Best Composting Toilets – Top 6 Picks in 2021, Reviews and Buying Guide

by Dan | Last Updated: January 15, 2021

Our editors independently research, select and recommend the best products. Some of these may be affiliate based, meaning we earn a small commission (at no additional cost to you) if items are purchased.

Although relatively new in the US, composting toilets are not a strange thing in the Eastern world. The ever-increasing demand for conserving water coupled with the increase in population, however, is slowly changing people’s perception of these systems around the globe.

It’s also very likely that you are reading this best composting toilet system write-up since you are harboring the thought of purchasing one.

But why would you want to go waterless with your toilet? Do composting toilets really work? Are they worth going for? You ask.

Now, these are some of the questions that I’ll be offering in-depth information for in the buying guide section (after the reviews). Read on!

However, at a glance, you may want to consider a compost toilet if:

Top 6 Composting Toilets

Best Overall
Nature's Head NH-SPH
  • Nature's Head NH-SPH
  • Our Rating: 9/10
  •  Shape & Color:
    Elongated
    Granite
  •  Dimensions:
    22x20.5x21.7"
  •   Features:
    Odor Free Operation And Ease Of Disposal, All Stainless Hardware
  • Price: 
Premium
Sun-Mar Excel Non-Electric
  • Sun-Mar Excel Non-Electric
  • Our Rating: 8/10
  •  Shape & Color:
    Round
    White
  •  Dimensions:
    36x36x28"
  •   Features:
    Non-Electric Model, Uses No Water, 100% Non-Polluting
  • Price: 
Budget
Saniflo 023 SaniCompact 48
  • Saniflo 023 SaniCompact 48
  • Our Rating: 8/10
  •  Shape & Color:
    Elongated
    White
  •  Dimensions:
    18.2x14.5x15.8"
  •   Features:
    Easy to Install, Quiet, Adjustable
  • Price: 

1. Nature’s Head NH-SPH – Editor’s Choice

It’s Comfortable and Easy To Use

Nature's Head NH-SPH

Established in 2006, Nature’s Head is among the best composting toilet brands in the USA. This brand was started by 2 long-term sailors who were in need of an eco-friendlier crapper for the harsh marine environment. Learn more about this brand here.

The Nature’s Head NH-SPH is an impressively designed toilet meant for off-grid properties. Its compact, self-contained design also makes it a great option for RVs, campsites, and even trucks.

How Much Waste Does It Hold Sanitarily?

Allow Up To 80 Uses

The Nature’s Head NH-SPH measures 22 x 20.5 x 21.7 inches. It has a large composting chamber that can allow up to 80 uses before the need to empty. For 2 users, this means that you can go up to 5 weeks before emptying.

This Head has a separate chamber for the liquid waste that requires emptying regularly. Past users report emptying it every other day. Fortunately, emptying is really easy. I would also advise you to get an extra liquid chamber if you don’t want to get out in the middle of the night.

The nature’s Head NH-SPH features an elongated bowl that is said to be more comfortable for adult users. In addition, this commode is also tall and, therefore, comfortable for tall adults and the elderly. Kids might require a ladder to get on and off the throne.

No Odors Whatsoever!

It’s also worth mentioning that the NP-SPH does not fill your compact bathroom with bad smells. This system uses peat moss and has an easily rotatable spider arm. It also has an electric fan and comes with a vent hose for optimum air exchange.

[easyazon_link identifier=”B009Z7EKIC” locale=”US” tag=”toptoilets-20″]Check Price At Amazon[/easyazon_link]

2. Sun-Mar Excel Non-Electric – Premium Pick

Sun-Mar Excel Non-Electric

Does Not Require Water or Electricity

Sun Mar has for long been the go-to brand for most North Americans. This manufacturer is known for its slightly different approach in composting toilets.

Larger Holding Capacity

Unlike Nature’s Head units, Sun-Mar builds their toilets with a large bio-drum. Their toilets are, therefore, notably bulkier than the competition. Although this bulky design speaks volume about the required installation space, it also means a larger holding capacity.

This Sun-Mar Excel, for instance, measures 36x36x28 inches. Although relatively larger than the Nature’s Heads, the Excel will still fit in most tiny bathrooms without cluttering them up. On the upside, its large bio-drum can support by up to 7 users for a full weekend.

Another good thing about the Sun-Mar Excel is that it does not require water or electricity. This means that unlike the Nature’s Heads above, you won’t need to plan for electrical wiring with this one. Again, its no-electricity design also means that you can live off-the-grid much more easily. You won’t be purchasing batteries or solar panels either.

Weights 90 Pounds

The only issue with the Excel is its heavyweight design. At 90 pounds, moving this system regularly won’t be fun at all. Again, its tall design could make it a little bit challenging for short people.

Luckily, Sun-Mar solves this with a stool.

[easyazon_link identifier=”B001CFQFL0″ locale=”US” tag=”toptoilets-20″]Check Price At Amazon[/easyazon_link]

3. Saniflo 023 SaniCompact 48 – Budget Buy

Does Not Require A Holding Tank

Saniflo 023 SaniCompact 48

Similar to our first 2 recommendations above, the Saniflo 023 SaniCompact also allows you to set up a toilet where a regular commode won’t. These places include under stairs, basements, and anywhere else below the sewerage line.

The only difference is that the SaniCompact is a macerating toilet. A macerator toilet has a motor either under the bowl or behind it.

This motor uses blades to blend your solid waste and toilet paper into sludge before pumping it either vertically or horizontally towards a sewer line.

Uses 1 Gallon Of Water Per Flush

Unlike a composting toilet, the SaniCompact 48 uses 1 gallon of water per flush which is slightly lower than most flushing toilets. The best part is that this system is connected to your waterline.

The flushing mechanism is totally automatic and does not require a holding tank.

Needless to mention, a macerating toilet is only ideal for a home with a dedicated plumbing system. You might want to consider other options if you want something portable.

The good news is that it does not require emptying as it’s the case with composting toilets. However, regular professional maintenance is vital.

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Nature’s Head NH1
  • Nature’s Head NH1
  • Our Rating: 8/10
  •  Shape & Color:
    Elongated
    White
  •  Dimensions:
    19.8x20.8x20.5"
  •   Features:
    User Friendly, Easy Installation, All Stainless Hardware
  • Price: 
Nature's Head Spider 2
  • Nature's Head Spider 2
  • Our Rating: 8/10
  •  Shape & Color:
    Rectangular
    Granite
  •  Dimensions:
    17.8x17.8x21.5"
  •   Features:
    Easy To Install, Absolutely No Odor, No Maintenance
  • Price: 
Saniflo Saniaccess 2
  • Saniflo Saniaccess 2
  • Our Rating: 8/10
  •  Shape & Color:
    Oval
    White
  •  Dimensions:
    Check With The Manufacturer
  •   Features:
    Possible Connections: Toilet & Sink ONLY
  • Price:  i class="fa fa-dollar">

4. Nature’s Head NH1 – Lighweight Toilet

Elongated Style For Easy Use

Nature’s Head NH1

Nature’s Head NH1 is hard to tell from its other siblings on this list. The only notable difference is its z-shaped hand crank agitator. This handle offers smooth operations and can be turned by anyone including your 3 yo.

About design, the NH1 resembles any other compost toilet from this manufacturer. It has a comfortable molded throne with an elongated style for easy use. It’s also taller than your regular conventional toilet and, therefore, a good relief if you have trouble using a short crapper.

Lightweight at 27.2 lbs

The NH1 is also notably lightweight than our previous recommendations at 27.2 lbs. Previous buyers report that it’s extremely easy to switch its locations. This lightweight design also means that emptying the solid chamber is also easier.

About installation, the NH1 comes with everything that you need to get it firmly supported on the ground. You’ll also get a 5-inch vent hose for the ventilation shaft. It also has a 12v power plug but can also use a 12-volt battery powered by a solar panel.

[easyazon_link identifier=”B003EX7LV6″ locale=”US” tag=”toptoilets-20″]Check Price At Amazon[/easyazon_link]

5. Nature’s Head Spider 2 – Affordable and Popular

Nature's Head Spider 2

Up To 5 Weeks Before Emptying The Solid Waste Chamber

In case you need something compacter than the NH-SPH above, then I would highly recommend that you check out the Nature Head’s Spider 2. This one measures 17.8 x 17.8 x 21.5 inches and will take lesser space in your sailboat and RV.

Uses A 12 Volt Fan

Other than the size, the Spider 2 is pretty similar to the NH-SPH above. It has a separate urine tank from the compost chamber and uses a 12 volt fan to boost its performance. What I like here is that the package also ships with a DC 12v adapter if you plan to use solar.

Similar to the NH-SPH, you could go up to 5 weeks before emptying the solid waste chamber- of course, depending on the number of users. Emptying is also relatively easier since the 2 chambers unlock in a matter of seconds.

[easyazon_link identifier=”B006TZ0O88″ locale=”US” tag=”toptoilets-20″]Check Price At Amazon[/easyazon_link]

6. Saniflo Saniaccess 2  – Most Comfortable Option

Easy Use By Everyone

Saniflo Saniaccess 2

Our last recommendation on this list is a 2 piece unit that is probably similar to what you have at home. You might want to go with this one if you don’t fancy the ‘weird’ design with the composting toilets and the emptying part.

2 Piece Design

It’s 2 piece design, however, means that it might occupy a little more space than the one piece Sanicompact 48 above. Again, unlike the composting toilets, this one requires some plumbing for its flush design.

Saniflo Saniaccess might be a good option, for instance, for a makeshift bathroom in the bathroom where it’s easy to access the waterlines but not the sewerage line.

That’s where its motor comes in handy, though. This means that you can install the toilet directly below the sewer lines without a problem.

Round Bowl and Standard Height

About comfort, the Saniflo Saniaccess has a round bowl and standard height for easy use by everyone. Previous users also confirm that it’s an excellent performer provided it’s professionally installed and maintained.

However, some also report that debris stick to the sides after #2. So, you might want to keep a Johnny mop or brush nearby.

[easyazon_link identifier=”B01G48AY4I” locale=”US” tag=”toptoilets-20″]Check Price At Amazon[/easyazon_link]

Editor’s Choice

[easyazon_image align=”center” identifier=”B009Z7EKIC” locale=”US” src=”https://images-na.ssl-images-amazon.com/images/I/41%2BwgRcwKbL._SL400.jpg” tag=”toptoilets-20″]

If I were to pick the best composting toilet system of the 6 in this list, that would be [easyazon_link identifier=”B009Z7EKIC” locale=”US” tag=”toptoilets-20″]Nature’s Head NH-SPH[/easyazon_link]. This model is compact and it’s self-contained design makes it a great option for RVs.

It takes up to 80 uses before the need of emptying, that’s about 5 weeks for 2 adults. Again, it does not require special treatment, and it’s also super portable.

Best Composting Toilet Comparison Chart

Rank:Model:Our Verdict:Price:Our Rating:Dimensions:Weight:Special Features:Shape:Color:VoltageWattageWarranty:
#1[easyazon_link identifier="B009Z7EKIC" locale="US" tag="toptoilets-20"]Nature's Head NH-SPH[/easyazon_link]Best Overall (Our Pick)$$$9/1022x20.5x21.7"28 poundsOdor Free Operation And Ease Of Disposal, All Stainless HardwareElongatedGranite12 volts0.72 watts5 Year Warranty
#2[easyazon_link identifier="B001CFQFL0" locale="US" tag="toptoilets-20"]Sun-Mar Excel Non-Electric[/easyazon_link]Premium$$$$$8/1036x36x28"90 poundsNon-Electric Model, Uses No Water, 100% Non-PollutingRoundWhiten/an/a5 Year Warranty
#3[easyazon_link identifier="B0014RQ8LI" locale="US" tag="toptoilets-20"]Saniflo 023 SaniCompact 48 [/easyazon_link]Budget$$8/1018.2x14.5x15.8"62.2 poundsEasy to Install, Quiet, AdjustableElongatedWhiteCheck With The ManufacturerCheck With The Manufacturer2 Year Warranty
#4[easyazon_link identifier="B003EX7LV6" locale="US" tag="toptoilets-20"]Nature†s Head NH1[/easyazon_link]$$$8/1019.8x20.8x20.5"27.2 poundsUser Friendly, Easy Installation, All Stainless HardwareElongatedWhite12 volts1 watt5 Year Warranty
#5[easyazon_link identifier="B006TZ0O88" locale="US" tag="toptoilets-20"]Nature's Head Spider 2[/easyazon_link]$$$8/1017.8x17.8x21.5"28 poundsEasy To Install, Absolutely No Odor, No MaintenanceRectangularGranite12 volts3 watts5 Year Warranty
#6[easyazon_link identifier="B01G48AY4I" locale="US" tag="toptoilets-20"]Saniflo Saniaccess 2[/easyazon_link]$$$8/10Check With The ManufacturerCheck With The ManufacturerPossible Connections: Toilet & Sink ONLYOvalWhite120 Vn/aCheck With The Manufacturer

Best Composting Toilet System Buying Guide

What Is A Composting Toilet?

Put in a layman’s language, a compost toilet is a toilet that does not need water for its operations. This is because these systems are not connected to a mains septic or sewerage line.

As you may have guessed, they have a chamber that holds your family’s waste for some time. On the same note, they require emptying after several uses. Stephen Henry, a Manager at Lehman’s Retail Store in Kidron, Ohio, explains, that a composting toilet is a highly engineered unit that uses biological processes to convert human waste into fertile soil.

Let’s discuss this in-depth.

How Does A Compost Toilet Work?

Now, there are different types of compost toilets- as you’ll find out below. However, regardless of their design, they all operate on the same principle of converting harmful human waste into organic compost material that is perfectly safe for use in the garden and other compatible areas.

Here is a basic flow chart of how a compost toilet works.

After using the toilet:

  1. Liquid waste is separated from solid waste and held in a removable container.
  2. A flush door opens allowing solid waste into the compost chamber.
  3. A seal automatically encloses the waste in the chamber.
  4. You turn the spider handle 3-4 times.
  5. An agitator bar inside the composting chamber mixes the solid waste with carbon material such as sphagnum peat moss, coconut fiber or sawdust. Aerobic bacteria work on the waste to avert all odors and to kill all harmful pathogens.

Types Of Composting Toilets

Composting toilet fall into 2 major categories:

Self-Contained

True to its name, a self-contained unit is a one piece that houses everything including the composting chamber. Oftentimes, the chamber is just below the toilet bowl. Due to their compact design, these models are ideal  for use in RVs, cabins, boats, and tight-space homes.

Central System

Also referred to as a remote system, a toilet with this design is pretty much similar to a conventional toilet since it directs the waste to a composting chamber located elsewhere. This may, for instance, be in the basement, garage, or even outside the building.

Other than the 2 categories that we’ve just talked about, composting toilets may also be classified according to how they operate as shown below:

Dry Composting Toilet

Also known as waterless toilets, these systems use almost no water. However, their performance is not affected by the small amount of water that you use for anal cleaning. Dry composting toilets use a narrow vent that runs out of the building to take air in and out of the chamber.

Electric Composting System

Basically, all composting toilet are dry system. However, electric waterless units use electricity to speed up the composting process. Usually, they have a fan that that ensures a continuous airflow through the vent.

This airflow creates a good environment for aerobic respiration by adding oxygen to the content. It also reduces the water content in the sludge besides eliminating odors.

Thanks to technology, several electric composting systems also employ heating elements. These components provide an optimal temperature range to keep the bacteria active.

Solar Composting Systems

Designed for situations where electricity is not available, these systems rely on solar energy to power up their small fans. Worth pointing out is that several electric composting units such as the Nature’ Head Spider 2 also come with a kit to convert them to solar power which, in my opinion, is a really good thing.

What Do You Look Out For In A Good Composting Toilet?

Let’s begin here, which category should you go for?

Your ideal category will depend on your needs. Central/remote system usually allows the installation of large composting chambers. As such, you may want to consider them if you want a larger unit for regular use at home.

On the other hand, self-contained commodes are usually easily portable and compact. They make great toilets for use in camps, RVs, boats, and cabins. Again, their compact design and small footprint also make them an ideal option for a small home.

When buying a composting toilet, you’ll need to consider its dimension and configuration (especially the spider handle) to ensure that it’ll fit in your bathroom.

You also need to plan for the ventilation shaft especially for a model that does not rely on electricity or solar power.

Without forgetting, it’s important to ask:

  • The number of users that the commode can serve.
  • Estimated maintenance intervals.
  • Energy and ventilation requirements.

How Do You Install A Composting Toilet?

The installation bit is usually fairly simple and straightforward. This is because unlike installing a flushing commode, there are no rough in measurements and complex sewerage systems to keep in mind.

This process involves bolting down the toilet to the floor. To make it even easier, most manufacturers include a detailed installation guide to take you through the entire process. There are also lots of how-to videos on YouTube that you could also rely on.

Among other things, the installation process might involve drilling a vent through the wall for the intake and exhaust lines. Depending on the model, you might also need to arrange for the electric or solar power supply.

Pros and Cons Of Composting

Pros

  • Does not involve complex sewerage systems and septic cisterns
  • Conserves water (they require little to no water)
  • Can be installed anywhere including areas where installing plumbing lines wouldn’t be possible
  • Involves minimal maintenance (but it’s critical)
  • Come in handy in emergency situations
  • Decomposed waste can be used to boost the soil’s fertility levels

Cons

  • It’s Expensive
    This is perhaps what holds most people from installing a waterless toilet. These units seem pretty expensive for what they are. However, the fact that these toilets have a 100% non-polluting and excellent water conservation design make these units relatively cheaper.
  • Could Be Smelly And Tricky To Empty
    According to Henry, the worst fear that most people have towards these models is SMELL. But, he continues to state that they are engineered not to emit any odors. However, this could change with lack of proper installation, usage, and maintenance.

How Much Does A Composting Toilet Cost On Average?

As I told you before, composting toilets have a relatively higher initial cost than a conventional flushing unit. The cost heavily relies on how basic or advanced the system is.

You should expect to part with between $600- $2500 for a basic toilet. At this price range, you may find both self-contained and central systems, electric and non-electric options.

Advanced composting systems cost upwards of $2500 and could go as high as 5 grand! At this range, however, you’ll be choosing between advanced self-contained models and high-capacity remote systems.

You’ll also find several electric models featuring heating elements to speed up the decomposition process. Some also boast sensors and vacuum flushing technology among other advanced features.

Composting Toilets – Just How Green Are They?

In its education outreach program, the government of Philadelphia notes that the average American family consumes up to 300 gallons of water each day. According to the US Environmental Protection Agency, the flushing toilet is the main source of water use around the house.

Despite the recent strict rules by most States to cap the modern toilet’s flush rate to utmost 1.6 GPF, these systems continue to flush a lot of fresh water down the drain. But the worst thing is that they don’t stop at that.

Most States require that the waste goes through a water treatment system before being released into waterways. This results in additional expenses that we could use on other projects.

According to the Chesapeake Bay Program alone, close to 1.5 billion gallons of water is collected from the nearby treatment zones. Although there are lots of effort to upgrade the water treatment facilities to minimize the harmful nutrients, most of the water in this Bay’s waterways is currently a threat to life.

What If We All Embraced The Composting Toilet System?

First, we’ll be able to save trillions of gallons of water that we use for flushing both solid and liquid waste.

Second, there would be minimal land degradation since there’ll be no need for complex sewerage and septic systems.

Third, we could save lots of energy that we have been using in transporting the waste for treatment and energy used in the treatment process itself.

Moreover, there would be minimal cases of pollution in our waterways. Even better, the humus (the end product of the decomposition process) can be used to boost the fertility of the soil.

Conclusion

Despite its relatively higher initial cost, the best composting toilet system is, as facts prove, the best way to curb the menace of water scarcity. These toilets are safe, hygienic, and above all else, water efficient.

Well, they may not be perfect for everyone. However, they always come in handy in circumstances where coming up with sewerage systems would be utterly uneconomical or impractical.

 

Dan is the editor in chief and founder of this site, after running into troubles with his own old toilet a while ago. Discussing toilets is not your everyday topic, so let’s talk toilets today.