How To Build A Composting Toilet System

How To Build A Composting Toilet System

Composting toilets are a sustainable alternative to traditional toilets that use water for flushing. Instead, they use a natural process of decomposition to turn human waste into compost, which can be used in the garden. This method not only conserves water but also reduces the amount of waste that goes into landfills.

The benefits of using a composting toilet are numerous. First, it conserves water by eliminating the need for flushing. Second, it reduces the amount of waste that goes into landfills. Third, it provides a source of compost for the garden. Fourth, it is more environmentally friendly than traditional toilets that use water.

In this article, we will discuss how to build a composting toilet system and how much it costs to build a composting toilet. We will cover everything from understanding composting toilets to planning and building your own system to maintaining and using the compost.

Disclosure: Best Composting Toilet, as an Amazon Associate, earns commissions on qualified purchases. This informative review article may contain affiliate links. Commission and earnings support our work. This means we may receive a commission if you purchase items from links embedded in the articles.

Understanding Composting Toilets

Composting toilets are a sustainable and eco-friendly alternative to traditional toilets. Instead of using water to flush waste, they use a natural process of decomposition to turn human waste into compost. This process is facilitated by bacteria, fungi, and other microorganisms that break down the waste into a stable, humus-like substance.

There are several types of composting toilets available, each designed to cater to different needs and requirements. Self-contained units are the most popular type, designed for use in a single location. They come fully equipped with all the components needed for the composting process, making them easy to install and maintain.

Central systems, on the other hand, are typically used in commercial or public facilities and are connected to a larger compost bin. These systems are ideal for areas with high traffic flow and require less maintenance as compared to self-contained units.

The simplest type of composting toilet is the bucket system, consisting of just a bucket and a lid. This type of system is best suited for outdoor use or in areas where there is no access to electricity.

The key components of a composting toilet system include the toilet seat, the urine diverter, the compost bin, and the ventilation system. The toilet seat serves as the user interface, typically a standard toilet seat mounted on top of the compost bin. The urine diverter is a critical component that separates urine from the rest of the waste, helping to control odor and speed up the composting process. The compost bin is where the waste is collected and composted, and the ventilation system provides airflow to the compost bin, which is essential for the composting process.

It is important to use the composting toilet properly to ensure that it functions efficiently and effectively. Use the toilet just as you would a traditional toilet, and avoid flushing non-organic materials such as wipes, paper towels, or other similar items. These items will not break down in the composting process and will affect the performance of your system.

When it’s time to harvest the compost, it’s important to cure it for several months to ensure that it is safe to use. Curing the compost allows the pathogens in the waste to break down and helps to reduce the risk of spreading diseases.

Benefits To Building A Composting Toilet

Composting toilets offer a variety of benefits for both the environment and personal use. Here are some of the key advantages of using a composting toilet:

Environmental sustainability

Composting toilets are a sustainable alternative to traditional toilets that rely on chemical treatment processes and water to dispose of waste. With composting toilets, waste is broken down through a natural composting process, reducing the amount of waste that ends up in landfills.

Water conservation

Composting toilets do not require water to flush away waste, making them an excellent option for households and communities that are facing water scarcity or are looking to reduce their water consumption.

Reduced carbon footprint

The composting process in composting toilets generates much less greenhouse gas emissions compared to traditional toilets, helping to reduce the carbon footprint of households and communities.


Composting toilets allows households and communities to be self-sufficient and independent in their waste management, eliminating the need for expensive and complex sewage systems.


Composting toilets can help households and communities save money by reducing their water and sewage bills, as well as reducing the costs associated with the maintenance and repair of traditional toilets and sewage systems.

Health benefits

Composting toilets do not rely on harmful chemicals to treat waste, making them a safer and more natural option for households and communities. They also reduce the risk of water pollution and the spread of waterborne diseases.

Ease of use

Composting toilets are easy to use and maintain, requiring only regular cleaning and the addition of a compost accelerator.

Decorative and customizable

Composting toilets come in a variety of designs and styles, making it easy to find one that fits the look and feel of your home or community. They can also be decorated with plants and other natural materials, making them a decorative and attractive addition to any space.

Planning Your Composting Toilet System

When planning your composting toilet system, it’s important to consider several factors that will impact the functionality and success of your system. First, the location of your system should be well thought out. You want to choose a spot that is near a source of water for cleaning and maintenance, and ideally close to your garden, where you can easily access the compost for use. It’s also important to consider the design of your system, making sure it is practical, functional, and has enough space for the compost bin and proper ventilation to ensure proper airflow.

In addition to the location and design of your composting toilet system, you need to carefully consider the materials you will use. A variety of materials can be used, such as wood, concrete blocks, and metal. However, it’s important to select materials that are durable and can withstand exposure to the elements, so your system will last for many years.

Another important aspect to consider when planning your composting toilet system is its size. This will depend on the number of people who will be using the toilet and the frequency of use. A general rule of thumb is to have one compost bin for every two people. This will ensure that your system is able to handle the volume of waste produced and that the composting process can be completed efficiently.

How To Build A Composting Toilet System

When preparing the site for your composting toilet system, it is important to pay attention to the surrounding environment as well. Make sure that the area is free of trees and other large plants, as they can interfere with the airflow and create a moist environment that is not ideal for composting. Additionally, it is recommended to place a barrier, such as a layer of rocks or gravel, around the compost bin to prevent moisture from seeping into the composting area.

Before building the compost bin, it is a good idea to create a plan or diagram to ensure that the bin will be the correct size and shape. It is also important to choose the right materials for the bin. For example, if you live in an area with a high water table, it is best to use a waterproof material such as metal. If you are using wood, be sure to choose a species that is naturally rot-resistant.

When building the compost bin, pay close attention to the measurements and angles, as this will affect the overall stability of the bin. Make sure to leave enough space for the toilet seat and urine diverter to be installed properly. You can also add additional support to the bin by adding reinforcement bars or brackets to the corners.

The installation of the toilet seat and urine diverter is an important step in the process, as it determines the overall functionality of the composting toilet system. The toilet seat should be mounted securely on top of the compost bin, and the urine diverter should be installed so that it is angled downward to ensure that urine drains away from the composting area. The urine diverter can be made of plastic or metal and should be easy to clean and maintain.

Finally, the ventilation system is installed to allow air to circulate around the compost bin and provide the necessary oxygen for the composting process to occur. The ventilation system should be installed so that the pipes or ducts extend above the compost bin and are angled downward to allow for proper airflow. It is important to make sure that the ventilation system is installed securely and is free of leaks or obstructions. The ventilation system can be powered by an electric fan or can be installed so that it relies on natural airflow.

How To Build A Composting Toilet Outhouse

Building a composting toilet outhouse requires careful planning and attention to detail to ensure that the system is safe, hygienic, and compliant with all relevant regulations. Here are the steps to building a composting toilet outhouse:

Research and plan

Research local regulations and requirements for outhouses, and plan the design of the outhouse based on these regulations. Consider factors such as the location, size, and ventilation requirements.

Choose a site

Select a suitable location for the outhouse, taking into account factors such as the distance from water sources, the slope of the land, and accessibility.

Prepare the site

Clear the area where the outhouse will be built and level the ground. Ensure that the site is well-drained and that the pit will be located below the water table.

Dig the pit

Dig a pit that is deep enough to meet regulations and wide enough to accommodate the size of the outhouse. The bottom of the pit should be sloped towards a pipe that leads to a safe discharge point.

Build the structure

Construct the outhouse using sturdy materials such as treated lumber or concrete blocks. Ensure that the structure is well-ventilated and that the door and seat are secure.

Install a composting system

Choose a composting system that is appropriate for the size and design of the outhouse. Install the composting system according to the manufacturer’s instructions, taking care to ensure that it is properly ventilated.

Install a ventilation system

Ensure that the outhouse is properly ventilated to prevent odors and promote the decomposition of waste. This may include installing vents in the roof or walls or using a passive ventilation system.

Cover the pit

Install a cover over the pit to keep out animals and insects, and to minimize odors. The cover should be securely fastened and should allow for easy access for maintenance and cleaning.

Finish the outhouse

Finish the outhouse with a roof, walls, and a door. Choose materials that are weather-resistant and that will withstand the elements.

Maintain the outhouse

Regularly maintain and clean the outhouse to ensure that it continues to operate safely and effectively. Follow recommended procedures for maintaining the composting system and for emptying the pit when necessary.

By following these steps, you can build a composting toilet outhouse that is safe, hygienic, and compliant with all relevant regulations.

How Much Does It Cost To Build A Composting Outhouse?

The cost of building a composting toilet outhouse varies depending on several factors, including the size of the structure, the materials used, and the location. A basic outhouse can cost anywhere from $500 to $2,000, while a more complex composting toilet system can cost upwards of $5,000 or more.

One of the biggest expenses for building a composting toilet outhouse is the cost of the composting toilet system itself, which can range from a few hundred dollars for a basic system to several thousand dollars for a more advanced system. Other expenses may include materials for the structure, such as lumber and roofing materials, as well as tools and supplies for construction.

It is important to consider the ongoing costs associated with maintaining a composting toilet outhouse, including the cost of composting materials and the cost of any necessary repairs or maintenance. To get a more accurate estimate of the cost of building a composting toilet outhouse, it is recommended to consult with a contractor or builder who specializes in this type of construction.

Maintaining Your Composting Toilet System

Regular cleaning and maintenance are vital to keeping your composting toilet system functioning effectively. A regular cleaning routine should be established, including wiping down the toilet seat and urine diverter to prevent unpleasant odors and maintain a clean and hygienic environment.

Additionally, adding a compost accelerator to the compost bin is a useful tool to speed up the composting process and reduce unwanted smells. Compost accelerators can be made from a variety of organic materials such as leaves, grass clippings, and more.

The temperature and moisture levels within the compost bin are also important factors that should be monitored regularly. The ideal temperature range for effective composting is between 104-140°F, as temperatures that are too low or too high can impede the composting process.

Additionally, the moisture level should be maintained between 50-60% to prevent unwanted odors and slow composting. Excessive moisture can lead to a range of problems and negatively impact the composting process. Maintaining the correct temperature and moisture levels will promote a healthy environment for the microorganisms responsible for breaking down the waste.

Using and Harvesting the Compost

To ensure the optimal functioning of your composting toilet, following the right guidelines is crucial. Proper use and maintenance of your composting toilet system can help you avoid potential problems and ensure a successful composting process.

One of the key aspects of proper maintenance is adding a compost accelerator after each use. This compost accelerator is a mix of organic materials, such as leaves, grass clippings, and other materials, and helps to promote decomposition and maintain a healthy composting environment. The compost accelerator is easy to make, and you can find the recipe for it online or from the manufacturer of your composting toilet.

Another important aspect of composting toilet usage is avoiding flushing non-organic materials down the toilet. This means only using biodegradable toilet paper, and avoiding flushing any materials such as feminine hygiene products or baby wipes that could clog the system and cause problems with the composting process.

Harvesting the compost is a simple process, just remove the lid of the compost bin and scoop out the compost. However, it is important to remember that the compost should be left to cure for several months before using it in your garden. This will allow the compost to fully decompose, and ensure that it will not harm your plants.

By following these simple guidelines, you can ensure the proper use and maintenance of your composting toilet, and reap the benefits of a successful composting process.

Troubleshooting Common Issues

Composting toilets are a great solution for eco-friendly waste management, but they can also encounter a few issues that may slow down or affect the composting process. In this guide, we’ll discuss some of the common issues faced by composting toilets and how to troubleshoot them.

Low Temperature

Low temperature is one of the most common issues faced by composting toilets. The ideal temperature range for composting is between 113-131°F (45-55°C), which is warm enough to kill pathogens but not too hot to damage the beneficial microorganisms. If the temperature in the compost bin is low, the composting process may slow down or even stop.

To fix low-temperature issues, you can check the insulation of the compost bin. Make sure that it’s well-insulated to retain heat and keep the compost mixture warm. Additionally, ensure that the ventilation system is working correctly and that there’s enough compost accelerator added to the compost mixture. The compost accelerator helps to speed up the composting process by providing the necessary bacteria and other microorganisms that are needed for the composting process.

High Moisture Levels

Another common issue faced by composting toilets is high moisture levels. The compost mixture should be moist but not soaking wet. If the compost mixture is too moist, it can cause odors and slow down the composting process.

To fix high moisture levels, you can add more dry materials like sawdust or shredded paper to the compost mixture. This will help to absorb excess moisture and maintain the ideal moisture levels. Additionally, make sure that the ventilation system is working properly, as proper airflow is essential for controlling moisture levels in the compost mixture.


Odors are a common concern with composting toilets, but they can usually be easily fixed with proper maintenance and operation. To prevent odors, make sure to regularly clean the compost bin, add compost accelerators, and keep the ventilation system working properly. Additionally, avoid flushing non-organic materials and make sure to balance the ratio of nitrogen-rich materials (like human waste) and carbon-rich materials (like sawdust) in the compost mixture. A balanced ratio of these materials is essential for promoting healthy composting and preventing odors.

Slow Composting Process

A slow composting process can be caused by a variety of factors, including low temperature, high moisture levels, and a lack of compost accelerator. To fix a slow composting process, make sure to monitor the temperature and moisture levels of the compost mixture and add compost accelerators as needed.

If the composting process is still slow, you may need to add more air to the compost mixture or switch to a different type of compost accelerator. The type of compost accelerator used can also affect the composting process, so it may be helpful to experiment with different types to see which one works best for your composting toilet system.


Composting toilets are an environmentally-friendly alternative to traditional toilets that use microorganisms to break down human waste into compost. Proper site selection, design, maintenance, and use are key to a successful composting toilet system. Proper monitoring and adjustment of temperature, moisture levels, and compost accelerator addition can help ensure that the composting process is successful.

Building and using a composting toilet system can take a little extra effort, but the benefits to the environment and the satisfaction of reducing waste make it well worth it. With the proper care and attention, a composting toilet system can provide a safe, sustainable, and eco-friendly solution for managing human waste.

We hope that this article has provided you with the information you need to get started on building your own composting toilet system. If you have any questions or need further information, please consult the references section for additional resources.