April 28

Composting Toilets for RVs and Tiny Homes



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Composting toilets are one of the best flush toilet alternatives in the market, especially if you live in a tiny home, use an RV, or you just want to be more eco-friendly and save water. These toilets don’t rely on plumbing or sewage systems, and on running water to operate.

Composting toilets can save you a lot of water, depending on your usage. According to research, an average household uses 1/3 of total water consumption a day just by flushing.

Separett composting toilet tiny bathroom minimalist
Separett Composting Toilet

For RV users, a typical 100-gallon water tank, with 2 persons, can last around a week. This can be a problem if you are on the road traveling without access to freshwater.

Under normal home settings, the same research found that an average person consumes 550 gallons per month.

Apart from the water you can save, it is also beneficial for the environment as it can help with water management and reduces toxins mixed with the water system.

If you are looking about installing composting toilets in your RV or tiny homes, read along.

What is a Composting Toilet and how does it work?

Composting toilet is a toilet system where human wastes are disposed of “manually”, turning into compost-ready material, rather than the traditional waste management system.

A compost toilet has 2 parts: a place where you sit, and a composting unit comprising:

  1. the composting chamber or waste cabin
  2. a ventilation system for moisture management and venting-out odorous gases, and
  3. an extraction door

Single vs. Multi-Chamber

There are 2 kinds of Composting toilets: Single chamber and multi-chamber toilets. Each has its own pros and cons.

  1. Single chamber composting toilet only has 1 chamber for solid and liquid human waste. It is similar to the traditional toilet installed in regular homes.
  2. Multi-chamber toilet has 2 storage chambers to separate solid and liquid waste. Manufacturers of multi-chamber toilets emphasize the need to keep these 2 wastes separate to avoid bad smell or odor from building up. To do this, there is a separate hole where to dispose solid waste, and another hole for storing your urine.

You may need to purchase compost medium, depending on the brand of composting toilet you will use. The most popular compost mediums are the following:

  • Saw dust – cheapest alternative
  • Coconut coir – easier to store; best for small spaces; needs to be hydrated prior to use
  • peat moss – larger container, similar to soil.

These 3 have the same purpose and works in a similar way. People usually prefer peat moss because this is cheaper than coconut coir.

Composting – Chemical Process

In composting toilets, human wastes are aerated to give way to aerobic microbes to kill pathogens and convert waste into compost material that’s ready for 2nd compost. There are several microbes that can turn your waste into composts, it all depends on the temperature.

You have psychrophilic microbes which decompose waste and thrive at a temperature ranging from -20 to +10C. Then we have the more common mesophilic microbes that thrive at +20 to +40C. We also have the Thermophilic microbes that live in temperature ranging from 41-60C.

When doing composts, note that parasites and parasite eggs found in human wastes can only be killed under thermophilic environments. Therefore, Incinerating toilets may be better in such instances. however, note that incinerating toilets’ end product is ash-like rather than soil compost., and will require electricity.

Another note is that waste-derived composts recycle fecal nutrients but can carry and spread pathogens if composting is not done properly. Pathogen destruction in composting toilets is usually low. This carries the risk of spreading disease.

Benefits of Composting Toilet vs. Traditional Flush Toilet System

Apart from the amount of water you will save from flushing, here are some of the added benefits of using a composting toilet:

  1. No sewage – Sewage is just water, urine, and fecal matter combined into one big sludge. Not only is it unhygienic, but is also very difficult to handle especially during dumping.
  2. No need for the black tanks (in RVs and tiny homes with wheels) or septic tanks (for park models).
  3. Easy installation – since you won’t be needing to have a black tank, septic tank, or create a sewer line.
  4. Lesser odor – since you won’t be needing a black tank, septic tank, or a sewer line, there isn’t any risk of sewage odor.
  5. Longer camping time by extending your water reserves.
Nature's Head Composting Toilet tiny bathroom
Nature’s Head Composting Toilet

Best Composting toilets in the market

As mentioned, there are 2 kinds of composting toilets, single and multi-chamber toilets. In this section, we will discuss the most popular composting toilets for RV and tiny homes

Before going to the comparison, it is worthy to note that since the multi-chamber toilets require that liquid and solid should be separate, men are required to urinate sitting down to ensure that nothing falls to the solids bin.

Nature’s Head – https://natureshead.net/ – $925

One of the most common and popular in the market, Nature’s head is a self-contained multi-chamber composting toilet that uses compost medium for better moisture management.

The official site says the capacity of the urine bottle is 2.2 Gallons, and the solid waste compost bin is good for 60-80 uses. However, most users say that they were able to fill the waste cabin in about 4-5 days before dumping.

Nature's Head Composting toilet


  • Cheaper than other alternatives
  • Easier to install with just 2 brackets on either side to keep it in place
  • In case of overspill in urine, catchbasin ensures urine will not spill on the floor.


  • Need larger space because of how it opens; not suitable to be installed against the wall.
  • When disposing of urine, you have to open the whole compost bin, thereby exposing your solid compost chamber
  • Need to purchase separate lid to cover solid waste bin ($20.00)
  • The urine container is semi-opaque. Therefore, if you wish to dispose of your urine, it won’t be as discreet. This should also be considered especially when you have females as mentrual blood may be present.
  • Composting is dependent on the temperature. It will not fully compost in super cold or very humid weather

Air Head Composting Toilet – https://airheadtoilet.com/ – $1,029

Air Head Composting Toilet is similar to Nature’s Head where it separates solid and liquid wastes and it requires compost medium. They also work the same way. Choosing Air Head over Nature’s head will just be a matter of preference.

Capacity is the same with Nature’s Head, with the official site stating that it is good for 60-80 uses.

Air Head Composting Toilet


  • Urine chamber is separate from the solid waste. therefore, when disposing of urine, you don’t need to open the toilet and see solid waste
  • Urine container is Opaque. This makes it discreet when emptying out the urine bottle.
  • Shaped like a toilet seat with rubber gaskets to avoid the odor from leaking out.
  • Comes with a free lid to cover your solid waste bin in time of dumping.
  • Smaller than other composting toilet competitors


  • Composting is dependent on the temperature. It will not fully compost in super cold or very humid weather
  • the “flush” lever and compost lever is on different sides. It does not matter to some, but when space is tight, you are forced to have the toilet center with equal spacing for your hands to pull the lever.
  • Expensive than its competitors
  • More brackets and screws for securing it in place.

Sun-Mar Composting Toilets – https://usa.sun-mar.com/ – starts at $1,695

Having been in the business since the 1980s, Sun-mar has established its reputation for its reliability. It has, unlike the composting toilets mentioned above, its self-contained models do not have separate container for solid and liquid wastes. Instead, it has a 3 chamber system where:

  • 1st chamber to collect all kinds of waste, then excess liquid will drain to the 2nd chamber
  • 2nd chamber where excess liquids are evaporated, leaving the compost dry
  • 3rd chamber where the compost is extracted.

The Sun-Mar Advantage

Sun-Mar 3-Chamber Technology composting toilet for tiny homes
Image from USA Sun-Mar

Sun-Mar’s offers a wide variety depending on your need. They have Electric and Non-Electric variants and High and Medium Capacities. See more options here


  • No learning curve/ long time getting used to since there is no need to separate solid from liquid wastes
  • Easier dumping since remaining dry waste is extracted from the finishing drawer.
  • Many models to choose from


  • Takes up much space
  • Expensive
  • To ensure composting works properly, you may need to purchase additional medium sold on their website

Separett – EUR583.20

Separett is different from the composting toilets mentioned above where this one does not use any composting medium. Instead, it diverts your liquid waste into a separate container, and the solid waste to the main bin, aerate it to avoid/reduce the odor and dispose of the solid waste as you would with any other regular compost waste using their compostable garbage bags.

Unlike its competitors, Separett don’t requre you to use compost medium. Therefore, your solid waste will remain as is, and will be disposed using a compost bag for proper composting.


  • no need to purchase compost medium
  • urine can be drained either through the regular sewer line, through a urine pit (to be disposed separately), or whatever system you have at home.
  • easier to dispose of solid waste as you don’t have to carry the whole toilet out – same as disposing regular garbage bags.


  • your solid waste is visible, especially when disposing
  • more applicable to tiny or stationary homes,
  • will require bigger space

Which one is for you?

These composting toilets have different features which make them suitable depending on your need. No matter which model or type you use, the benefits are the same, It really boils down to preference and lifestyle.

We at TruForm Tiny can help you. These toilets are great for your tiny homes and RVs. Let us know what you want and we will customize the space for you.

About the author 

Jen Carroll

Jen is one of the founders and has specialized in tiny home production. At times he breaks away and contributes to the conversations about tiny homes. When not building tiny homes Jen is enjoying his kids trying to keep up with the endless creativity and boundless energy.

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