Composting Toilet Frequently Asked Questions
This detailed post should answer most frequently asked questions regarding URINE DIVERTING composting toilets. Please add your own questions, and I will answer them.
Capacity
How often should the toilet be emptied?
If four people are using a full sized toilet like the Thinktank on a daily basis, as their only toilet, then a container will last about 2-3 weeks, depending on how much toilet paper is being used. Smaller toilets will be emptied more frequently. When full the contents are usually placed in a compost bin on your property. See my page on composting human waste. It’s easy! But you need to be careful.
How is it possible that the container with solids so rarely has to be emptied?
removable inner bucket lined with compostable bag
Urine accounts for about 85% of the waste volume and is routed separately away from the toilet. This increases the storage capacity for solids greatly. The container is easily replaceable and if the amount of users increases one only change containers more often.
Odor
Are there unpleasant odors indoors?
No. If the fan runs continuously the there will be no unpleasant odors in the room. When installing the toilet, make sure that the venting pipe is properly sealed with silicone. The easily accessible fan filter should be cleaned
regularly as well as the insect net at the end of ventilation pipe.
Are there unpleasant odors outdoors?
No. Because the urine and feces are not mixed, there is never any latrine-type odor from a urine diverting toilet. A certain amount of odor may be present outdoors, however, when and shortly after the toilet is used. If the venting can be routed to the back of the house, it is usually suffice to just route it straight through the wall. If the venting pipe must be routed through the gables or to the front of the house, it should be extended upwards or routed through the roof.
Are there unpleasant odors from the leaching bed/soak-away?
Typical drain pit
No. It does not smell since the urine is let out under ground where it percolates harmlessly away. The drain rocks in the leaching bed are usually covered with landscape cloth, topsoil and grass. There is no way this can smell if done correctly.
Are there unpleasant odors from a urine storage tank?
No. A P trap or waterless odor seal may be needed in some situations. See below.
Must the urine waste pipe contain a Ubend, water seal (otherwise known as a p- trap), or a waterless odor seal like the Hepvo?
Usually not. The faint odor that may come from urine is drawn out through the venting pipe with the aid of the fan.
Is there any odor when I spray the diluted liquid on plants?
mix urine 10:1 with water if using as fertilzer
Not usually. There may be a very faint, temporary odor. It depends on the extent to which it is diluted with water.
Are flies a problem with these toilets?
Problems with flies are uncommon. There is a screen on the vent. Keep the fan switched on at all times just to be sure.
Ventilation
Should the fan operate continually?
venting options (3 are shown – you only need 1)
Yes. This keeps the housing dry and extends the lifetime of the fan. If the fan has to be switched off, place the lid on the container and remove it.
Which is the best method for routing the venting pipe, through the roof or straight through the wall?
It is always easier to go straight through the wall. When routing the venting pipe through the roof, the work is more difficult, as is ensuring good seals. Remember not to route the venting pipe to the house entrance or other
places where people gather.
How much airflow does the fan create?
There is no simple answer to this question because the airflow is very dependent on the length of the venting pipe and the number of bends it contains.
Is an additional fan needed if you have a shower in the same room?
No! All ventilation from the bathroom shall go through the toilet fan that runs continually.
Does the venting pipe need insulating?
Only if you notice condensation on the pipes.
Can the ventilation be run through a chimney stack?
No. We advise against it since moisture from the bathroom can destroy the mortar joints. Also, the plastic ventilation pipe can melt if it is run through the chimney stack.
Urine outlet
Where do I lead the urine?
You have three options for the urine outlet:
1) connect the pipe or hose to the greywater system.
2) make a simple leaching bed/soakaway.
3) use a tank.
gray water connection drain pit urine tank
Please check local regulations.
Does the urine waste freeze in the winter?
Not under normal circumstances. Urine freezes at about -5ºC (23ºF). Ensure that the urine waste pipe has a drop along its entire length and use at least 50 mm (2″) pipe outdoors. It may also be a good idea to insulate the piping sections that run outdoors.
How can I make a simple leaching bed/soak-away? (Also called a French Drain)
drain pit
Dig a small hole in the ground, measuring about 2′ X 2′ X 2′ deep. Fill it with rocks. Before covering the leaching bed with soil, put landscaping cloth over the stones to prevent clogging. The urine outlet can be led through or under the plastic film. Please a check with local authorities if in doubt.
Am I allowed to connect the urine waste hose to the greywater system?
Urine is sterile and does not pose a health risk. However, the regulations vary. Please ask local authorities.
How steep a drop must the urine waste pipe have?
It is important that the urine waste pipe drops along its entire length, so gravity can drain all liquids. A steeper downward drop lessens the risk for deposit build-up of urine salts or ice.
Is it possible to reduce the risk of urine salt deposit build-up in the urine outlet?
Yes. We recommend rinsing the urine basin with a small cup of water after each visit. You can also use a little enzyme drain cleaner once a week.
Maintenance and care
Do I ever have to add anything?
In the container inside the toilet, the contents should be left to dry and lose volume. It is possible to add absorbent cover material like wood shavings or wood pellets before the first use, and after each solid use, but this is optional. Cover material will reduce the slight odor at the exhaust vent even more, and may make the toilet nicer to use for any sensitive people that cannot stand the sight of human waste. However, it reduces capacity.
urine flows down forward hole
Does the toilet function well for women?
Yes. The urine bowl has been tried and tested by both older and younger women to ensure that the urine is separated into the right place.
Does the toilet function well for small children?
Yes. A child seat may be needed, depending on the toilet you choose.
child seat is included
Which type of toilet paper should I use?
You can use normal toilet paper.
Should I throw toilet paper in the container?
Yes, toilet paper helps keeping the contents of the container dry and divided which facilitates the handling after the storage period.
Does the toilet function in cold rooms?
Yes. Urine diverting toilets are not room temperature dependent. Cool temperatures may slow down or stop the composting process, but it will resume when things warm up. Much of the composting actually takes place later, when you have removed the inner bin and set it aside as instructed.
Can I use compostable bags in the container?
Yes. When emptying the toilet, you may dump the contents with or without the bag into your compost area. However, the bags take a much longer time to compost.
How long time does it take until the compostable waste bag disintegrates?
There is no simple answer to this question because the disintegration is depending on the biological activity in the composter. It breaks down much faster in a hot composter, and with exposure to sunlight. Since the bag is designed to endure the conditions inside the container, it will also disintegrate slowly in the ground or in a composter. If you are combining wood shavings with the solid waste, it is quite easy to empty the bucket into your composter without the compostable bag. This results in much faster composting.
Can the toilet tolerate freezing temperatures?
Yes. Composting may be delayed.
What do I do when the container is full?
Put the lid over the container, tilt the container towards you and use the sliding surfaces to remove the container from the toilet. Dump the contents into a compost bin. After it has fully broken down, use the compost on non-edible plants.
put lid on inner bin and remove
Miscellaneous
Do I need to obtain permission from the authorities before installing the toilet?
Most areas now approve of and support the use of composting toilets. However, regulations may vary. Please check carefully.
Can I install the toilet myself?
Yes. There are not usually any problems for the competent handy-person. Its a simple job that could also be done by a professional at low cost.
Where can I buy one?
On my shop page, or by calling Composting Toilets USA toll free 1 888 361 0014 – toll free in North America.
Hopefully this composting toilet FAQ page has answered your questions. If not please call me directly. I will answer the phone or get back to you asap.
Help, I have a Separett Villa 9215, newly installed and it is not draining out the gray water pipe. I learned this when it overflowed into the main basin of the unit. Additionally it is leaking at the connection to the toilet and leaked all over the floor. Am I missing something on the function or is something not right on the installation?
The light sensor on my separett tiny does not come on. It is new and I have positioned the bucket and urine container properly.
I have this toilet in my RV . I was told to rinse down the urine evertime and do a vinegar rise every other time to prevent blockage . now it’s draining extremely slow even after taking the precautions. someone Said to use hydrogen peroxide and then it made it even worse. I can’t find anything online on how to fix it. this is my permanent home and I need this fixed asap
Your drain line has become blocked. You need to unblock it. Try enzyme drain cleaner. If that doesn’t work you will need a small plumbing snake. Use a little enzyme drain cleaner every week to prevent it happening again..
Down to the Thanktank and Separett. Which one should I go with, is my question. Both appear to have issues; such as – fan failures; use by women; and disintegrating bags.) My application will be easy to vent and I will divert urine to a gray water system. Any further insights to help me make a decision are greatly appreciated.
That’s easy. The Thinktank is a better toilet – by a significant margin. The Separett has a few issues, whereas the Thinktank has zero issues. The Thinktank was designed to improve on the Separett.
1) Fan failures. There has never been a single fan failure with the Thinktank. It uses the best fan in the world. Eventually all fans fail, and when that happens the Thinktank comes with a spare! Plus replacement fans are reasonable priced.
2) Use by women. The Thinktank trap door stays closed unless going number 2. If it is closed, women (and men) can pee anywhere they want. It will be funneled into the correct space with the ingenious and patented urine drain system. This also allows men to stand, while they should sit with the Separett. If the women occasionally pees while the trap door is open, it’s not a problem – it will usually funnel into the correct area anyway.
3) Bags breaking down. The Thinktank comes with very strong Glad Tall compostable bags. These rarely break down in side the toilet. These and other excellent compostable bags are now widely available. Avoid cheap dollar store compostable bags.
If you saw them side by side, you would choose the Thinktank. The only advantage to a Separett is that it is slightly less expensive.
The Separette 9215 uses a fan constantly. How do I use it in a wet bath? The RV I plan to purchase has a wet bath and if using the shower, the toilet would get all wet. How should the toilet be installed? Does it have an AC outlet or is there another way to supply the electricity for the fan?
You can’t easily use any toilet that is powered by electricity in a wet bath. Virtually all waterless and composting toilets – and certainly the good ones, have fans. These cannot be used in a wet bath. You might be able to use a solar vent, and not power the toilet, but it’s not certain you will move enough air with a solar vent.
I’m installing my seperate toilet but the concealing flap is disconnected, its attached by a wire to the seat but it is not in a fixed position. I would greatly appreciate it if anyone could instruct me on how to attach .⁹
The first time I emptied my Separett, the waste bag had broken down already, leaving a mess in the bucket to clean up. How long do the bags last before they break down?
Usually about 30 days but it varies widely depending on how much moisture is in the bucket. If you turn the bucket upside down and dump the contents in a compost bin, you should only rarely need to rinse out the bucket. There are compostable bags that last longer, but then they can take too long to break down in the compost bin.
Our 9215 allows odor into the room. The Blue opening door appears loose and has a half inch gap around it since new. The screw holding the door on appears stripped as I can’t remove it or tighten it. Is it supposed to be that big a gap? Bought this unit last year and stored it until 2 months ago while building home. Follow all installation instructions to a tee.
It sounds like the fan is not working, or is blocked. It has nothing to do with the blue view screen, which does not fit tightly. A 1/2″ gap is normal. Test the fan, make sure the screens are clean inside and out. You should feel air blowing gently when you place your hand over the exhaust vent outside.
Any idea if the Separett Villa 9215 bags that came with the toilet contain PFAS?
They are made by Biobag. Biobag says: BioBags are made from a resin derived from plants, vegetable oils and compostable polymers. The more detailed answer: BioBag ® products are made from a compostable resin named Mater-Bi®.
We’ve been using the Separett with a holding tank for the urine for about two months. For the first month it was infrequent use for liquids. We are now using it a bit more than before and the urine smell is almost unbearable. I guess it’s just the direct line to the tank that comes back into the room. Is there something we’re not doing right with the install? We are pouring water in after every use. Is it just a matter of adding a tablet to cover the smell? Our plan was to use the urine as fertilizer. Does using a tablet make that inadvisable?
When you drain urine into a tank, odor is possible. I’m not sure why but it is not a problem for everyone. Fortunately, the solution is simple. You need an odor seal, or P Trap. Separett has a P Trap which uses a small amount of water to prevent odor from coming up the pipe. This is similar to the common P Traps that are under every sink. However, it takes up a bit less space. I’ve also had very good success with a Hepvo Waterless Odor seal. These can be purchased at RV stores and online. I hope to stock them within a couple of months.
I bought a Separett and installed it.
When I press the button the fan does not work, seems as though there is now power going to the unit.
I have emailed Separett twice and left two messages with no reply.
Can you assist?
Thank you.
There is no button to turn the fan on or off, so I am confused. There used to be a 2 speed fan, and maybe that is the button you are referring to. You will need to persists and call Separett USA.
Hi. Thank you for your website. We have the Separett Villa 9215 in our travel trailer for over a month now and love not having black tank. However; during tow days, we notice a pungent odor that is otherwise not present or barely noticeable when we are stationary. To clean, we used water/vinegar in a pray bottle and spray the urinal part every time we urinate. Do you have an idea on why this is happening or any suggestions on how to minimize the smell? Any suggestions is greatly appreciated.
Odor is coming down the pipe. You have the wrong vent cap installed. You can buy a vent cap designed to prevent this at an RV store.
To prevent having to cut a hole in the wall for outdoor venting, I have seen that some composting toilets (compoosttoilets.com) use an activated charcoal filter. Can a charcoal filter be used on a Separett instead of having to vent outside?
I will be buying an RV to live in while building a house and don’t want to damage the RV so it can be resold when the house is built.
It has been tried and does not work well in our experience. There is stinky air inside a toilet. No filter is going to clean that air sufficiently. You will get odors. Furthermore, the circulation of fresh air is essential for composting to occur (with a Nature’s Head) or to dehydrate the waste (the Separett).A properly installed vent is not damage to your RV. It’s an advantage. If they don’t need it for a toilet, it can supply fresh air.
Vast experience has proven to us that a vent is absolutely required for an odor free installation, with a fan. No shortcuts, sorry to say. You need a proper, professional installation with a dedicated vent or fan.
My bags are desenegrating in the container. What’s wrong?
Nothing is wrong. Compostable bags will compost. If the waste is very wet, or it sits in the bucket for a month or more, they will start to break down, as they are designed to do. You can try absorbing excess liquid under the bag with an absorbent material. Under normal conditions, the bags should be intact for about a month. You never pick the waste up by the bag. Always take the entire bucket outside, and dump the contents bag and all into the compost bin. If it has broken down, the bucket just needs a quick rinse.
Is it possible to vent through the floor?
Yes. Keep it as short and straight as possible.
My wife sprays a wide pattern ,is there a bigger urine blocking bridge? Can I order just the part# 10349 and add on to it? I saw where one woman would a paper plate. I am looking for something a little better. We have a Villa 9215 , installed it back in April 2019, install was easy, really fitted our bill, but for the excess urine getting into the bucket.
Occasionally, urine from some women will enter the solids chamber. This is because the women is leaning forward when sitting, and her pelvis tilts back. The solution is for her to sit more upright. Short women may need a stool. You don’t need to do anything else.
Can the 6 month storage period in the container be avoided if the contents of the toilet is emptied directly into a compost bin and left to decompose for 6 months? Don’t really want a bunch of full buckets sitting around. Would rather utilize compost bins if possible.
Yes, that is the preferred method. Use a compost bin, not the little buckets that come with the toilet.
Is there a weight limit ?
Yes. The Separett weight limit is about 250 lbs. The Nature’s Head about 350 lbs.
The urine backed up in the pipe. We’ve had the unit for 5-6 years. This only happens in really cold weather. It eventually drains overnight, but it is preventing us from using it. I put up build up remover in. Still waiting if that will eventually work. I think the blockage must be nearer to the end of the pipe because it does drain and stop. So, it must be sitting in the pipe. I did not install in, and the original person is not around. Help!
Hi! We’re putting the 12v Separett Villa into an outhouse in a woodland setting. So solar efficiency isn’t great and we’re concerned about how long the fan will last between our visits to the forest (could be 3 – 4 weeks). In this instance, are we better to empty the container when we leave or can we simply cover the container with the lid and turn the fan off? Many thanks (great article btw…)
Every installation is a little different, in terms of ventilation, so it’s hard to say. There may be enough natural draw up that pipe to keep everything smelling fresh. I’d experiment. Turn the fan off for a day or two, and see if you start smelling odor. If not, all is good. If you do, Then experiment with the lid. I really doubt that you will return to and odor if you put the lid tightly on the bucket. You could also put a plastic bag over the top and hold it there with a large elastic band. If all this doesn’t work (unlikely) you’ll need to empty the bucket before you leave.
I installed this toilet, and I have to say that finding extra exhaust pipe that matched the supplied fitting and pipe was a nightmare. I had to fabricate a connection to use 3 inch schedule 40 pipe to join the pipes . Should I have to change this, are there any options for a commonly available pipe size and connection system?
There are adapters in the box allowing you to easily transition between the metric pipe that comes with the Separett and standard 3″ schedule 40 PVC. You don’t have to fabricate anything. Sorry this was confusing. I agree that the instructions should be better.
Hello, how long do the Separett Bio Drain tablets last on average? We have four in our family and are having a Separett Villa 9010 installed in our caravan.
A few weeks. You can also use enzyme blocks from a janitorial supply store, which are cheaper. Cut them down to size.
What if a person has loose stools and there tends to be some diarrhea in the sold tray. I read 2where you said some moisture is ok. Another owner said she used a diaper in the bottom of hers was wondering if this may be a solo runny stool in the dry bin or will toilet paper being thrown in absorb loose stools.
A bit of diarrhea should be no problem. A compostable disposable diaper will absorb the excess liquid. Toilet paper will not be if much use.
We have just removed our first bucket from the Villa and after transferring the waste to another bucket to finished composting, the original black bucket smells really bad. We are using the bags and also a diaper in the bottom so what can we do about the smell?
I’ve not heard of that before. Clean the bucket thoroughly with bleach and let it sit in the sun. Try double bagging it. The good news is, it won’t smell once the toilet is closed and the fan is on.
Thank you! I will try the bleach and the sun! Other than that we love our Villa!
Do you have the bags that can be purchased or will just any composting bag work for the container? If you have them how much are they for what quantity?
Any compostable bag will work, as long as it’s big enough to fit the bucket. We have bags but they are a little pricey – $20 for 10 bags. You can get them online much cheaper. Double bag it.
I have small gnat like bugs that are inside the solid container, what is recommended to get rid of them?
Fortunately that is usually an easy problem to solve. First try to eliminate the source of the gnats. If there are no gnats in the house there will be no gnats in the toilet. I realize this can be tough, especially in warmer climates. Screens on the windows help a lot, and try to eliminate gnat sources like bowls of fruit. Clean out the toilet with warm soapy water (don’t spray it, that might ruin the fan), carefully getting everywhere possible. Add a small quantity diatomaceous earth to the bucket. Gnats seem to hate diatomaceous earth. As a last resort in areas with lots of gnats you can put weather stripping on the bathroom door and keep it closed. Moth cakes inside the toilet will of course work but many people are understandably reluctant to use those. People have experimented with natural insecticides, but I have no solid information on the effectiveness of that.
What is the best way to install into an Airstream classic 2017?
Sorry, I’m unfamiliar with that trailer.
Can you give a guesstimate of electrical requirements for the 12 volt fan. I operate all electronics on solar and generally only have storage for about 3-4 sunless days, then need to run a generator. For example how long would one of the small rechargeable 12v dry cell batteries used for portable fish finders lasts running 24/7?
The fan uses about 3 watts on a continuous basis. How long a battery will last, or your solar panel requirements are dependent on many variables and beyond my expertise. Maybe call a solar place?
We are contemplating a composting toilet for a guest house but concerned about cleaning. How do you clean this toilet? Can you use water/moisture? If so, how do you clean and keep moisture from compost container?
You spray the bowl with a spray bottle containing water. Then you wipe clean with a paper towel. Drop the towel into the bowl. The opening is large, and the sides are almost vertical, so the clean up is less than you might think. There is no concern with a small amount of moisture getting in the compost container.
With the Separett, is there a way to connect/divert the urine into an interior holding tank that can be removed and emptied – as with the Nature’s Head – rather than an exterior drain? We are wanting to use this in a warehouse setting where there is not an option for an outside drain due to concrete inside and out.
You can drain it into any holding tank, as long as it flows with gravity.
How do I get to your shop page for dimensions and different models?
The dimensions are on the page for each toilet. To get to the shop page, go to the top of any page and click ‘shop’.
Question I am building a tiny house for one. What is the smallest Separett toilet available?
The Separett Weekend is the smallest toilet. You can see dimensions on my Shop page.
An exhaust fan running 24/7 pulling indoor air through the toilet seems like a huge heating loss. Have you tried using outside air as the source of the ventilation air through the toilet?
When heat loss is a concern people will often install a make up air vent in the bathroom. A low tech solution would be a simple manual vent you could open a crack, and keep the bathroom door closed. There is no air intake on the toilet, and the seat is not airtight. You could install an intake vent, and most, but not all, of the air would then come from outside. However, you’d have to cut a hole in the toilet.
Can the Separett composting toilet go in a wet bathroom? Would i have to cover the lid and sides with plastic?
How wet? There is a metal spring inside, and an electric fan, so it could not be getting water poured over it or anything like that. You don’t want to run a shower over it.