Composting Toilet Reviews

In this review we compare composting toilets from what we believe to be the best manufacturers, each with their own unique design to human waste compost.

Sun-Mar Composting Toilets

Sun-Mar Composting Toilets

- Outdoor Composting Chamber
- Rotating Drum for faster composting
- Requires electricity for heater
- Widely available
- Many sizes

Avg. Price: $1,500 (and up)

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BioLet Composting Toilets

BioLet Composting Toilets

- Single Unit System
- Larger models require electricity for heating
- Trap doors

Avg. Price: $1,300 (and up)

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Clivus Multrum Systems

Clivus Multrum Systems

- Large system
- Waterless and Foam-flush designs
- Requires electric and water

Avg. Price: $10,000 ? Company does not list prices

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EcoTech Carousel Composting To

EcoTech Carousel Composting To

- Multi-chamber composting
- Separate composting chamber
- No heating element
- Ability to age compost up to two years

Avg. Price: $2,700 (and up)

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Envirolet Composting Toilets

Envirolet Composting Toilets

- FlushSmart Vacuum Flush
- No gravity required
- Modern, elegant design
- 10 persons per day for vacation use and 8 persons per day for continuous use. (Based on 3 uses per person per day.)

Avg. Price: $3,500 (and up)

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What research says

Composting toilets have come a long way in the last two decades. The first composting toilets were outhouses, at one time the ubiquitous outdoor bathrooms used by most western families. These days having a composting toilet is growing in popularity among off-grid home owners and seeking to reduce their burden on the environment by eliminating what they believe to be the unnecessary step of waste treatment plants and sewerage. By incorporating battery-back-up solar power, solar and tankless hot water heating, passive solar, graywater and toilet composting in the design of a home one can live in total comfort without being bound to the public water, sewerage or electric system.

Here are some of the best composting toilet systems around, each with their own modern-day twist on an age-old concept:

Sun-Mar Composting Toilets
Sun-Mar is probably the best-known composting toilet maker in all of North America. Their design puts the toilet unit inside the bathroom with the composting chamber and ventilation pipe sitting outside of the house. Another unique part of the Sun-Mar system is the composting chamber, which rotates like a clothes dryer. This allows oxygen to get to all of the contents, thus keeping the compost aerobic, which speeds up the rate of decomposition. Like most composting toilets, there is a separate chamber called the "finishing drawer" where the aged compost sits awaiting removal. Some online reviews claim that sometimes fresh waste falls into the finishing drawer in Sun-Mar composting toilets, which results in finished compost that may still contain pathogens and retain an odor. However, due to the design of their system (the drum only turns one way) I don't see how that could be possible. Furthermore, Sun-Mar systems are certified by the National Sanitation Foundation International, which requires finished compost from toilets to contain less than 200mpn/gm of orderless fecal matter.

BioLet Composting Toilets
BioLet makes an interesting composting toilet. It differs from others in several ways, such as requiring an electric source for heating and evaporating the liquid and a set of "trap doors" that automatically open when you sit on the toilet. For women, this might sound like a great idea. Who wants to look down at the "compost" after all? But for guys - who don't sit down to pee - it might take some creative foot placement to apply enough pressure on the seat for the trap doors to open. BioLet composting toilet designs are compact and put the composting chamber inside the house, directly under the toilet in a "bucket-like" design. They do have a tendency to over-dry the compost, which makes it difficult sometimes to stir the compost (which is necessary to prevent anaerobic conditions) using the externally-accessible stirring rods.

Clivus Multrum Composting Toilet
The Clivus Multrum composting toilets require a large accessible space below the toilet itself, typically located in the basement in a house, or under a raised platform in parks and other recreational areas. Their waterless design (they also have a foam flush) relies on gravity to move the "compost" down a ramp. It includes an automatic moistening system, which requires the system to be connected to a water supply, even those it is a "waterless flush" design. It also has to be connected to power in order for the liquid removal system to work, which removes liquid from the main chamber of the composter and sends it to a separate storage tank. Due to the size, complexity and cost of this system it is not on the top of our list in this review. But that is only because this review is focused on home-use toilets.

EcoTech Carousel Composting Toilet
EcoTech toilets are made for full-time use for entire families, as opposed to some of the smaller designs like many of the Sun-Mar and BioLet models, which are designed for cabin and vacation home use. This design is multi-chamber (usually four) and should be rotated when full, which takes from two to six months. This means one "batch" of composting material can age for up to two years. It also means no "fresh" material can mix with the older material, thus ensuring that more pathogens are destroyed and you get a cleaner end-product. The EcoTech composting toilet system is usually set up with the composting chamber in the basement and a ventilation pipe running up from the chamber through the roof or wall of the house.

Envirolet Composting Toilet
The Envirolet composting toilets are a last-minute addition to this review / comparison, but are definitely worth looking into. They are good looking units that are designed at different sizes and prices depending on your needs, but all of them have the first Vacuum Flush technology we've seen in a composting toilet. This allows you to install an Envirolet unit for full-time use in a home that does not have a basement by putting the storage tanks in an adjacent room (as seen in this image).

All of these composting toilets are high-quality systems by trusted manufacturers. Although it is a tough choice, in the end we would recommend a different system for three different needs and price ranges:

  • Best for industrial and municipal use: Clivus Multrum
  • Best for small family (3-4 people), Cabin or Vacation Home Use: BioLet or Sun-Mar
  • Best for large family continuous use (with basement): EcoTech
  • Best for family continuous use (no basement): Envirolet

Average Rating

Composting Toilet Reviews
Average Rating: 4 out of 5 based on 5 ratings.

cread said:

Biolet NE (non-electric) is NOT as advertised. It's smelly, buggy and high maintenance, even with fan. I am now trying the Sunmar, hoping for better results. Going green can be an expensive disappointment.

susan heino said:

What about the envirolet composting toilet? They have ads on this page and have been is use for 15 plus years?

Dan said:

I have a Biolet 20 Deluxe. It does not work.
The fan is loud. The construction feels cheap.
It leaked fluid onto the floor, and I had to empty it twice in 7 weeks with 2 people full-time. We no longer pee in it, as it could not come close to handling the liquid load of 2 people.
It uses far too much power for off-grid applications.
Completely disappointed and frustrated with the whole situation.
Take your $1900 and build an outhouse.

Gene said:

There are a lot of complaints about Biolet and Envirolet if you look around at enough websites. Be careful; they're expensive. Also not mentioned here are Nature's Head at $850 which seems to get good reviews, plus a kit for $115 that enables you to build your own. The Separett designs seem to make the most sense; they have separate containers for urine and feces. It eliminates a lot of odors--and dealing with wet sewerage.

Charles Ramsburg said:

The Biolet 30 NE is a real stinker. The urine does not drain because the drain hole is way above the bottom. It also will not work below 64 degrees, great if you live in the Southern parts. My old outhouse is much better and a heck of alot cheaper. PeeU, C. Ramsburg

Ovid Need said:

How do we request a catalog on the various models?

Becky said:

I have a biolet 20 deluxe too.... the electric type.. yes the fan is loud.. I got used to it.. the bathroom is next to my bedroom so yes its loud.. then toilet paper would get sucked into the fan and it would stop... it has done this about 5 times ! we have had to take the whole thing outside in the middle of winter and take it apart to get the paper out! and replace the fan motor.. ( it was covered by the company but you get reimbursed after you send the old one back and its 50 bucks!) I was told by the company that yes this happens.. and I should use a spray bottle and wet the toilet paper after I use it..ok I did that but the fan just drys it again! so if its not buried right away.. it will collect around the rod that turns the bottom paddles that move the compost and will twist up the pipe into the fan.. so I was always pulling the paper off the pole.. have to stick your hand in there to do that! and yes I sue the right kind of paper.. at about $3.85 a pack of 4! then I started to just throw away all toilet paper in the garbage can for pee wiping( this way I can sue cheaper regular stuff and save money) and only leave paper in when I wiped my butt .. it still happens., even if I spray the paper which I do.... its not working now again and Im just furious! it also has problems with fluids.. they seem to collect so when you clean it you get alot of really smelly sludge in the tray! and it does smell even with the fan and all... not alot but if it gets cold out then it gets worse! I live alone and am careful with it.. I make sure to put the right amount of compost dirt in it.. the kind that comes with it.. also the the part that opens when you sit on it so you dont have to look at the crap...the little doors..... well that feel apart before Id had it year. the nuts came undone from the part that holds it on and they fell into the toilet.. I called hte comany and they said..yes this ahppens alot too! and to make sure the whole harness part insnt in there as it will clog up everything.. thank god it wasnt.. so when we took it aprt to clean it and replace the fan motor we took the whole thing off... I can live without that but the fan.. they need to make a door you can open to remove anything that gets sucked up in the fan or.. put a screen or something in pace so it doesn't happen! Im not happy at all... now i have to leave it unplugged and only plug it in to turn it after I use it. until I fell up to the task of taking it apart again.. sigh

La Fekken said:

Oh if i could afford one of these, i would!
Our Grand Traverse Construction Code will allow a composting toilet in your home if it is in a secondary bathroom.
Water is becoming scarce and these toilets should be the NORM and NOT the exception!

marina said:

Enviorlet composting toilets with the composting unit in the bottom which is inside the house is crap (no pun intended) It does not get rid of the pee and the compost is allways wet. I have had to remove the wet compost myself and it seems to me it is like collecting your crap. I have seen other composting toilets that work better and I believe Sun Mar has a good one with a big rotating drum.

Tex said:

I have a Biolet NE in my cabin where I live full-time and it has never worked as advertised. The Biolet NE has all of the problems mentioned by previous posters and I would not buy one again.

John said:

Biolet is a nightmare. They stink and don't work as advertised. I've seen the same responses and excuses in every case I've read. I had over $2000.00 invested in my Biolet 60XL system. NEVER AGAIN! Biolet and Home Depot are both thieves!

Dan said:

What about the Phoenix composting toilet. It has not been reviewed.

lloyd said:

our employer installed a Biolet 60XL, we have 4 people using in 24 hrs. NOT RECOMMENDED AT ANY PUBLIC SERVICE WORKSITE.... Unit does not work, tray over fills with fecal matter, with in 7 days, NOT allowed to put toilet paper in it because it plugs it up. THE SMELL OF RAW FECAL MATTER from unit and vent is present indoors and on the ground outdoors......THESE UNITS ARE INHUMANE AT A PUBLIC SERVICE WORKPLACE!!!! BOUYCOT THESE UNITS....there is no composting done.... disposing disseased raw fecal matter from units....

Joy said:

Does anyone know how good biolan naturum composting toilets are?

Brent said:

This site is missing one of the best composting toilets on the market which is the PHOENIX composting toilet made by Advanced Composting Systems

Jon said:

Envirolet power models consume 500 watts. This is a serious power draw. I chose a non-electric Envirolet and it did not completely evaporate the liquids, leaving a stinking mess not compost.

Hippy Dad said:

For a cheap and effective composting toilet, nothing beats a 5-gallon bucket and some sawdust.

rick said:

if you like to vacum the urine every 2 weeks and don't mind the small flies coming out the compost drum at every use,,,,,,,,,,,,,,,,,it is a great unit.. in truth the most discusting purchase we ever made. can not even hire anyone to vacume urine from lower unit and clean out waste. I am disabled and can no longer do the a/m/

e melanson said:

i have had a sunmar centrax 2000 for 10 years actually 2. the first one had the drum colapse from the housingas the fiberglass buldged.sunmar shipped a new unit to me free of charge. when i installed the new unit i framed it in to eliminate this problem.unfortunately the unit never worked to my satisfaction after an exspenditure of 3000 dollars.the unit always stunk. ifollowed all instructios yet the peudo compost was always wet.if you think you can move excretment and toilet paper approximately 12 feet horizontally with the correct angle with one cup of water forget it.even now with a near vertical angle it does not work to my satisfaction, to the point i will be installing an inground septic far as being enviromentally friending in my opinion it is no better than an outhouse.i would NOT put any materials taken from my unit into my my opinion it will finally be correctly installed when i put it in the local landfill. thank you for allowing me to vent

Perry said:

My Sun Mar Excel's heater stopped working, and now
I do have a problem. Bad feature.

Mark said:

Please let people know that the Biolet products DO NOT WORK! I own two and they do not work even close to how they are advertised. Heavy urine smell, horrible service from a bitchy rep who is not helpful. Being told to hire an electrician is not helpful after the 3rd time my toilets have broken down in 6 months. I can see from your comments that I'm not the only one having this problem. They are expensive to operate and need to be dumped/cleaned at least monthly even under low usage. They cannot handle toilet paper and clog the fan constantly. Save your money!

Peter said:

Envirolet disaster! I live in the tropics of North West Australia. Purchased a Envirolet waterless self contained 12 volt unit. Have now used many recipes for mixture, even recommended mixture by supplier, still a mud mixture, and thats in the tropics. Both fans have failed and top rake broke, all under 6 months. Although parts have been warranty replaced, I suggest to everyone not to waste your hard earnt money on a Envirolet product

Peter said:

Hi have an enduring experience of purchasing a waterless envirolet compost toilet and it has been nothing but useless! Besides the 12v fans failing on average, every 6 months and the raker bar breaking around the same time, I believe the design is a total failure. I have had pre support from the Australian supplier to fine tune the mixture, and yet the front section can stay quite damp due to urine and the rear of the unit dries to a hard clump as the rake bar does only a forward and back movement so anything else just stays put.The after sales support is nearly absent, takes about 3 months each time with constant email badgering to get warranty parts delivered. Going by the Australian suppliers removal of his phone contact, I say he has pulled out of Envirolet, can't blame him

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