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Do Composting Toilets Smell?

Composting toilets rely on the natural processes of decomposition and evaporation to recycle human waste. If you live in a tiny home and are thinking of buying a composting toilet, it is certain that you have a lot of questions about how they work, if they smell, and whether they will ever stink up your house.

So, do composting toilets smell? Composting toilets use high-carbon content to neutralize the odor of human waste, meaning they don’t smell when used properly.

In this post, you will learn more about composting toilets and tips for using your toilets, so you experience the lingering odor of feces and urine.


What is a composting toilet?

Essentially, a composting toilet is a type of dry toilet that uses a predominantly aerobic processing system that treats human waste through composting. The waterless sewage-treatment system turns human excreta into safe and usable compost.

Considering that composting toilets require little or no water to function effectively, they are an excellent alternative to flush toilets.

Notably, you will need to turn or spin the waste to help it break down faster.

The correct balance between oxygen, moisture, heat, and organic material creates an ideal atmosphere for the aerobic bacteria to transform the waste into fertilizing soils. To ensure balance amongst these elements, you have to add additional material into the system.

A balance ensures complete decompositions and an odor-free treatment.


What does a composting toilet smell like?

A composting toilet should operate odor-free. This means your toilet should produce zero odor as long as you use it properly.

Notably, composting toilets may produce a less noticeable earthy smell, like that of a compost pile. The smell comes from the finished product.

If your compost toilet gets pretty smelly, it is either you’re not doing proper maintenance, or your venting is installed incorrectly.


How does a composting toilet work?

Unlike conventional toilet systems that involve flushing, composting toilets depend on aerobic bacteria to break down waste. These toilets rely on a process similar to that of outdoor composting.

Inside the toilet, human waste is composted with carbon-rich materials, like sawdust, peat moss leaves, and wood shavings to form a soil-like material similar to humus. At optimal conditions, the aerobic bacteria break down the waste quickly and efficiently without producing a foul smell. This end product doesn’t contain any viruses or pathogens, which makes it a perfect nutrient-rich fertilizer.

As far as disposal is concerned, you can use the humus in non-edible garden soils or let a licensed septic hauler handle the end product.


Does a composting toilet stink more than a normal toilet?

The last thing any homeowner would want is having their living space filled with that strong unpleasant smell of old feces and urine, even if it is minor.

A composting toilet encourages healthy, high-temperature, aerobic decomposition. If used and maintained properly, it produces virtually no smell, meaning there is nothing to stink up your house. Indeed, composting toilets smell better than an ordinary flush toilet.

Considering that a wet composting toilet can get pretty smelly, it is best to buy a model that separates the solid and liquid waste into two different compartments. Separating the two minimizes or completely eliminates the chances of having a nasty smell and creates two reusable and eco-friendly products.

Do composting toilets require maintenance? How do you maintain them to prevent the bad smell?

An ordinary composting toilet is designed to perform three utterly separate processes at the same time.

These processes include:

  • Composting the human waste and toilet paper quickly without getting smelly.
  • Evaporating the liquid
  • Ensuring the end product is safe and easy to handle.


That said, a well-constructed and properly used composting toilet will require little or no maintenance. As far as using these types of toilets is concerned, the common practice is to add dry, high-carbon substances to the toilet after use. The high-carbon content neutralizes the odor while triggering the microbes to start the decomposition process.

Notably, a composting toilet can be damaged by weather and other factors.

If you have a composting toilet, you will need to inspect it on a regular basis, most often monthly, to ensure the wall covers are sealed tightly. As part of maintenance, you will also need to inspect for cracks on the base and possible damage to vent pipes. When necessary, repair with ideal materials or replace as needed. Also, maintain the grounds around your toilet and keep surface water from flowing near it.


Tips for using and maintaining composting toilets

Composting toilets are solely designed to process human waste, nothing more. No matter the model or type you choose, they all work on the same basic principle.

Here are tips to ensure composting toilets work best for you:


1. Never use anything likely to harm the microbes

The healthy, hard-working microbes within your composting toilet are the ones that make your toilet useful and virtually odorless. That said, you should avoid adding anything that will likely kill microbes. Simply put, do not use harsh cleaning agents or artificial chemicals like bleach and ammonia products. When cleaning your toilet, it is good to use cleaning agents specifically formulated for composting toilets.


2. Keep the lid down

Keeping your lid down ensures that bugs and insects don’t fly into your toilet and start breeding. Ensuring the cover is down ensures optimal heat inside, so the toilet operates in the best way possible.


3. Maintain ideal moisture content

Composting toilets should be moist, not wet. Thankfully, most models come with urine diverters. Other models come with heaters that help evaporate the urine. An overly wet composting toilet will not only be smelly but will impede the decomposition.



Giving back to the environment is a foundational element of most indigenous worldviews. Composting toilets offer a tangible way to allow nature to flourish and, most importantly, without unpleasant smell. If you are considering a composite toilet, you are not only running away from the lingering odor but also saving water.

Overall, using composting toilets is an environmentally responsible decision.