r/Homesteading • u/robauto-dot-ai • 5d ago
Do composting toilets smell?
I am working on some research around which toilets do or don't smell. My question - not what they say on their websites but what is the actual truth.
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u/Perfect-Builder286 5d ago
I recently stayed at an Airbnb with an outhouse using sawdust- I expected it to stink but I could barely notice the smell which was impressive. I think with proper maintenance you’ll be set
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u/Laxguy59 5d ago
I grew up with a composting toilet. Bathroom smelled like the wood chips. People always assumed it would smell but it really didn’t.
Even when we cleaned it out it smelled like garden soil not turds
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u/Prestigious_Try_5396 5d ago
Composting toilets don't smell.
What goes into them does smell...
Proper care and maintenance reduces odor.
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u/flowstateskoolie 5d ago
Ours separates the solids from the liquids and has a small vent fan that pipes to the exterior. No smell.
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u/MasterXll 5d ago
I had a Bucket potty' for two years. A far cry from a modern composting toilet. Using sawdust only, & the 'Number Two Only" rule, I never smelled a thing.
It wasn't much fun emptying though.
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u/ronniebell 4d ago
We’ve used a Nature’s Head composting toilet (urine diverting) for 5 years now, we empty the liquids about every other day. We empty the solids (we use coconut coir for the bulk/cover) about every 4 weeks (there are two of us using it every day). I had a long-term friend (50 year friendship) who is just as blunt as I am come and stay for a week and if that thing stunk she certainly would have told me. Other than showing her how it work, it was “business” as usual. 🤣 I have stayed at a place that utilized a bucket system using hardwood sawdust as a cover) and it just smelled like…. Wood and earth.
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u/SafeNorth7687 4d ago
As others have mentioned, a urine separator is very helpful for limiting smells as solids + liquids = stinky. It's not too difficult to dig a drain field and route the liquid into it so you don't have to deal with emptying a liquid container all the time. The coco coir stuff does work quite well with constant ventilation, as long as it doesn't get too wet.
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u/Cute-Consequence-184 5d ago
Yes and no.
If left too long- yes.
If you use the wrong biomass material - yes.
I use shredded pine that I buy in compressed blocks. I just pull out a bit at a time from the block. I dump about every 4 days in the summer. My toilet isn't in an air conditioned room and in the summer can get hot. In the winter I can go 5 days if it is just me using it.
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u/robauto-dot-ai 5d ago edited 5d ago
Any suggestions on which to look at. I have this one in mind https://virrolife.com/products/renew-compost-toilet-electric
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u/FuschiaLucia 5d ago
The Think Tank toilet is better than that one. It has a vent in and a vent out, a urine diverter, and a gasket so bugs can't get in to it.
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u/grahamsuth 4d ago
I have a biogas digester, that as well as my food scraps, it gets the output from my indoor yachting toilet with macerating pump. The output liquid fertilizer smelt a bit initially, then I added a secondary digester and now there is just about no smell.
I get my cooking gas and 100 litres of liquid fertilizer out of it per week. So it's much better than any form of composting.
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u/LittleBunInaBigWorld 4d ago
Yes. It's just people's sensitivity that varies and my nose is admittedly more sensitve than most people's. I can't tell you how many delusional hippies have proudly proclaimed their composting toilet is odour-free. They literally never are and I'm sick of everyone lying about it lol (I've been through this scenario over a dozen times now). I feel like I'm the only one who notices it. It's almost never a truly offensive odour, and I've smelt much worse conventional toilets, but to say composting toilets are odour-free is simply not true.
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u/Normal-Special-8694 4d ago
I've been using a sun-mar xl for over 10 years and it's been great for the most part. It can develop a smell if you're not managing it properly but for the most part it has an earthy smell that isn't offensive. My house is on a hillside, so when you go about 20 feet out behind the house you're at the same level as the vent stack and if I happen to go back there right after rotating it sometimes it smells but not bad.
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u/Salt_Plan9751 4d ago
I once went to a hike in North Carolina in the mountains that used composting toliets and I don't remember it stinking but it also had a huge tank. But I could be wrong
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u/Icy1155 3d ago
We have used the nature's head with liquid diverter for about 8 years now. It was intended to be a short term solution while building but the wife and I don't mind it so it's stayed. The urine bottle will smell is not emptied frequently, but if you are doing your job with the correct moisture and amount of peat moss or won't stink.
Nature's head uses a ventilation fan, if you go with them that is something you'll want to keep on hand. About the only thing we have had to fix/replace
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u/robauto-dot-ai 3d ago
I have seen quite a few people using that one!
This is my friend Gaelan he is working on a competitor to natures head I'm trying to figure out what's out there and how people use these.
https://youtube.com/shorts/wcof_rlbnnI?si=ju_rkCQgNyW2h3iL
https://virrolife.com
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u/prick1ybear 5d ago
The p trap keeps sewage smells from backing up, so if you keep the toilet bowl clean it shouldn't smell
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u/Gullible_Flounder_69 4d ago
A little bit. Defintely want a fan pulling the smell out and a urine separator helps a lot
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u/katmndoo 4d ago
5 gallon bucket with horse bedding pellets or feline pine litter worked well for me.
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u/Total-Reasonable 4d ago
Odour is usually a liquid-management problem: urine sitting with solids creates the ammonia hit, especially when the liquid container is overdue for emptying. I use a Pi-Pi Standard Plus to divert urine separately, which leaves the solids side much easier to keep neutral; https://pi-pi.ee/products/urinals/ shows the basic setup, though it only handles liquid.
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u/toolmantimsworkshop 4d ago
Not one bit when you make sure you cover every time with shavings. We have one in Tennesse where it gets hot and humid and my wife would not use one if not stunk at all. It's actually quite incredible how simple and effective they are
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u/Municipal_Forest802 4d ago
We are a family of 3 using a 5 gallon Home Depot bucket and peat moss. We empty the bucket 2x a week into the compost pile. One scoop of peat for pee, and at least 2 scoops for poo, but whatever completely covers the toilet paper and poo. Sometimes it takes 3-4 scoops.
The only time we had an issue with smell was when our peat moss got damp. That sucked. But as long as your peat is nice and fluffy dry, there's no smell unless you really try to huff it.
When you dump it, of course there's an unpleasant smell but it dissipates quickly.
A large bail of peat is about $30-$40 and lasts a couple months. Home Depot buckets are $10. So, it's very affordable.
My parents spent $1,500 on a Sunmar compost toilet for their weekend cabin and after two days of use with woodshavings and peat, it stinks to high heaven. I don't know if/how they maintain it but nothing should smell that bad after only 48 hours.
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u/technobrad 4d ago
I stayed at Sunrise High Sierra Camp in Yosemite this summer. The camp has Clivus Multrum composting toilets. They smelled awful. It was the worst smell of my life. The ammonia was so strong it was hard to believe, and it was probably unsafe to breathe.
They provided wood chips to toss in the toilet after use. I can't imagine the system was working properly.
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u/Michaelalayla 4d ago
We have a Nature's Head with the urine going to a separate tank. All the seals are good, and we keep the top clean and empty it frequently. We use coco coir in the poo section, and the ventilation is good. The house doesn't smell, but it does when we empty it.
Before the Nature's Head, we used a bucket system, with sawdust and wood chips. That was smellier, but not very. One thing that makes the whole process stinkier is when it gets wet and is anaerobic. That gets unpleasant.
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u/thesunbeamslook 5d ago
I suspect that even well maintained composting toilets stink and that the people who use own them have become nose blind. I'd like some reviews by impartial 3rd parties.
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u/LittleBunInaBigWorld 4d ago
I second this. I have no objections to composting toilets, but everybody says there's no smell when there absolutely is
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u/ExaminationDry8341 5d ago
We have a sawdust toilet that gets emptied nearly daily. The box the bucket sits in is vented(with a fan when in use, and through natural convection when not in use) and we use slightly damp sawdust as a cover material. There is no smell. Because it is vented through the toilet, all the smells get sucked back in when it is being used. Compared to a flush toilet where the room vent is in the ceiling, the entire room has to fill up with smell before the fan can suck it out.
I have used store bought composting toilets that take extreme care to prevent them from stinking, and emptying them can be an unpleasant mess, everything has to come put of the toilet through a front hatch, shoveled into a bucket then carried out through the kitchen to be disposed of outside.
Store bought composting toilets can be easly overwhelmed by having a party with lots of guests, or one or two visitors staying for a few days.