Why would you want a composting toilet?


By Greg Illes
We’re now three years with a composting toilet. In that span of time, we’ve used the toilet continuously for anywhere from 3-4 weeks to 4-5 months. Total usage in three years was for a total of about 9-10 months, so I feel that we can speak reasonably authoritatively about it.

Our original motivation was to “do without” a dump station, and use less water. While this may have been slightly naïve, it’s not wholly off the mark. In fact, we do use a lot less water, and generally speaking, we rarely use dump stations.


For those unfamiliar, a composting toilet uses either peat moss or coconut coir (chopped hull) as a composting base, and has a “bin” to contain it. The toilet seat sits above the bin, and poop gets dropped down into the compost medium. A “churning” handle mixes it all up so that natural chemical processes can take place. Other than initially dampening the compost medium, no water is required.


After using the toilet for a while (more about this later), the “mix” is emptied out and new compost medium poured in. The mix can be spread over shrub and tree bases, or tossed in a trash receptacle. Although it seems like it should be gross, it’s surprisingly not so. The composted poop looks (and smells) like dirt. Really.

In fact, the whole structure and process is amazingly clean, neat, and odor-free.

A clever mechanical design separates the pee from the poop, which is essential for odor control. And yes, really, it does it very well, for men or for women, sitting or standing. But the pee bottle holds only a couple of gallons, and while this seems a lot (well, it IS a lot), that’s only enough for two people for two days, and then it’s brim full. But it’s easy to remove and empty, and it can be poured into a campground toilet or (where permitted) nearby foliage or rocky drainage.

Composting toilets have been in use for decades, but mostly in boats and remote cabins. At the time we bought ours, there were two brands that seemed to dominate RV and boat usage today, the AirHead and the NaturesHead models. Since then it appears that the genre has been increasing in popularity. If you develop an interest, some new research would be in order. Just be sure you get a urine-separating design, for this is critical to odor control and easy waste management.


Image9After many years of weeks-long RVing, we learned that our gray and black tanks would fill at about the same rate, and our fresh water would decline along with them. Our tanks were 75-37-39 gallons. So it was easy to conclude that nearly half of our water (the whole black tank minus our wastes) was being used for waste management.

Sure enough, after converting to composting, our water supply endurance went from about 8-9 days out to 12-14 days. For boondockers, that kind of advantage is pure gold.

2014-01-16_DumpingNotWe also had discovered that it was not always a piece of cake to find a dump station. With the composting toilet, we often didn’t need one.

Lastly, although we personally never had much issue with stinky holding tanks, or broken sewage hoses making a mess, we’re very happy that we don’t even have to worry about such things any more.


With a black-tank and dump-station configuration (the traditional RV), there’s only one time you have to deal with waste, and if you’re careful, you can stay clean and tidy and unsmeared. But with a composting setup, there are daily or bi-daily pee dumps. Depending on how often it’s used, there are weekly-to-monthly toilet recharges. Plus, instead of flushing, the mix must be stirred with each use. That’s about it.

Recharging is pretty simple; you do have to carry peat moss or coir (we prefer the latter). Hydrate some new filling, pour it in. This can be done inside if the weather is bad, but it’s also easy to take the whole toilet outside for processing. We usually do it when we don’t have lots of neighbors, but it wouldn’t matter that much either way.

To take full advantage of the radical toilet, we like to dump gray water wherever it’s legal to do so, in order to avoid having to visit a dump station. This can take some creativity (and a long garden hose), and some research on occasion. BLM land, for instance, is very lax, and in many locations you simply must be 100 feet away from camps, roads, water, etc. Campgrounds and parks all have different regulations. In British Columbia, Canada, dumping of gray water is specifically forbidden almost everywhere – so the advantage is reduced, but of course we’re still saving water.

Emptying the pee bottle does add a novel camp chore, since it needs to be done almost every day. Some composting toilet users choose to route their pee into the (now-unused) black tank, and make an occasional stop at a dump station to empty it. To each his own.

[CAVEAT: Gray water dumping is a big topic; just do a search and see how many hits you get. There are many regulations, some of which are in conflict with each other. If in doubt, DON’T. You could get ticketed (or worse) just as if it were raw sewage.]


We are very aware that a composting toilet is not for everyone, and we’ve talked to lots of folks about it. Some people that we’ve talked to were somewhere between disgusted and terrified, just at the thought of having to give their guests instructions on how to use it. Others had a strong aversion to carrying a big yellow bottle of pee across a campground to the public toilet.

It is, after all, waste management, and as such, crosses the boundaries of many people’s “yuck” factor. In addition to this, many people aren’t repelled as much as disinterested – they simply don’t have any issues with black tanks and dump stations – it’s just part of RV life. Many RVers go from RV park to park, where water is unlimited and so is sewage disposal.

But for the avid boondockers like us, who always seek greater freedom in both water and waste management, composting might be worth a look.

Greg Illes is a retired systems engineer who loves thinking up RV upgrades and modifications. When he’s not working on his motorhome, he’s traveling in it. You can follow his excellent blog at www.divver-city.com/blog


Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.

newest oldest most voted
Notify of

I am researching compost toilets because my boyfriend has decided to live in an RV and wants to install one. As far as can tell it is even grosser than I thought. There is no benefit to humanity or the environment in general that is worth such a disgusting thing. Modern plumbing was invented for a reason.

Kate Persondek

What do you do with the solid waste? We’re interested in composting toilets in our RV, but we don’t know where to dispose of it safely (and legally). We won’t be at a home base often enough to just add it to a composting pile or anything like that.


I personally don’t have any experience with a composting toilet. I do have a few friends who do have. They are split on it’s effectiveness vs convenience. Two of the four have actually removed their composting toilets, one went to a cassette system, and the other went back to their original system. I’m including here a link to a video, that could prove interesting: https://www.youtube.com/watch?v=vM71d8wMuUU
Enjoy …..

Kathlene A Lopez-Martin

The composting toilet was the first thing I thought of for my TT. I’ve cleaned houses for a living, didn’t want to spend time looking for a dump station. Now that you say half of your water was for waste tank, even better for the toilet, FOR ME!


Actually, if you using a composite toilet merely because you use too much fresh water, you are doing it wrong. You should NEVER use fresh water to flush your toilet when boondocking. If you want to conserve fresh water, install another water pump separate from your fresh water system, and connect the suction to your gray water tank and use grey water to flush your toilet. You can remove the hose in the back of your toilet from the fresh water and connect the new water pump from your gray water supply and flush as normal.
This will accomplish 2 things: one it will help your gray water tank from getting full, and two you will have your fresh water volume the same as before just for regular use.
Keep in mind, the book says about one pint of water is needed to flush in normal usage. If you have a 30 gallon black tank, that will take 2-3 weeks before it will need dumping.

Ray L

We also spend most of our time boondocking. Recomendations of good systems ?



Thank you for the links and the rest of the info. Greg, excellent point about the diapers- maybe Liz will give her comments soon.


Bill Lampkin

As for diapers in the trash, they go to a ‘sanitary landfill’ and are buried under clean earth cover. In modern landfills, the entire ‘bottom’ of the landfill is covered with a welded, impervious liner to capture any leachate.

Bill Lampkin

You are not gaining any advantage from the composting toilet for boondocking, as you say you must empty the ‘pee’ container every day. That means you must find a toilet every day, so then you can’t call that boondocking! I don’t know of anywhere that allows disposal of pee to the ground. Liz’s comments are on the money. Yes, the birds and the bees and the monkeys in the trees do it that way, but mankind has a choice. Proper sanitation (water and wastewater treatment) is the greatest public health improvement in the 20th century. Let’s not go backwards now.


For greater clarification of why one needs to have human waste compost piles sit for 6 mos to a full year before they are safe for disposal, I suggest you follow up these links:

Survival of Fecal Coliforms in Dry-Composting Toilets

EPA on Composting Tilet Safety –

Chapter Six – Worms and Disease, page 109, in Humanure handbook –

Turns Out That Using Human Poop to Fertilize Crops Isn’t Such a Great Idea – Pathogens, pharmaceuticals, and worms common in human composted manure

Many other articles by epidemiologists, EPA, FDA, and scientists are accessible online. Be careful – the online literature is full of promotional stories posing as serious research by composting toilet manufacturers, distributors, enthusiasts, and green party co-religionists who are blind to the flaws of current small-scale composting of human waste with wet or dry composting toilets. It is an appealing idea but is years away from an effective technology to safely convert a dangerous biological product into something safe to spread on plants.

As for baby diapers – it is a necessay evil since the alternatives are worse: banning disposal diaper use means the rest of us will be forced to use the same washing machines used earlier that day to wash loads of poo-laden diapers. Given that, we accept the smelly inconvenience that disposable diapers will be used and end up in campground waste bins. Fortunately, there are not that many RVers with children still in diapers.

But making the problem worse would be to promote dumping bags of partially-composted human waste in trash bins. Unnecessary when there are many safer – albeit more inconvenient – network of sanitary dump facilities where the black and grey water is properly treated or retained for six months or longer in leach fields, cess pools, or shifted to public treatment facilities.

If you want to be off the grid and avoid waste disposal but not harm the environment, look into incinolets or storburn type waste disposal units that reduce human waste to nontoxic ash. The only two downsides: considerable power required for each burn cycle, and poop being incinerated hasa distinct aroma unsuitable for campgrounds.


I like Liz’s comments. She sounds like someone with a background connected with the subject. I’d like to hear more about that too if she’d chime in with it. Thanks Liz.


Sorry…but from a hygiene and public safety standpoint, the semi-composted material coming out of that small toilet (feces mixed with coir for 2 or 3 months is **unfinished** compost) is still full of pathogens at the time you are blithely discarding it wherever. It may smell nice but increases the spread of all the risks which led modern countries to devise complex sanitation and treatment systems to avoid the spread of diseases.
Real composting toilets use large holding containers and can be swapped out to continue real composting undisturbed for another six months. RVs lack the space to do that. These small composting toilets are a boon to cabins and fishing camps with extensive grounds, but only a novelty to RV boondockers who lack an understanding of how long it really takes to make feces safe for disposal. What one gets from Airhead and other small composting toilets — is not fully composted — but a public health hazard to everyone where the semi-composted feces is being placed: in garbage bins, spread around flower beds, or other places where fully composted material can indeed be discarded.
Grey water, filled with rancid food oils and fats, bits of decaying food particles, and what washes off showering humans (which includes fecal specks, urine, skin flakes, ooze from any sores or skin conditions, medications and lotion)…belongs only in treatment facilities. Never on the ground where you think others might never step or park.
The crush of humans in overused RV and boondock spots only increases the area pathogen load which is already compromised from all the traveling pets urinating/defecating around those spots, humans cooking, spilling food, liquids, spills, or leaks from aging campground sewer pipes, or black water spills from aging RVs or inexperienced campers.
Let’s keep RVing safe in a time of increasing contagious diseases and overtaxed facilities. Too many communities are already looking for excuses to shut down parks sitting on land in scenic locations perfect for redevelopment. Word that RVers are strewing on the ground or plopping into public trash bins their untreated or partially-treated sewage will be all it takes.


It’s a common practice in Mexico to put used TP in a trash can near the toilet. I have never noticed an odor.

Greg Illes

It is a great question Pam.

When we first started using the toilet, we tossed it in with the compost. It worked okay, but the paper did not break up into small bits, with so little moisture (compared to a black tank). So after a year or so, we started putting the toilet paper in a small waste basket. We just fold it over and drop it in — surprisingly, there’s just no stink from such small amounts. Even if we don’t empty the basket for a few days, no problem with odor. And I can tell you that my wife is VERY sensitive to “off” smells, so if she can’t smell it, it doesn’t stink, period.

Tommy Molnar

I toy with this idea all the time. I like it. Wifey? Not so much. In fact, her comment is always “No way”. So I’m having an uphill battle here. Since we do most of our boondocking in NV in the middle of nowhere, grey water is never a problem to get rid of. Quartzsite is another story . . .

I’ll keep reading and ‘mentioning’ this to Wifey and see if I can sway her thinking. Meantime, we’ll just do what we’ve always done. Get to a dumpsite every two weeks or so.


What about toilet paper? Do you keep a trash can for it? And how do you keep THAT from getting really stinky?