How to build a composting toilet system in your tiny home

How to build a composting toilet system in your tiny home

I decided to build a composting toilet system in my tiny home to reduce my environmental impact and gain independence from traditional plumbing. Installing a composting toilet was one of the most intimidating projects I took on during my tiny home build, but it ended up being very straightforward.

In this comprehensive guide, I’ll walk through the entire process of selecting, installing, and maintaining a composting toilet so you can build an eco-friendly, cost-effective toilet system in your own tiny abode.

Selecting a Composting Toilet

The first step is choosing the right composting toilet. Here are the key factors to consider:

Type of Composting Toilet

There are two main types of composting toilets:

  • Self-contained – All components are in one unit. Waste collects in a chamber below the toilet seat.

  • Central – Urine and feces are separated. Waste collects in a chamber installed elsewhere in the home.

Self-contained units are simpler to install and maintain. I went with a Nature’s Head dry composting toilet – a very popular off-grid model.


Consider the toilet’s capacity and emptying requirements. My Nature’s Head can handle over 1000 uses before needing emptied. For my one-person household, that’s once every 4-6 months.


Composting toilets come in different shapes and sizes. Measure your bathroom space carefully to ensure a proper fit.

Special Features

Many composting toilets have extra features like fans, heating elements, and conveyor systems to help waste breakdown faster. I opted for a basic, low-tech model.


Proper installation is crucial for a functioning composting toilet.


Ventilation helps evaporate liquids and provide oxygen to aid composting. My toilet came with a 12-volt exhaust fan which vents outside.


I installed a drainline from my toilet leading to a 5-gallon bucket buried underground. Liquids collected in the bucket drain into the soil.

Access Door

I cut an access door in the bathroom wall behind the toilet to remove composted waste easily.

Level Installation

I secured my toilet to the floor with lag screws and used shims to ensure it was completely level. This prevents leaks and helps waste breakdown.

Use and Maintenance

With installation complete, just add composting medium and start using your toilet! Here are my tips for smooth operation:

Composting Medium

I maintain 6 inches of coconut coir in my toilet chamber. The coir absorbs liquid, reduces odor, and provides a carbon source.

Proper Waste Deposits

Using a composting toilet takes some practice! I keep a small bin with coconut coir next to the toilet to cover deposits immediately. This prevents odors and helps waste compost faster.


Frequent ventilation is key. I run the exhaust fan 15 minutes after every use. The fan helps evaporate urine deposits and freshens the air.

Monitoring Moisture

Too much liquid causes odor and slows composting. I check the toilet weekly and add extra bulking agent if needed.

Emptying Waste

When my chamber fills up, I scoop the oldest, composted waste out through the access door. I spread the safe, usable compost around ornamental plants.

Troubleshooting Common Problems

Even with good use, composting toilets can still encounter issues. Here are some I faced and how I solved them:

Problem: Liquids draining too slowly

Solution: I trimmed the drain hose and made sure the outlet was clear.

Problem: Strong urine odors

Solution: Added more coconut coir and ran the fan more frequently after liquid deposits.

Problem: Drain pipe freezing in winter

Solution: Insulated the drain line.

Final Thoughts

While installing my composting toilet required time and labor upfront, it was one of the most rewarding projects I completed in my tiny house. I enjoy gaining independence from traditional plumbing, reducing my environmental footprint, and producing a useful compost product. With proper selection, installation, and maintenance, composting toilets are a viable, eco-friendly solution for tiny living.