How My Composting Toilet ACTUALLY Works – A Review

Macy M164 comments141940 views

I promised I would do a review on the composting toilet after it had been in use for a while. After 6 months I thought it was time for my first in depth review. Besides, I have had A LOT of questions recently on it. Warning, there are pictures into my potty at the bottom. When I was shopping for one I wanted to see what they looked like in the bowl and it was SO hard to find a picture. I never did. So there is a picture of what a composting toilet looks like down in the bowl. 

You can read more about the toilet picking out and purchasing experience HERE, HERE and HERE. Suffice to say, I was not happy with the level of customer service from the get go. I am very happy to say that the technology (or lack there of) of the composting toilet is great. I love my potty!

To Start

I went into this project very leery of a composting toilet. With the same thoughts as many people have: It’s gross. The smell will be horrid. It will be disgusting, a maintenance nightmare etc. This entire project has been fundamentally about learning for me. The toilet was approximately 20% of my entire budget. Even though I had all of these concerns about functionality, I took the risk to find out about this option first hand.  

This is my experience:

The Pros:

I like it way better than a flush toilet, honestly.  There are NO smells at all. There is a fan that creates a constant vacuum of air going to the outside. It is warm when you use it. The unit I have has a small heater. No back splashing and no one can hear you peeing! All pros. 

I have the added benefit of knowing that I am not contributing to a waste system where drinkable water is flushed. That is a lot of energy/chemical use which I get to bypass. Naturally and safely. 

Like I said, I was very leery initially for the same reasons as many others. After six months I have had two issues and zero REAL issues. I will get to those in a moment. I have not yet had to empty the drawer. Based on full time occupancy – 3-4 persons – that would happen after about one year. Currently I am not even a quarter of the way to full. In spring I will do that drawer emptying deed, simply because it’s been enough time. I expect that it will be as painless as they say (pretty hands off and non-gross). Other than that, even as expensive as it is, it is cheaper than installing a septic system. And it is not as limiting when finding a location compared to having to hook up to sewer. It gives me more flexibility.

The Cons

100% of people (I rounded up) do assume it’s gross and disgusting. Also that I am a weirdo for choosing that option. That is the one drawback.  I do have a brother who refuses to use it. James did too, for a little while. He’s fine with it now.  I wanted to have the most normal looking composting toilet so that it didn’t weird people out to use it. I think it does anyway though. Which I understand, it really is ok though!

The two issues:  

Issue 1

The neighbor came over and one day when I was outside working and asked me when the toilet unit ‘cycled’ and if I could reset it for a different time. He and his wife like to hang out in their backyard in the hot tub late at night. It seemed to ‘come on’ when they were out there and ‘really stinks’. This was an odd question to me because there is no ‘cycling’ with this unit. There is a fan that runs constantly. It vents out really high so that it is not noticed. And it does a really good job of being not noticed.  There is also a small heater in the unit that constantly runs. That is all. Completely passive outside of those two components.  

It made no sense at all that it was perfectly fine all day except at this one time every night. I racked my brain on it for a while. Then I noticed that time of night was pretty close to the same time of night that I let Denny out to potty before bed. Turns out he had taken up the habit of pooping in the alley, pretty close to where their hot tub is. And they are right, he STINKS! It’s slightly embarrassing that they think I could smell like that. I don’t want to pretend that my poop doesn’t stink but seriously, it’s not Great Dane level! Once I figured out the issue I fixed it. The neighbors still think I poo nuclear poops though. I have that to think about every time I say hi to them!  So, issue one is a non-issue…

Issue 2

Just the other night, maybe a week ago, it seemed like the vent stopped working.  I have had the power go out before or have to be unplugged for a bit causing the fan to stop. It does start to smell in the house after a bit if I don’t seal off the toilet first. I.e. close the lid. I could still hear the fan running though. I completely couldn’t figure out what was going on. Of course it happened late on a Sunday night. After it was dark and when I couldn’t see to fix it. It couldn’t have happened when there was light when I could do something about it. Even still, it wasn’t horrible and I pretty much convinced myself it was in my head. Just my pregnant nose smelling weird things again. So I went to bed. In the morning I could still smell it.  

I asked James if he could too. He did. But it wasn’t like when the fan goes all out. That is very noticeable, this was hard to tell. I went back around by the vent and I could hear water dripping in it. There was no reason that should have been happening. By noon on Monday it was just fine. I am not positive what happened but I THINK that snow may have fallen into the vent and partially blocked it. As the day warmed up, it melted away and everything was fine. I did decide I need to get up there and put a screen over the opening. I can see a bird or something making it’s way in the 2″ opening and nesting. So even issue two is a non issue. I’m fairly positive it was a weather issue, especially since it fixed itself with the warmer temps.

Special Considerations

As you can read in the previous posts linked above, I chose to get a ‘fancy’ composting toilet (and paid the premium for it) so that I could have it in an urban area. It has passed special inspections (UL) to be ‘safe’ as far as health services are concerned. While this unit is not accepted everywhere it is much more so than say the standard humanuer version. In most cases where it is not readily accepted it is likely because the question has never been raised. Obviously a composting toilet is different than the standard flush unit in a few way. So, the ‘special’ things you have to do with my particular composting toilet. (I am not speaking for the humanuer versions, I don’t know much about them):

  • When you first set up the toilet, after a week or so of use add the provided bacteria. There is a little packet of bacteria that the manufacturer sends with the unit. Put that packet in the tank. It’s as easy as opening a package of ramen and dumping it out. That’s it!
  • At full time use: about twice a week rotate the handle. There is a handle on the exterior unit that needs to be cranked a full turn. I actually have grown to love this little activity. It feels like I am accomplishing an important bit of maintenance (and I am). It also helps me mark the week. I crank it on Wednesdays and Sundays. It’s really no big deal.
  • There is no special toilet paper you have to use, it all breaks down.
  • About 2-3 times a week throw in about a cup of compost mixture. We use a mixture of peat moss (40%) and Sawdust (60%). I have a ton of sawdust I saved from my build. I will be set for years on this!
  • If the unit is below 55 degrees the bin acts as a holding tank only. Composting slows/stops. The weather does not hurt any of the components. It simply sits dormant until it warms up again. This is the reason I am waiting for spring to empty the drawer. I want to make sure it is in composting mode rather than just holding tank mode.
  • To empty the drawer you first fill it. Cranking the handle in reverse will empty the main bin into the finishing drawer. Let it sit and ‘finish’ in the drawer for 6-8 weeks. At that point I hear it is just like potting soil and that I will not be grossed out to empty it into my compost bin OR directly onto my plants. I still don’t think I can use the compost on my veggies. I may have to stick to the flower bed. This happens a max of 4 times a year I expect I will be doing it once a year.

That’s it, it’s just different than a flush toilet. It hasn’t been gross in any ways [to me].  There are actually a lot more pros than there are cons [to me].  I would definitely suggest the unit to anyone else.  It’s weird to talk about potties but I am totally fine with it if there are any questions that are left that I haven’t answered. Please, write them in a comment. I’m sure you aren’t the only one wondering.  I’ll do my best to answer them!

One Last Thing

One important thing I haven’t really mentioned, because my unit does it automatically: A good composting toilet will have a urine separator which does exactly that, separates the urine.  THAT is actually the stinky part of a toilet. If you can keep the solids and liquids separate the smells go WAY down. Urine will smell much faster and much stronger than poop.

The must haves of a hands-off composting toilet include:

  • a urine separator of some sort
  • a vent (preferably with a fan to make SURE the air-flow is going the right way – OUT)
  • depending on your climate, a little heater to keep things above freezing and help evaporate off the liquids.  

There are plenty of people who are good with the humanuer version. (i.e. 5 gallon bucket with sawdust. They sell urine separators for those too.) I just didn’t like the maintenance of those and the fact they would not be allowed in a city center because of health and safety regulations. For some they are a great and inexpensive option though. They certainly function the same way as my expensive toilet. 

Now for the pictures inside the toilet

Turn away if you must (it’s really not that bad…)!



        1. Thanks Nicholas! That IS what I purchased but I was actually sent the electric version, it is a tad taller but works well.

  1. Thanks for sharing. I enjoyed it all….down to the video!! Question, did I miss what you do with the urine after separating?


    1. Sorry, I glazed over that, the unit itself separates everything down in the bin, the heater and fan are in part to evaporate off the liquids. I don’t do anything with any parts, it’s all self managing until its time to dump out the drawer.

  2. Ok ok. You convinced me! I always swore id use a regular, low flow toilet when i build mine. You have convinced me to to at least consider composing. You are right, doesn’t sound as bad as i thought it would be.

    1. People WILL think you’re weird, I can’t help that :). I won’t though, I promise, well at least not for that 😉

  3. Very well written!

    So you know on a regular toilet you clean down in the bowl and the interior sides of the bowl. Is that a possibility for this one? At least on the interior sides where the waste doesn’t sit but it definitely get dirty.

    1. Very good question, yes! You can! You can use warm water and a natural soap (NOT an antibacterial soap, you’ll kill all the good guys from the packet!). You definitely can though.

      1. What are the inside walls of the toilet made of? Porcelain? Plastic? It looks black in the pictures. Doesn’t that make it difficult to find and clean anything that has splattered on the walls?

        1. It is a black plastic, it is black exactly for the reason of hiding anything that has splattered on the walls. It is important not to use any cleaning chemicals in composting toilets, you can use some natural cleaners or just soap and ‘natural’ soaps (no antibacterial soaps or you will kill all the good guys down there doing the composting work).

  4. Urban composting toilet at it’s best, glad there is a solution for you city lovers 🙂 Mind you I still prefer my bucket and sawdust toilet; no smell, no hassle and only about 5 minutes a week of maintenance.
    Most importantly neither of us is using that most valuable resource of water or poisoning it with a host of chemicals.

  5. Wow! Macy.. this is the smallest composting toilet I’ve ever seen! I’ve been struggling with what to use for our tiny house. We are tight on space and the ones I’ve seen you have to step up to sit down. They’re tall and wide and would never fit. Is the tank below? Would you please give me the name of the manufacturer? I’d love to look it up.

      1. do you have any suggestions for a unit that does not have space below? We are converting an old garage on a cement slab.

        1. gosh, I havent done that research for a while, I know people are really happy with the separett, both Envirolet and Sun-Mar have self contained units as well.

        2. If you don’t have a basement, you can keep it really simple using a BoonJon composting toilet. It is a urine diverting toilet that uses a medium like peat moss or sawdust to store the waste until you can take it outside to a composting bin. The entire system is really very user friendly and easy to keep clean. You can also use the urine immediately to fertilize your plants.

      1. The inside unit definitely is, that’s why I liked it, its the tank outside that is bigger! It’s slightly bigger than a 55 gallon drum.

  6. Thanks for giving the follow up! So many of the people who write about alternative toilets just describe installation and then don’t get around to following up. Will you please post again after you do an emptying of the compost? As they say, the proof is in the pudding…

  7. So, this is a dumb question, but when you empty the contents, where do you put it? I’m guessing it’s not already broken down into composted soil that fast, right? Does it smell awful?

    1. Not a dumb question at all! So when emptying the contents you can put the final compost in your garden plants, I have decided I will only put it on non-edible plants even though they say it’s fine to put them on any :). I have not had to empty it yet but I will in June whether it needs emptied or not and I will make sure to talk about it. The waste stays in the bin a year or so so it is fairly broken down but there is a drawer that you empty SOME of the contents into and let it ‘finish’ for two months before pulling it out and emptying it in a garden bed. I am told that at this point it looks just like potting soil with no smell or anything, I tend to believe them because everything to date has worked just as they stated on the website (Sun-Mar). So far there are zero smells, the fact that the solids and the liquids get separated limits the smell a great deal. I would say separating solids and liquids is the best thing you can do to limit smells, better than a fan even.

      1. Thanks, Macy! I would have thought that it would need a lot more time before it became soil-like! So, there are two separate drawers, one for the earlier process and a second one for the finishing process?

        I also thought of another question. Since it has a separator that liquids go into, would it be possible to use a hook-on bidet with it? “Regular” composting toilets don’t accept liquids easily, so I’d written off the idea of a composting toilet until I read about yours. I’ve known people who have stayed in primitive places that use those, and you have to pee on a tree – which does not at all suit me 🙂

        A few months ago, after much research and reading, I added an attachable bidet to my regular toilet and stopped using toilet paper altogether… it has been a wonderful shift! It uses very little water, no electricity, and leaves me feeling much more clean and fresh. I also love the idea of less waste plus saving $ on not having to buy tp. I keep a bit on hand for visiting friends and clients, but that will last quite a long while!

        When I eventually have an off-grid cabin built, I am definitely considering using one of these but would want to use my bidet along with it. Do you think the added water would be a problem?


        1. Two separate steps, yes, one larger composting bin and then the drawer where things finish and get emptied, the drawer is much smaller than the bin since waste composts down to about 1/10th the volume. There are several designs that sound like they will work with the bidet you describe. You may not be able to make it work in a city center since you will probably need to have the fluids empty into some sort of seepage bed. In my unit the fluids drain through the main bin to the bottom of the unit where there is a heater and a small fan that evaporate them off. If there were more fluids there is a drain that they would come out of which is suggested to be tied to a seepage bed or a sewer line. The mechanics of various units vary but it sounds like it wouldn’t be an issue to achieve what it is you want to achieve at all! I strongly recommend composting toilets as a viable solution for what that is worth!

    1. It is in those links at the beginning along with some cautionary tales about their customer service or lack thereof, it is a Sun-Mar

  8. Hi Thanks for your great commentary Soooo… there are no odors detectable coming from the vent or holding tank, Right? Nothing that nosy neighbors could detect? Are these actually legal in suburban areas of California? Wonder where to find out and did you you need a permit for this ? Thanks again

    1. I have to say, Garlic Cat made me laugh out loud, really :). Yes, there are no detectable odors, the toilet vents 10-12 feet in the air and I haven’t noticed any. The neighbor complained one time because he knew I had a composting toilet and he asked me to have it ‘cycle’ at a different time so he didn’t have to smell it. I was of course mortified but also confused because there is no ‘cycling’… it just does its thing. Long story short, we found out it was that I was letting my dog out at a certain time and he liked to poop next to his fence… the guy could smell THAT and though it was me. I was still mortified but we got it cleared up and now he dog cycles at a different time :). If you were closer to 2 story houses you may want to vent up higher, should be at whatever level the roofs around you are and then there is no smells, they get carried away and dispersed even on less windy days… They are legal in many parts of the country, you would have to speak with your local plumbing code inspector to find out for sure. Hope that helps!

  9. Hi Macy I would like to have the model # and the manufacturer of your c. toilet .The above address only took me to your Tiny House site. Thanks

    1. You can find that in the three links listed in the first paragraph, I would just give it to you but there is important info in there about things to be aware of (I am not completely happy with the service)

  10. Thank you for such a great explanation. I have two questions… 1) can this type of toilet be used in the tropics? 2) do they have an equivalent technology to replace a bidet toilet?

      1. As long as the bolts that fasten the seat down are roughly equivalent to those on a regular toilet seat, and the toilet is capable of accommodating a little more liquid than it normally would, you should be able to attach a bidet adapter directly onto it. You’d have to have a water supply close by, though, to tap it into.

        1. The bolts are the same and the unit is a flush OR Dry unit so it sounds like a win. My particular set up is a dry set up so no water.

          1. Very cool that the bolts are the same! And the water doesn’t have to come from the toilet, the bidet has a water supply that just needs to be hooked up, a sink pipe close by will do just fine as long as there is running water of some sort available.

            My biggest concern for doing this was that the unit could accommodate the additional liquid in it.

            Also nice to know that this unit can be used for flush setup also!!

  11. Great review with such honesty & detail. Thank you!
    Which brand & what did it cost? Bought where?

    1. There are three links in the first paragraph that take you to that info, I would just tell you but there are other important tidbit of info along with that info that I want to make seen too, I am not entirely happy with the company and how they approach (or rather don’t) customer service.

  12. This may be a random question, but on the model pictures from your link, it shows that the holding tank below is quite large, is there room for that under your trailer and still clearance from the ground if you were to ever move your home? It seems as though the below surface parts take up a lot of room…..

    1. My trailer is above wheel so there is more room than standard, I do dig down about 6 inches into the ground but I could also just put my trailer 6″ higher on it’s blocks. If I move I just slide it out and put it on the back patio. it is a large unit but I liked that because it makes it more hands off than others. i have to empty the drawer about once a year is all.

  13. Just back from the Mother Earth News Fair in Pa. and I looked (literally) into all the off grid toilet options there. I am also looking into one called the E-Loo out of a company in Texas. Really great to read your post, want all the info I can get before I make my decision. Thank you.

      1. Not sure yet, not building for another 3 years, site considerations will play a major part in my final decision. Will probably go with a self contained unit and the E-Loo would preclude that.

  14. Hi Macy. I find your posts so educational thank you. I have a question. We already live in a Tumbleweed Tiny Home and I want to convert to a composting toilet. Can you please tell me the brand you purchased and provide a link? I would like to get this exact toilet because I trust your research.
    Thank you

  15. Hi Macy, thanks so much for the great info! I am in the process of having my tiny house built (with a builder) and I wanted to use a remote composting toilet like yours but had a couple questions. First… will the part that goes outside be able to fit under a trailer? Or does that only work for houses with foundations? And something my builder brought up… if I have a rooftop deck on my house (above the loft which is above the bathroom), will the toilet need to vent right next to my deck? :-/


    1. each model is a bit different on dimensions, my trailer is not a drop axle so I have more room than most. Even still I did have to dig down about 6 inches to fit it. Mine is a trailer so it is certainly not just for foundations. The toilets vent at 12-14 feet, it doesnt matter where on your house it vents in proximity to your deck, a tiny house is not big enough to get away from it unless you vent it higher, which isn’t THAT feasible. I’m not sure how well it would work with a roof deck honestly. It is noticable on the roof… we found that out reroofing the shop next door to me. Hope that helps!

      1. Oh, okay. That’s what I was afraid of. 🙁 I was really hoping to get one that composted outside of the house but I know I most likely won’t be able to dig down into the ground under my trailer (I’m going to be in a friend’s backyard). And yes that does help about the deck, I didn’t even think of that. So that venting be an issue with any composting toilet then, right? Even if it was a self-contained unit?

        1. I think the fan is the real difference, Composting toilets all work differntly, you can probably find a non vented self contained unit, it just gets more important how you use it. There is SO much difference in this area, A dry flush toilet may be a good option?

          1. It’s pretty confusing on my side too honestly! 🙂 Did you ever think you’d call a toilet ‘pretty cool’? 😀 You’re doing great!

          2. Ha! No, I definitely did not! I was just talking to my friend last night and told her about this cruise I’ve been wanting to go on but had decided against it this year because I needed to use the $ for a decent toilet instead, lol. I heard myself and was like what?!? 😉 Thank you, if you want to follow my saga as it unfolds too, my blog is Love yours! 🙂

          3. hahahaha! That’s awesome! I’ll be following along! Thanks for sharing the link! I love following along!

  16. I’m building with the help of my high school students. I ordered the
    and I can’t wait to use it. I liked it much more than the Sun-Mar only because I can empty the goods right out of the house and the urine diverter connects right into my greywater system. Next week our whole school PreK-gr12 is studying water and they are doing a whole unit on looking at toilets. I can’t wait for the students to learn about composting toilets. My facebook page is

    1. I partially wished I would have known of the Separett and/or the dry flush when I built! I’ll keep tabs to see how it goes, thanks for sharing!

  17. Macy, you mention the fan and the heater that are going all the time. How noisy are they? Would they be too noisy for having the unit in a bedroom? Also, what sort of electrical requirements do they have? Standard 120 volt? Thank you for sharing about this and inspiring others to consider this alternative!

    1. They are not noisy, I have to strain to hear the fan from in the bathroom, the heater is completely silent. it is a standard 120 v plug but could easily be hooked up to a small solar panel, very low draw. Hope that helps!

      1. Macy, I am confused. I thought your toilet was a non-electric model (Sun-Mar Centrex 2000, non-electric).
        I’m experiencing CTC (composting toilet confusion).

        1. Hi Mary, I did originally order the non-electric but the representative who placed the order mis-ordered and Sun-Mar refused to exchange it for the correct unit without me paying a few hundred bucks for shipping… they took the attitude that I should be grateful for getting a more expensive unit for ‘cheap’. I should have complained more but as it turns out that was just the first issue out of several with customer service. I had to make some design changes on the fly since the electric unit was several inches bigger than the non-electric but ultimately the unit works well and doesnt draw much power.

          1. Thanks….would you advise going with the NON-electric, in general? I am the only resident of my THOW.

          2. I think it depends, it was mostly about size for me, it is nice to have the fan to assure smells are going outside rather than inside, I had planned to hook up a small fan to the non electric version too.

  18. Thank you so much for the fantastic review!!! Its so hard to find a review that answers all of questions in one shot. Its like you were in my head! Lol
    I just have one more question for ya, if you don’t mind sharing…what brand Composting Toilet did you buy?
    We love “the look” of it, just like you…want it to look as much like a standard toilet as possible.

    Thank you in advance!

  19. Hi Macy,

    When the urine gets evaporated, there are the salts left over. Is there something that needs to be done with this “waste” seperate from the solids or do they get mixed together? Thank you so much for all your time and effort. I enjoy your blog but love Tiny House Chat. Listen all the time.


    1. That is a great question, I am sure at some point I will need to take down the cover and maybe wipe it out?? I’m not positive, I don’t think it is in the 3-4 year plan though! I am not at full capacity for use, I wonder what Sun-Mar recommends for that!?

      1. I’m in the process of an attempted complete cleaning now. It seems the last couple of gallons of compost are having some difficulty falling through to the bottom. It’s been many years like this is the first time I’m attempting it. Wish me luck!

        1. oh sounds like you have an Envirolet? Let me know how it goes, I hope it doesnt get too out of hand! 🙂

  20. I just bought a cottage last year that came with a Sun Mar composter that’s an older model of the one you have. The bin was 3/4 full of the previous owners “contributions” and I was thoroughly disgusted with my upcoming task of emptying it.

    Having emptied it down to 1/4 full in Spring I found the compost was truly just…compost. It doesn’t resemble poops at all. You would not be able to tell the difference between it and a regular bag of compost for your garden. No foul odour. No hint of toilet paper. Just compost.

    What a relief!


    1. Awesome testimony! I always feel like people doubt me when I say it’s not that gross… it’s nice to have reinforcements! 🙂

  21. Hi Macy! I love reading your blog- all of your info is super helpful! I know from reading your comments that you said you might have considered the Dry Flush had you known about it. I’ve been looking at that mostly because of cost but also because I assumed all composting toilets required a lot of maintenance (composting it yourself) before reading your review. Looking back, knowing what you do now from experience with your toilet and info about the Dry Flush, do you think you would have made the same choice?

    1. There are ongoing costs with the dry flush (the liners) and i think it actually takes a bit more maintenance than my particular unit BUT my unit requires a pretty big hole to be made in the structure of the house (about 10″ hole in the floor) THAT was the scary part. I guess I am glad I have my unit because it is far more hands off BUT had I known about the dry flush I may have opted to not put that big hole in the floor just in case it didn’t work out :). I am glad I stuck with mine!

  22. I am about to buy a ct for my small home. Discovered that walmart, sears and home depot all sell them. must be much more mainstream than i imagined!

    1. I noticed that too! It’s actually WAY cheaper to order any parts or compost supplies from Sears than even going straight to the source! There seem to be a lot of people with CT experience, it’s just one of those things no one talks about! hehe!

  23. Hi. My wife and i are thinking to get a composting toilet just like yours. This particular model automatically separates the urine right? K, so does it then have a special urine jug or something that one must empty on a regular basis? If so, is i quite handy, like could one empty it it a public washroom if necessary?

    1. it does, the urin drops out the bin and is (claimed at full capacity, 4-6 people) dried out via evaporation by way of the small heater and fan. They do suggest you tie into sewer OR attach to their overflow container in case it malfunctions, I am nowhere near max capacity but I have never had issues with the urine not being evaporated off. But to answer your question, yes, you could attach to a jug which hopefully you’ll never have to empty 🙂

  24. Hey Macy! I just bought a piece of property in Boise and am doing a demo before I start to build my tiny house. I’m friends with Kristie and she has pointed me to your blog for some of the good info. I was curious what kind of power requirements your toilet system demands since it is constantly running a heater and fan, and what kind of a system do you have set up for your gray water from showering and the kitchen sink?

    Thanks for all the info!

    1. Hi Ivan! Congrats!

      My toilet (If I remember right) has a max draw of 3.4 amps, I am really reaching back but I think that is right, it’s pretty low, it’s just a computer fan and a very small heater that isn’t always running so most of the time it’s less than that.

      The grey water I have set up to be collected under the house in a barrel. the water goes through a home made filter (a screen on top for any debris and a bucket full of gravel/sand to collect anything else then it goes into the barrel. It’s worked fairly well but there are probably better set ups available 😉

  25. Hi Macy,

    I have read your article and follow up comments with great interest. May I suggest that your followers check out my toilet which was originally designed for boats, my wife and I having lived aboard for years. It is, IMO, the definitive answer to managing your waste in a small space. We have for the past 4 years been developing a permaculture lifestyle on a 1/4 acre residential lot. A complete, indoor, attractive composting system can be had easily for very little money, little maintenance and no offending odors in a way that is actually fun to operate. I call it the BoonJon garden system. Check out my website please and let me know what you think.

    Sandy Graves

  26. Hi Macy! My husband and I are loving your page! We hope to do a tiny house in the future! In looking at your pictures (thank you for daring to provide them!), it honestly looks like the inside of a porta-potty to me! It’s probably due to the fact that the inside is already black. I’ve read both of your posts on this toilet with lots of interest, and gone through the comments and I would be SO grossed out by the idea UNTIL reading your posts! This toilet seems so awesome! I do HATE porta-potty’s though and that it’s just an opening into a big ol pile of poop and pee. And that when you sit down, you’re just pooping on a pile of poop. Know what I mean? From the picture, that’s kinda what it looks like! Can you clarify? I cant tell where the sides of the inside bowl end and the hole into the tank begins, so it looks terrifying 🙂 Also, is there just constantly an opening into a pit of waste (even though the fan is preventing any smells from going into your bathroom/house)? If you don’t mind me asking, what is the exact procedure to use it. Do you push a button and it opens into this pit that you then reclose after you’re done? I totally trust your testimony of non-grossness, but my only education on this is your posts 🙂

    1. Awesome questions and kudos to you for having an open mind, honestly that is more than I had when I dared to use the toilet! 🙂 You are both right and not. I too HATE porta potties. You can’t pay me to use them… I have gone well out of my to avoid them, I have stories… This doesn’t ‘feel’ like a porta potty at all. In theory you are indeed pooping on poop but it’s pretty far away, pretty difficult to actually see even when looking down, the images posted are using a flash. The bin separates the solids and liquids (makes it not smell), the liquids are evaporated off below the bin via the heater and fan, the solids stay in the bin and get covered with sawdust so it’s actually a pretty dry looking environment and honestly looks like dirt and wood chips (with the composting product I use, you can use lots of different things).

      With my unit there is just an opening, about 5″x 10″ that is always open but is about 3-3.5′ down a dark hole, it’s tough to actually see. Some units do have a trap door, IMO those are way grosser because they are generally a lot closer so they can be maintained… oh and there is the chance they need to be maintained! 😉

      Every unit is a little different and functions just a little different, no composting toilet SHOULD stink (porta potties are not composting toilets BTW, just holding tanks you poop into, they DO stink, and are what most people think of when they think of composting potties, they are WAY different though). The main thing is that the solids and liquids should be separated, when they mix it smells, so even though I do have a fan on mine that would push any potential smells out rather than in, the fan is to evaporate the fluids to keep it a hands off unit.

      The process is just to do your business and put some sawdust in the hole after you poop. Once a week you rotate a handle 7 rotations. This might help change perspective on flush toilets and level the playing field a little more 🙂

  27. Hi my name is Tracy. I’m considering having a tiny home built for myself and possibly a future dog pet. You say that your toilet has a fan. How does the fan run ie electric? Where is your tiny home? That is the first problem I’m having is trying to find a place to put a tiny home on before I have it built. I don’t know if I can rent a piece of land somewhere that has electricity, water ability. I’m still in the learning stages. I would like a tiny mobile home that can be moved at different stages of my life. I don’t know if I can be totally off the grid or not, but I would like to be as much as I can . Thank you for any information that you can provide and I found your article very humorous and interesting about the toilets and the Pooh.

    1. Hi Tracy! The fan does run off of electric, the fan is exactly the same as what you would find in a computer tower and could very easily run off of a very small solar panel, many are set up that way. My home is in Boise, Idaho I am not fully ‘legal’, there is a bit of a grey area there, you can read more about that here, It is pretty difficult to find a place to park before having your tiny house ready, it is a bit of a leap of faith, there is a great page you can put some feelers in here, The last resource I would recommend is the eCourses I made, particularly part 1 for your questions here. You can find them here, I will say that it is not as difficult to find a location as you may think for most, it’s just an unknown but it’s getting easier every day!

  28. Hi Macy,
    When you first posted you mentioned your “big belly.” I assume you now have a little one running around so my question is: how long does it take to compost socks, rubber duckies, Legos and the like?
    What I am really asking would be, is there a way to retrieve objects from the container that doesn’t require full bio hazard grear?

    1. This is a great question, I was blessed with some pretty good kids so far, we went through a toilet phase but I proudly say the only one who put anything down there was me… accidentally… I dropped my deodorant down there one day and couldn’t reach it… i got the flashlight and saw it… if I had one of those graby arms I could have got it… now it lives in the toilet until it gets emptied out! ha! I couldn’t even blame the kid!

  29. I never though I would consider composting toilets an option, because I just assumed they would smell like those blue portajons at the fair. After reviewing your notes on these I began I realize how sensible they really are! I live in a rural part of the country with a a septic tank and when the septic has a problem it’s a very dirty job to fix, and it generally happens once a year. Your description of emptying a compost bin sounds much more pleasant. My septic has to be pumped every two years or so and that costs almost $500, not to mention the system doesn’t last forever. Does your composting toilet fit a standard potty seat when the time comes to replace? If it does, I bet the summer 2 in 1 potty topper would be perfect for potty training a toddler.

    1. it is a standard seat and my potty sounds WAY better than yours! 😉 (j/k) Seriously though, picking up dog poop in the yard is WAY grosser!

  30. Hi. Do you or anyone else have experience is operating the SunMar Centrex 2000 unit in temperatures below 55 degrees? The manufacturer says aerobic activity stops below that temperature. Average temperature in my Washington State location from October thru April is below 55 degrees. Would an insulated and heated enclosure be necessary to maintain the minimum air temperature to ensure the aerobic activity remains active?

    1. Hi Ben-
      That is what I have and in Idaho it gets cold too! In the case of cooler weather the unit acts as a holding tank and composting occurs when it get’s back up to composting temperatures. For me it has not been an issue at all, I just empty some of the unit in the fall before temperatures drop. I do have mine under a skirted area which is insulated but it definitely dips below 55 for a couple months.

      1. Thank you for your reply. I’m not crazy about the prospect of leaving all the stuff to accumulate during winter, so I think I’ll try to build an insulated box around the tank and find some way to keep the temperature above 55 degrees.

  31. I do have one poo related question because I braved the photos! Is there any painless way to remove the number 2 residue from the bowl? I am considering a composting toilet, and that is definitely a princess-like concern of mine.

    1. oh sure, a little vinegar water in a spray bottle, easier than cleaning a flush toilet for sure! There is a little brush thing that comes with a lot of units as well but I haven’t found it that necessary…

  32. Hi Macy,
    I’m building a tiny house in Oregon and am considering converting the Sun-Mar dry toilet (the indoor portion of the Sun-Mar system) into a sawdust composting toilet. Like you, I haven’t been able to find great photos of the innards of the toilet, so THANKS for sharing all of the photos you took.

    Does the toilet “bowl” go straight down or is it more bowl-shaped? As in, do you think it’s possible to put a small vessel inside to collect the waste?

    1. It is definitely possible, there is a small taper to it but its about 10″ at the narrowest part if I remember correctly, maybe around 11″ at the top. So sorry I wasnt quicker with this, hopefully its still helpful!

  33. I’m just wondering, how loud is the fan? is it something you can hear all the time or only when you are in the bathroom?

  34. Two quick questions 1) Did you find a solution for cloth diapering with the composting toilet? 2) Have you started potty training Hazel yet, and if so how is she finding the potty, and you with the potty training process? Can you still dump a small potty full down your composting toilet?
    Okay sorry turned into more than two questions!! We really want to put a composting toilet into our tiny house when we build, but I cloth diaper and would need to continue cloth diapering for space reasons (we live in an extremely remote location) so it may be a deal breaker for a few years until there are no more diapers in our house! Thanks so much for such a wonderful post, and for making me think of things that I hadn’t considered with a composting toilet!

    1. I bowed out of cloth diapering, I bit off more than I could chew and immediately got overwhelmed. When Hazel was 10 days old we took off for a two week cross country road trip… In hindsight I should have started when we got back but I had no idea and I basically trashed the whole idea out of frustration… sad. There ARE some who do cloth with a compost toilet, the group Tiny House People has had the topic come up a fair bit (you can search ‘cloth diaper’ and find more. We are potty training, she does great with the compost toilet. She does like to point out other potties and let me know that they are like ‘poppy’s toilet’ (her grandparents). No issues at all on that front though! We did dump her small potty into the big one just fine but we transitioned so she has her own seat insert to use on the big potty. Hope some of that helps!

      1. Thanks so much Macy! It does help, and I totally get bowing out of cloth diapering. Wee Man was so tiny when he first came that he actually needed new born sizes so we transitioned from a disposable to cloth a little later once I had the rest of the ‘Mommy’ stuff somewhat figured out (haha or so I thought!), so I think that made it easier for me.

  35. Thank you for so much detail. I am still not clear about the urine isdue. So I’m guessing feminine products go in the trash and toilet paper can go down the hatch. Am I correct to see that there is no urine diverter on the bowl? My biggest concern is having to deal with a diverter during my “Lady time”. Ugh. It appears that it would not be an issue here. Am I correct? Sorry, a bit graphic, but I need to know.

    1. with my particular unit there is not a separate area, you pee and poop in the same area and the barrel below is perforated so the liquids go through it and it is evaporated off. TP goes in the unit, lady products go in the trash. No need to be sorry, its a very common question! It took a few years but I finally wrote about just that thing! 😉

  36. Thanks for sharing with all the required of knowledge about a composting toilet. It was so much confusing to me before read this article. Great post honestly. It is useful as well.

  37. We are considering a composting toilet. My big concern: when you flush a conventional toilet the water washes the sides of the bowl down. What happens with a composting toilet? And do you “flush” after use? Thank you for any help!

    1. There is no flushing, at least in my unit, some versions have that function. Usually there is just a ‘hatch though’ You poop through it and then close it. A spray bottle with vinegar water nearby is helpful and effective. In my unit (and a lot of other ones) the inside is dark colored (black in my case) so its tough to see anything anyway. I swear to you, it’s not as gross as it sounds ;-). Hope that helps.

    2. SunMar, Envirolet, and Clivus Multrum make flushing composting toilets… Clivus Multrum systems can be found in public use in places like the Bronx Zoo and uses foam to flush…

      Benefits, besides the flush, it the composting bin can be a fair distance away…

      The Envirolet FlushSmart VF system states it can be up to 70 feet away or 12 feet above the toilet and their system uses about 6 ounces of water and a maserater with vacuum flush system, which takes about 30 seconds to reset for the next flush…

      The SunMar system is called Central Flush…

      These are much higher priced systems but can give you a similar experience as using a traditional low flush toilet.

      But depends on the logistics of your living arrangement and how much space you have…

      Using the Envirolet as an example… Ideally, on a property you can place the composting bin unit in a insulated, maybe even heated for winter, shed nearby the house and if you need extra capacity then two composting bins can be linked together for higher capacity and each can service up to two toilets.

      Note, Humanore can take several months to two years to compost enough to be safe to handle with your bare hands… The compost can be used sooner but don’t use for any fruit or vegetable plants if that’s the case… Otherwise let it run its course or switch to a hot compost system for faster composting…

      Vermicomposting can also allow for fast processing of Humanore and the compost tea it produces is more potent than regular compost…

      While compost piles can also generate heat and some people living off grid use that to grow food in the winter as well as heat their hot water and house with heat exchangers to transfer the heat… along with Solar Thermal and/or wood stoves…

  38. How do you “clean” the bowl? Do you need a special cleaner so you dont slow or stop the composting

  39. What a GREAT post! Very informative and really helped the thought of it being “icky” diminish. Thank you!

  40. So I am wanting to go to a compost toilet in a new build. The question I have is this. With the fan. Wanting the smell, there is no smell even with the lid up?

    1. if the potty is working correctly then yes, there is no small whatsoever. Even with the fan it is designed to direct odors out instead of in. That is both good and bad because if something is not acting properly you may not notice it right away. Hope that helps!

    1. There is nothing to do. There are two compartments, the main one that you potty into and then a secondary one where you can move waste to for finishing, via a hand crank, not a shovel ;-). So you crank the handle until some is in the finishing tray, wait 6-8 weeks and then dump the bin out. very hands off process!

  41. hi, so I’ve never used one so a very basic Q. The idea is to keep everything dry as much as possible. So do you just dry wipe after your business? There’s no flushing I presume. So how do you clean the bowl – since if it’s dry I guess stuff sticks? Or you had too many prunes for tea?

    1. there isn’t a ‘bowl’ per-say, its just an opening to the bucket below. You can clean the sides of the opening with vinegar/water. A little moisture isn’t a deal breaker, you just try to limit it. You also want to be careful about using chemicals since most are designed to kill the bacteria that is responsible for the composting. Hope that helps!

  42. hi, what is all that black stuff along the inside the bowl? is it metal or brushed metal? when you get this toilet is it not white and porcelain like other normal toilets? If its your poo/mold that has stained the lining of the toilet; can it be cleaned? Like, if I poo can I then rinse it down so it doesnt get all over it? gross

    1. The inside of the toilet is black fiberglass, they make it black so it doesn’t show the ‘gross’ as obviously, in case there is ‘gross’. A spray bottle with vinegar water will clean it and/or you can wipe it with a paper towel/toilet bush as needed. It is not porcelain anywhere, it’s fiberglass, white outside, black inside. It is a dry toilet so there is no ‘flush’ but you can clean it however you like. The idea behind a compost toilet is to keep solids and liquids separate, my particular model does this automatically but if there is substantially more liquid than just pee you will want to hook it to a sewer as it evaporates all the liquids but if you overload it it won’t work properly, being selective is key. I think it’s probably not as messy as you’re thinking though.

  43. Do you think there would be an issue if the tank did not fill up quickly enough? We are considering using this as a guest house, so it wouldn’t be used very often.

    1. They are actually marketed as vacation cottage toilets, to be used seasonally and not often so I don’t think there is an issue. I was honestly more concerned about using it too much in my application. If it is not actively composting it is just serving as a holding tank.

  44. It sounds great to me. I never use a composting toilet as I didn’t know the actual mechanism of such a toilet. You reviewed great to understand me and I will talk to my plumber friend asap…

  45. Perfectly written! Which means you know on a more regular toilet a person clean straight down in the dish and the inside sides from the bowl. Is the fact that a possibility with this one? A minimum of on the internal sides in which the waste does not sit however it definitely obtain dirty !!

  46. Hey Macy, wonderful guide about your composting toilet. I heard about composting toilet, but didn’t know how those toilet actually works. You made my concept clear. Do you have any recommended brand of composting toilets?

    1. I am happy with our Sun-mar. Envirolet was my other choice because they both offer UL rated units (though they are more expensive!). I liked the way the Sun-Mar works better personally, The Envirolet option has more moving parts that are prone to requiring maintenance based off the reviews when I was looking. A lot of people seem to be very happy with the Separette, it’s a little less costly but is a two step process. Fourth on my list would be the Natures head, it seems to have a lot of happy customers though I hear consistently that smells can be an issues…

      I hope that helps, thank you for your kind words!

  47. Thanks for your article. Wish I had seen this a year ago.

    We got two of the most expensive Envirolet toilets because they seemed to be the only composting toilet on the market that could handle up to 20 people a day and we knew we’d be having parties and gatherings (this was pre-COVID of course) that would be pushing the capacity of most composting toilets.
    Unfortunately, they were a TOTAL FAIL. They constantly tripped our circuit breakers, so we couldn’t run the heat function to dry out the compost. The “poop suspension system” – i.e., a sheet of tissue paper – just didn’t work. And the pumps run constantly – and noisily – and start to overheat.

    Customer service was terrible, and we couldn’t get any support or compensation from them. Finally we made a website to share our story – partly just to process what a terrible and expensive experience this was and partly in the (desperate?) hope that the company will see it and agree to refund us.

    Anyone who’s thinking about an Envirolet toilet, please check it out —

    Be well,

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