The Truth About Dry Toilets for RVs
When the subject of composting toilets comes up, most RVers reactions range from mild curiosity to shudder-inducing horror. The thought of treating human waste inside the RV scares many people. “Is it smelly?” and “Do I have to touch it?” are common questions. No one likes the thought of schlepping a container of urine through your living space. Or having to stir a tank of solid waste in a tiny RV bathroom.
But are these fears founded or are they RV horror stories of years past?
The truth is that composting toilets have been manufactured since the 1960s. Modern composting toilets are not terribly time-consuming. Dry toilets have less “ick” factor than a traditional black water tank dump station. Many who full-time or do a lot of boondocking are turning to composting toilets. Dry toilets are a way to save on water usage and to make fewer trips to the dump station.
How RV Composting Toilets Work
Composting toilets look like a normal RV toilet but use a non-flushing system. It is best to use toilet paper that breaks down quickly in the system. The toilets typically have a three-chamber system that divides solid waste and liquid waste into separate chambers.
Plant matter such as sawdust, peat moss, or coconut hull is used as a composting base for the solids. When solid waste is added to the chamber, a crank handle is used to churn the mixture. The natural microbes can start digesting the waste and breaking it down into beneficial compost. Later, it can be spread safely onto the soil over tree bases. Dumping the compost happens every 2-4 weeks with full-time use. At that time, you add new compost medium and are ready to go again.
Around 80-90% of the waste entering the toilet is liquid. The newer composting toilets use a fan and a vent system or a heating element that quickly evaporate the liquids so that you don’t have to dump them as frequently or at all (depending on the usage).
Most liquid tanks can hold a couple of gallons and are designed for easy removal and dumping if usage is greater than the evaporation rate. Because the liquids are separated from the solids, the chemical reaction from the ammonia and uric acid in the urine doesn’t have a chance to create the dreaded “port-a-potty stink.”
What About Dry Toilet Waste?
To correctly compost, a toilet must provide the proper environment with a balance between oxygen, moisture, heat, and plant material. This allows the bacteria and microbes to completely breakdown the waste into odor-free compost that doesn’t contain viruses and pathogens and is safe to handle. What is left is a nutrient-dense natural fertilizer.
The “dumping” of the resulting compost seems to be a sticking point for many people when considering composting toilets. For anyone who has done any gardening and used store-bought compost, you will not find a difference in what is produced with the toilet systems.
You should not see or smell any “original” contributions to the compost in its final state. In fact, many municipalities create compost from human waste as part of their wastewater treatment plans.
While the compost is safe to handle and use, it is not recommended to use the compost produced by the composting toilet directly on your vegetable garden as there is an internal heating requirement to ensure compost safety for produce that will be consumed. If you are squeamish, you can always wear gloves to provide further barrier between yourself and the compost.
Full-timers Drivin & Vibin reviewed some of the top Q&As on composting toilets in this video:
How to clean a composting toilet
Cleaning a composting toilet is easier than you might think. Check out this Do It Yourself RV article on 5 tips for a stress-free cleaning.
If composting toilets aren’t for you, you may also be interested in these Two Waterless RV Toilets For Easier Waste Management