How Do Composting Toilets Work in Tiny Homes: An Efficient Solution Explained

If you buy through links on our site, we may earn an affiliate commission. Details
How do Composting Toilets Work in Tiny Homes
How do Composting Toilets Work in Tiny Homes?

As more people opt for minimalist living in tiny homes, composting toilets have gained popularity as an eco-friendly and efficient solution to address waste concerns. These toilets have been designed to optimize limited space while providing an effective way to manage both liquid and solid wastes independently. By separating urine and feces, composting toilets create an environment that supports the decomposition process, ultimately transforming human waste into a nutrient-rich fertilizer.

Understanding the composting process in tiny home toilets is essential for deciding if this toilet is the right option for your needs. The composting process primarily relies on dehydration and aeration through a urine-diverting system that keeps liquids apart from solids. This ensures minimal odor and accelerates the decomposition of solid waste, enabled by the presence of peat moss or wood chips to enhance the process. By becoming familiar with the inner workings of composting toilets, one can appreciate their benefits and challenges, as well as make an informed decision about incorporating one into a tiny home.

Key Takeaways

  • Composting toilets are a popular solution for waste management in tiny homes, separating liquid and solid waste effectively.
  • The composting process relies on dehydration and aeration, aided by a urine-diverting system and the addition of materials like peat moss or wood chips.
  • Understanding the basics of composting toilets helps homeowners appreciate their advantages and challenges, ultimately informing their decision to install one in their tiny home.

Basics of Composting Toilets

Composting toilets are an environmentally friendly and sustainable alternative to traditional flush toilets. They break down human waste by using aerobic decomposition instead of flushing it away with water, making them an excellent option for tiny homes.

Composting Toilet Components

A composting toilet typically consists of two main components: the compost chamber and the aeration unit. The compost chamber is where the waste is collected and combined with compost material, such as peat moss or sawdust, to start the decomposition process. The aeration unit, also known as the evaporation chamber, enables proper air circulation, which aids in odor control and promotes faster waste decomposition.

Self-Contained System

The self-contained composting toilet is the most popular choice for tiny homes and RV owners. It includes detachable bins for liquid and solid waste, which have to be manually emptied. The self-contained system often incorporates a fan in the aeration unit to help evaporate liquid waste and control odor. Since this type of composting toilet does not require any connection to a sewer or septic system, it is both cost-effective and low-maintenance.

Central System

The central system, or bi-level system, features a toilet located on the bathroom floor and a composter situated beneath it, often outside the living space. Central systems typically use gravity or a pump to transport waste from the toilet to the composting chamber. The processed solid waste is more voluminous, and therefore may require more frequent emptying compared to a self-contained system. However, this setup allows for a larger composting chamber, making it suitable for high-usage scenarios.

Central System Composting Toilet
Central System Composting Toilet

Composting toilets are safe, water-saving, and low-maintenance alternatives to traditional flush toilets. They also contribute to a more sustainable and eco-friendly living solution, especially in tiny homes where resources are often limited. By understanding the basics of composting toilets and the different configurations available, homeowners can make informed decisions about the best waste management system for their unique needs.

Installation in Tiny Homes

Space Considerations

When installing a composting toilet in a tiny home, it’s important to consider the available space. Most composting toilets are compact and designed to fit in smaller spaces, but each model varies in size and shape. Measure the area where you plan to install the toilet and make sure there’s adequate clearance for seating, access, and cleaning. Think about convenience, privacy, and overall aesthetics when choosing a location for your composting toilet in your tiny house.

How do Composting Toilets Work in TIny Homes?
Composting toilets are compact and can fit inside your tiny home.

Venting Needs

Proper ventilation is essential to ensure that your composting toilet functions efficiently and minimizes unpleasant odors. A well-installed venting system allows air to flow in and around the toilet, speeding up the composting process and keeping the space fresh. Venting can be achieved through several methods, such as installing a vent pipe that leads outside the tiny home, using a fan to circulate the air, or incorporating a window or vent in the bathroom wall. Whichever method you choose, make sure it provides adequate airflow and adheres to any applicable building codes.

Off-Grid Living

For off-grid living enthusiasts and tiny homeowners who want to reduce their ecological footprint, composting toilets are a perfect solution. They don’t require water or electricity to function and produce nutrient-rich compost, which can be used in gardens or landscaping. Since these toilets don’t rely on traditional plumbing or sewage systems, tiny homeowners can avoid the costs associated with septic tanks or sewer connections. Additionally, composting toilets are an excellent choice for locations without access to water or electricity, making them suitable for even the most remote tiny homes.

Composting Process and Materials

Composting toilets work in tiny homes by facilitating the natural decomposition of human waste through the use of microbial activity and proper ventilation. This process converts the waste into nutrient-rich compost, which can be safely used in gardens or landscaping, while minimizing water usage and providing an eco-friendly waste management solution.

Organic Materials

In a composting toilet, organic materials such as peat moss, sawdust, grass clippings, leaves, and coconut coir are used as bulking agents to help absorb moisture, retain air pockets, and create a suitable environment for microbial activity. These materials can be mixed in with the waste to support proper composting.

  • Peat moss: Absorbs excess moisture and provides an acidic, low-nutrient environment to deter harmful bacteria growth.
  • Sawdust: Absorbs moisture and adds carbon to the mix, balancing out the nitrogen in human waste.
  • Grass clippings and leaves: Provide carbon while decomposing at a slower rate, allowing for aeration in the compost.
  • Coconut coir: Retains moisture and provides a neutral pH environment, promoting aerobic decomposition.

Moisture Level

Maintaining an appropriate moisture level in the composting toilet is crucial for the efficient breakdown of waste. Too wet or too dry conditions can hinder the process, as the microorganisms require a certain amount of moisture to survive and function effectively. Aim for a damp, but not overly wet, consistency in the compost. This can be achieved by:

  1. Regularly adding bulking agents like peat moss or sawdust
  2. Ensuring proper ventilation to allow excess moisture to evaporate
  3. Monitoring the compost’s appearance and adjusting the moisture levels accordingly


Bacteria and other microorganisms play a vital role in breaking down organic materials within the composting toilet. These microbes digest the waste and convert it into a stable, nutrient-rich compost known as humus. By creating a hospitable environment for these microorganisms, you can ensure successful decomposition of waste in tiny homes:

  • Fresh waste is high in nitrogen; balance the carbon-to-nitrogen ratio by adding carbon-rich materials like sawdust or leaves.
  • Maintain suitable moisture levels to support bacterial growth – not too wet or dry.
  • Regularly aerate the compost by stirring or turning it to promote oxygen flow and aerobic decomposition.
  • Use commercial microbial additives, if needed, to jumpstart the process or re-establish microbial populations after cleaning the system.

Maintenance and Operation

Managing Liquid Waste

In a composting toilet, liquid waste is typically separated from solid waste. The liquid waste is diverted into a separate container or piped out to an external receptacle. It is essential to regularly empty the liquid waste container to prevent overflow and ensure the smooth operation of the system.

Managing Solid Waste

The solid waste in a composting toilet is broken down by microbes in the presence of oxygen. To enhance decomposition, it is vital to maintain the right balance of carbon and nitrogen materials inside the waste chamber. Regularly adding carbon-rich materials such as sawdust or coconut coir helps prevent excessive moisture, which can affect the decomposition process. Over time, the solid waste turns into nutrient-rich compost that can be used for gardening or landscaping purposes.

Temperature Control

Temperature plays a crucial role in the efficiency of a composting toilet. An optimal temperature range for the decomposition process is between 40°F and 140°F. It is essential to monitor the temperature within the composting unit to ensure efficient breakdown of waste. A well-insulated unit can help maintain the appropriate temperature level. In colder environments, a heating element or extra insulation may be necessary.

Odor Control

A well-functioning composting toilet should be odorless due to a proper ventilation system. The system typically consists of a fan and vent pipe, which work to eliminate any unpleasant smells by expelling them via vents to the outdoors. Ventilation also helps regulate moisture levels inside the waste system, improving the decomposition process. Regular maintenance of the ventilation system, along with proper waste management, is key to maintaining an odor-free and efficient composting toilet in a tiny home.

Legality and Regulations

Composting toilets are an eco-friendly and convenient waste management solution for tiny homes. However, it is crucial to know about the legality and regulations governing their use.

In the United States, composting toilet regulations differ from one municipality to another. Some states, like North Carolina, don’t have any codes for composting toilets at all. In other locations, composting toilet codes may not apply to homes that already have a flush commode in place.

When considering the installation of a composting toilet, it is essential to research the specific regulations that apply to your state or local municipality. This will ensure that your tiny home is in compliance with local building codes and environmental guidelines. It is also important to consider any possible legal concerns when traveling through different states with a tiny home equipped with a composting toilet.

To help navigate the legality surrounding composting toilets, several states have adopted regulations that specify the conditions under which these eco-friendly waste management systems are allowed. As of now, 27 states in the US have made provisions for composting toilets to be considered legal.

Keep in mind that regulations may change over time, and it is essential to stay up-to-date with the latest information on composting toilet rules and guidelines in your area. If you are traveling through different states with your tiny home, be prepared to research and comply with the local regulations in each place.

Remember, it is vital to ensure compliance with the regulations surrounding composting toilets in tiny homes. Consulting with local authorities, or using the resources available online, can help you better understand the legality and guidelines in your specific location.

Advantages and Disadvantages

Composting toilets are becoming increasingly popular in tiny homes due to their sustainable nature and low environmental impact. In this section, we will discuss the advantages and disadvantages of using composting toilets in tiny homes.

One major advantage of composting toilets is that they save freshwater resources. Traditional flush toilets use a significant amount of water, whereas composting toilets use none. This is especially important in tiny homes where freshwater storage can be limited. Additionally, the end product of composting toilets is usable compost, which can be used as fertilizer in a garden composter or spread around plants.

The costs associated with composting toilets can be both an advantage and a disadvantage. Installing a composting toilet can be cheaper than installing a traditional septic system, as there is no need for a septic tank or complex plumbing. However, composting toilets themselves can be more expensive than regular toilets, but this cost may be offset by the reduced need for septic system maintenance and freshwater usage.

A potential disadvantage is the need for proper management of the composting process. To ensure the compost is safe to use as fertilizer, it must be properly maintained in a regular garden composter. This means monitoring temperature, oxygen levels, and moisture content. A poorly managed composting process can produce foul odors and make the end product unsuitable as fertilizer.

Overall, composting toilets offer several benefits, including water savings, usable compost, and potentially lower installation costs compared to traditional systems. However, proper management is crucial to avoid odors and maintain compost quality. Ultimately, residents of tiny homes should weigh the pros and cons to decide if composting toilets are the right choice for their needs.

Alternative Toilet Options for Tiny Homes

When considering toilet options for a tiny home, a composting toilet is not the only choice available. There are other alternatives that work well in tiny homes and RVs due to their comparable design features and functionalities.

Incinerating toilets are an environmentally-friendly option that requires no water or sewage connection. They utilize propane or electricity to burn waste at high temperatures, reducing them to small amounts of clean ash. This toilet type is efficient in small spaces like tiny homes and RVs, but its downside includes a higher energy consumption.

Dry-flush toilets are another alternative option. These toilets have a unique cartridge system that wraps and seals waste in a biodegradable film after each use. They are waterless, easy to install, and portable, which makes them suitable for tiny homes and mobile settings. However, the cartridges must be frequently replaced, potentially leading to higher ongoing costs.

In case a person is dealing with diarrhea, care must be taken while using alternative toilet systems, as liquid waste may compromise the efficiency of some of these options. For instance, composting toilets usually come with separate chambers for solid and liquid waste. Therefore, it’s essential to maintain a balance in the contents of each chamber for the system to work efficiently.

No matter the choice of alternative toilet options, it’s crucial to remain confident and knowledgeable in their operation. By maintaining a clear understanding of tiny house toilet options, owners can ensure their living experience remains comfortable and eco-friendly.

Do-It-Yourself Composting Toilets

Composting toilets are a sustainable and eco-friendly solution for waste management, especially in tiny homes where space and resources are limited. In this section, we will discuss how you can build your own composting toilet system for your tiny house, focusing specifically on the process of humanure management.

Building Your Own System

To build a DIY composting toilet, you will need the following materials:

  • A sturdy container to serve as the base of the toilet (e.g., a 5-gallon bucket)
  • A tight-fitting lid or seat for the container
  • Sawdust, peat moss, or coconut coir for covering and absorbing waste
  • A separate container for collecting urine (optional, but recommended for better odor control)

Here’s a step-by-step guide to building your DIY composting toilet:

  1. Prepare the base and seat: Place your 5-gallon bucket in a designated area within your tiny house. Make sure it is easily accessible and well-ventilated. Attach a tight-fitting lid or toilet seat to the top of the bucket to keep odors contained.
  2. Divert urine (optional): If you prefer, add a urine-diverting system to separate urine from solid waste. This could be a funnel connected to a hose that leads to a separate container or an integrated diverter on the seat.
  3. Add a base layer: Before using the toilet, add a 2-inch layer of sawdust, peat moss, or coconut coir to the bottom of the bucket. This material will help absorb moisture and mask odors.
  4. Use and maintain: After each use, thoroughly cover the waste with another layer of sawdust, peat moss, or coconut coir. This reduces odors and contributes to the composting process. Empty the urine container regularly to prevent overflow and strong smells.

When your waste container is full, transfer the contents to an outdoor composting bin, where it will continue to decompose into nutrient-rich compost. Here are some guidelines to follow when managing your outdoor compost pile:

  • Use two separate compost bins: one for fresh waste and one for decomposing waste.
  • Make sure your compost bins are well-ventilated, as aerobic bacteria help break down the humanure.
  • Regularly turn the contents of the compost bin to help mix the material and promote aeration.
  • Let the humanure compost for at least a year to ensure its safety before using it as garden fertilizer, especially for non-edible plants or fruit and nut trees.

By following these steps, you can create your own do-it-yourself composting toilet system for your tiny home, effectively managing waste while contributing to a sustainable and eco-friendly lifestyle.

Common Myths and Misconceptions

There are several myths and misconceptions surrounding the use of composting toilets in tiny homes. To provide a clear understanding, let’s debunk some of these misconceptions.

Firstly, many people believe composting toilets are unsanitary, due to the presence of pathogens in human waste. However, when maintained correctly, composting toilets are safe and effective. Bacteria, fungi, and other microorganisms break down the waste, killing pathogens and rendering it harmless in the process. The end product is nutrient-rich compost that can be safely used for gardening or landscaping.

Another common myth is that composting toilets produce unpleasant odors. This misconception stems from comparing them to traditional toilets or outhouses. In reality, composting toilets can be virtually odor-free when properly ventilated and maintained. Proper aeration prevents any build-up of unpleasant smells and allows the decomposition process to continue without any issues.

Some people may think that composting toilets are only suitable for rural or remote locations, but this is not the case. In fact, composting toilets can be a space-saving and eco-friendly alternative to traditional flush toilets, which makes them ideal for use in tiny homes in urban areas as well. Composting toilets are also effective regardless of the climate, whether it’s hot, cold, or temperate.

A common misconception is that composting toilets are difficult to maintain and require frequent emptying. However, depending on the design and usage, many composting toilets only need to be emptied every few months or even once a year. Moreover, composting toilets with central systems can handle multiple users, making them suitable for shared tiny home communities or larger households.

Finally, some individuals might assume that composting toilets are an expensive and less efficient option compared to traditional toilets. While the upfront costs of a composting toilet might be higher than a conventional flush toilet, the long-term savings in water usage, wastewater treatment, and the production of compost can outweigh the initial investment.

Video – How do Composting Toilets Work in Tiny Homes?

An excellent video guide to composting toilets in tiny houses.

Composting Toilets in Tiny Homes


In conclusion, it’s essential to discard any myths and misconceptions about composting toilets, especially when considering them for use in tiny homes. By being knowledgeable and confident about their benefits and functionalities, homeowners can make informed decisions for a more sustainable and eco-friendly lifestyle.

Frequently Asked Questions

What are some tiny house toilet options?

There are a few toilet options for tiny homes: (1) All-in-one composting toilets, which combine a toilet seat and composting unit in one system. (2) Incinerator toilets, which burn waste to ash rather than compost it.
(3) DIY composting toilets, which can be made using simple materials and techniques, often at a lower cost compared to commercial models.

How often do you need to empty a composting toilet in a tiny home?

The frequency of emptying a composting toilet depends on factors like the number of users and the specific model being used. Generally, it may be necessary to empty a composting toilet every 2 to 4 weeks for small or light usage, and more frequently for heavy usage.

What is the best way to manage urine in a composting toilet setup?

Managing urine effectively is essential for maintaining a clean and odor-free composting toilet. Some models separate urine from solids, while others collect urine within the compost. For the latter, add sufficient carbon-based materials (such as sawdust or peat moss) to absorb the moisture and prevent smells.

What is the most efficient DIY composting toilet design for tiny homes?

The simplest and most efficient DIY composting toilet design involves using a standard size bucket with a tight-sealing lid, a toilet seat attached to the top of the bucket, and a composting medium such as sawdust or coconut coir. A urine-diverting system can be added for extra efficiency.

How can you prevent smells in composting toilets for tiny homes?

To prevent smells in composting toilets, ensure proper ventilation within the system and maintain a proper balance of carbon and nitrogen materials. Regularly add carbon-based materials like sawdust or peat moss to the waste, and routinely turn the compost to promote aeration.

What are the best split system composting toilets for tiny houses?

Split system composting toilets consist of a separate toilet seat and composting unit, usually installed below the floor of the tiny home. Some popular split system composting toilets include the Nature’s Head Composting Toilet, Sun-Mar Excel, and Separett Villa 9210. Each has unique features and advantages, so it is essential to research and choose the one that best suits your needs

Photo Credits

Composting Toilets are compact: Adapted from Dave Ocomposting toilets. Used via Creative Commons License.