Some toilets will need to be emptied more often than others.

Electricity

Unlike a traditional indoor fixture, composting toilets usually need an electrical hookup to work properly. Each model listed above requires electricity to run, as do the competition. If that’s a concern for your location, don’t worry! Most also have versions aimed at users without a steady stream of electricity.

For example, the Separett Villa 9210 toilet can be used with a battery and/or solar power. The Nature’s Head toilet has a “self-contained” version that doesn’t require electricity, and the Sun Mar Excel has a “non-electric” model.

Each model listed above requires electricity to run, as do the competition.

Buyers Also Asked

Why Use a Composting Toilet?

Properly set-up compost toilets have a very low ecological footprint. As water usage concerns grow, it’s worth pointing out that traditional toilet systems can use roughly 30% of a household’s water consumption.

Replacing your flush toilet with a composting one can save more than 6,600 gallons per year for each person who uses the bathroom! The EPA has an informative brochure on the environmental impact of composting toilets.

How Do Composting Toilets Work?

Composting toilets operate much like the composting system you’d use in home gardens. They help accelerate decomposition and leave you with a manageable, productive waste material. The final product is odorless and dry, more or less the same as commercial fertilizer you might buy in a home and garden store.

Depending on your state’s laws, this can be buried safely in the ground or near the base of non-edible plants in your garden. If you’re an avid gardener, this is a great way to supplement your kitchen scraps with some extra fertilizer. We have a full guide to how composting toilets work here.

how do composting toilets work

Do Composting Toilets Smell Bad?

When considering the switch from a traditional toilet, a central concern for many consumers is the threat of odor. The idea of a non-flushing toilet might conjure up memories of the horrid stink of a porta-potty or an old-school outhouse.

Those fears can be put to rest. Modern composting toilets (if set up correctly) are 100% odorless and hygienic. They use sophisticated airflow systems and seals to neutralize any smells. Composting toilets have proven so effective at eliminating odors, some higher-end models have replaced traditional toilets in eco-conscious suburban homes. Try installing a faucet for water purpose. 

What’s Next?

Use our reviews and buying guide to pick the best composting toilet to meet your needs. You can also compare and contrast the best toilets on the market using our guides and lists.

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