Does A Composting Toilet Smell?

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Last Updated on August 9, 2022 by acechapman

All those involved in the topic of camping toilets/motorhome toilets, and eventually the composting toilet, are most concerned about the unpleasant smells or stench.

On one hand, van owners and motorhome drivers are often concerned about an alternative toilet. They notice an unpleasant stench from the cassette toilet that spreads throughout their vehicle. They are determined to improve the situation, but they also have concerns about the stink.

However, we all know that excrement smells bad, especially after using the toilet. Many people also picture several poopy stools in a bucket.

This article will show you why dry composting toilets and composting toilets do not stink. Do you find the composting toilet smell unpleasant? So, let’s start with the basics. No, composting toilets don’t smell or stink.

For over 90 years, the composting toilet is loved and used. It is not without cause. Motorhomes now have composting toilets that are available for around 20 years. In recent years, however, the demand for composting toilets has increased significantly.

Why? You can dispose of your waste at home with the dry composting toilet. For solid waste, the emptying times are longer and you don’t need additional water to use the composting toilet.

Long-term vehicle travel is becoming more popular as well as free-standing. Therefore, this means that the demand for toilets is growing.

A common reason to change the cassette toilet is an unpleasant odor.

composting toilet smell

What is the cause of unpleasant odors in bucket toilets and chemical toilets?

Excreta mixed together can cause a stench. The separation and composting of urine, feces, and other waste have been provided by nature in nearly all living organisms. Excrement exits differently from urine. Some animals, however, have one common excretory outlet: the cloaca. As in birds, the ureter (and intestine) open into the Cloaca to allow for excretion together. There is however no way to collect both excretions in one body for a longer time in living creatures.

The release of gases like hydrogen sulfide and ammonia from excrements can cause a stench. Various bacteria and yeasts cause odors, which decompose nutrients. The liquified mixture is more active than the bacteria, yeasts, and resulting enzymes, which can be found in cassette toilets. The air supply also supports the odor of the mixture.

Cassette toilets are designed to prevent bacteria activity by using liquid additives, which can be chemical or biological products. This reduces odor formation. Some chemical additives can cause harm to animals and humans, so it is important to be cautious with their use. These biological products use enzymes and microorganisms that work well, but they come at a cost.

Some cassette toilet users also use SOG systems. The SOG system eliminates odors by creating a vacuum inside the toilet.

Famous Composting Toilets

What is the cause of strong urine smells sometimes occurring with traditional toilets?

If you consume enough fresh urine, fresh urine will not smell. Some foods, like asparagus, or medications, can make urine smell.

This is one of the topics in our article about cleaning a urinary-diverting toilet. This is because urine does not begin to decompose if it has been stored for a long time, and this can lead to odor formation.

The combination of water and lime, which is what causes the well-known urine smell, is the main culprit. The urine scale, which builds up over time, is another factor that contributes to the urine smell.

The more urine collected, the more likely that an odor will be detected. Most urine-diverting toilets only have one 10-liter canister. This allows for a period of approximately 2-4 days.

composting toilet smell

Is there any unpleasant odor from the composting toilet?

A urine separator is used to continue the naturally occurring separation of urine from feces in the composting toilet. The urine flows into a container and the feces into the container at its back.

The urine canister is kept for between 2 and 4 days so there is no smell. We recommend that you clean the urine canister periodically to remove any urine scale. Learn more in our article Cleaning a urine-diverting bathroom.

The chemical compounds in excrement, such as hydrogen sulfide, are what give fresh excrement its natural smell. They are produced by putrefactive bacteria.

The putrefactive process of amino acids also causes some odors. These unpleasant odors disappear over time just as in your home toilet. A composting toilet that works is possible only by drying solids.

You can achieve this by using a fan or scattering material. Both options aim to remove moisture. They smell as long as they are moist.

You can alter the processes by removing moisture. Some enzymes and gases can only be formed in moist or liquid excreta. Solids are slower to decompose and go through other biological processes.

A composting toilet does not have an unpleasant odor.

Do you prefer litter or fan or both?

Many people now use composting toilets, each with its own method. Some only use litter.

This is okay, as all moisture is absorbed into the litter and then released through the fibers to allow everything to dry. Condensation can form if the litter is kept for longer periods of time.

You can prevent this from happening by leaving the composting toilet’s lid open occasionally or using a fan to regulate it. This allows moisture to evaporate.

The condensation moisture can cause this that collects in the composting bowl and drips onto the mass. The moisture content of the composting toilet will rise and cause an increase in odor.

As an alternative or support to litter, you can use a fan. This allows the feces and air to dry outside and will not cause the composting toilet to smell. Also, the fan removes any odors that have just formed. This helps to reduce overall odor formation.

Some composting toilets have been designed so that solids can only dry with a fan. You can completely dispose of the litter with this composting toilet. Fans used in this area have very low power consumption. This is not a problem, even with continuous usage.

However, you can collect longer if you use a fan. The disposal intervals for items without fans are shorter.

Composting toilets can smell when emptying

The dried solids collected no longer smell like excrement or feces, as one might expect. Disposal is easy. For composting toilets without an agitator such as the Trelino L – Beautifully Designed composting Toile, disposing of the waste is simple.

Fill the composting bag with the solid waste container. Close it tight and throw it in the nearest bin. For composting toilets that have agitators such as NaturesHead, place the solid waste container in a compostable bag before disposing of it.

Nearly 98 percent of composting toilet users make positive statements. Many composting toilet users write about their experiences. The composting toilet is a reliable product. Any composting toilet does not smell or emit any unpleasant odors.


Does a composting toilet really smell? A composting toilet is an excellent solution, especially if the odor was ever a problem with your toilet.

They don’t stink and they don’t smell bad either. Your composting toilet will work well if you easily remove the moisture.

We have an explanation in complete detail of the history behind odor formation. You now have a solid understanding of the principles behind it, and you can work with your composting toilet without worrying.

Image source:

UD composting toilet” by Sustainable sanitation is licensed under CC BY 2.0.

Simple urine diverting composting toilet” by Sustainable sanitation is licensed under CC BY 2.0.

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