Going tiny often means going off-grid or, at the very least, being portable. When designing your tiny home, this means you’ll have to consider how you’re handling the systems of your home, including water storage and black and gray water. Choosing the right toilet system for you can make the other decisions easier.
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A standard water toilet requires hookup to a septic system or sewer. It’s not a portable alternative, but can be easily obtained for a reasonable price at any DIY center. If you choose this option, you’ll need access to running water for filling and emptying the tank. If you’re using a water pump, this will also increase your electric bill. You’ll then need to consider how you’re going to handle the black water disposal. This is still the standard for home-building, however. If your tiny home will be in an urban setting on a foundation, this is still the easiest option, especially while dealing with housing authorities.
A Tiger Toilet is not a widely known option and is still in experimental stages in India, Uganda, and Myanmar for rural, peri-urban, and displaced persons camps. It uses a pour flush toilet, but the contents of the toilet are flushed into a vermiculture tank. Basically, there is a large drainage field for liquid disposal while tiger worms (similar to red worms) take care of the solids. It’s being tested in areas where sanitation is a problem, but is a potential solution to septic tanks which are more costly and require emptying and removal to an offsite location.
Extremely Low Flow Toilets
These toilets use one gallon or just over a gallon of water to flush. They still require some sort of waste storage container. If you’re using a camper blackwater tank, it will need to be emptied. This is a green option for locations with limited access to water or tiny houses on wheels in which a black water tank is an option.
The Thetford 35831 Electra Magic Toilet might be the most interesting version of this. It’s a recirculating toilet that holds up to seven gallons of water, recirculating three gallons of treated water. It does require 12v DC for the circulating pump. While it doesn’t strictly use one gallon of water, it makes the list for reusing water. No information is given for how many flushes are available before you have to dump the three gallons and start again. Uses one cup of Aqua Chem deoderant on setup and after each emptying. Can be hooked to your black water tank or as a stand-alone that is drained directly into a sewer tank.
The Eago TB336 uses only 1.28 gallons of water to flush and fits nicely into more modern home decor. It does seem to require the assistance of a plumber to install as some parts will have to be relocated. Reviewers have stated that their plumber charged them extra for this since it was more time-consuming to install.
Saniflo 023 SANICOMPACT 48 is completely unique in that it macerates, or chews up, waste before sending it into the tank. It uses only one gallon of water for flushing and allows the connection of a sink, which is perfect since it doesn’t have a tank. The flushing mechanism is electric and will require 110-115 volts. It uses 7.2 amps during its 10-15 second flush. Reviewers praise it as one of the smallest toilet options on the list, so perfect for a tight space where a normal toilet will not fit. In addition, because it grinds up the contents, you only need a one to one and a half inch pipe for disposal to your tank.
An RV toilet is notoriously low-flow, but usually involves some chemicals. The Aqua-Magic V boasts the need for even less water if you attach a hand sprayer to it, which can also be used to wash your hands after going. It’s specifically designed so that every bit of water you do use rinses the entire bowl before going down. Of course, you will still need some sort of holding tank for this type of toilet. At only 9.4 pounds overall, it’s a very light alternative, as well.
Cassette toilets are more widely known as camp toilets or a porti-potty. Where I come from, a porti-potty is the big blue or green box found on construction sites or at an outdoor concert or fair. Cassette Toilets are nice because they are versatile in placement and storage, very portable, and can be emptied in any toilet, including a public restroom or wayside. Disadvantages include the potential for an awful smell when emptying and the weight of a full five gallon storage tank.
The Camco Standard Portable Toilet is the most popular in this category at the time of this writing. It offers options of a smaller, but lighter, 2.6 gallon holding tank over the heavier, but longer lasting 5.3 gallon tank. It also features a Premium or Standard package. The Premium package is slightly larger, has a larger flush tank, and a better flush action system. Reviewers state that, if you get the tank started with some clean water and use the chem packs that come with the unit, it will be completely odor-free, even when emptying. Van dwellers often use this model because they can hide it away under a bed or storage cabinet.
Porta Potti Curve by Thetford is a more stylish option with slightly larger fresh water and holding tanks. It features an integrated toilet paper holder and weighs one pound less empty than the Camco Premium version above. One review I saw did mention that they loved everything about this toilet until it came to empty it. The smell, they said, was unbearable.
Incinerating toilets use electricity to create heat that burns all of your waste. From there, you simply remove the ash tray. They are vented to the outside, so there is minimal smell, although you may get a smoky smell from the incineration process.
Incinolet seems to be the most well-known of the incinerating toilets. It uses only one kwh of electricity per cycle, but a complete cycle is an hour and a half to an hour, 45 minutes. It requires a dedicated 20 amp breaker. You can use it while a cycle is in progress. It can be vented to the outside either through a wall or chimney. A paper liner is required for every use and the cycle should be run with every use.
The ECOJOHN SR5 model is adaptable for use in tiny homes on water, wheels, or land. It requires a seven foot minimum chimney and doesn’t offer a wall option. You have the option of propane, natural gas, or diesel alongside electric options of 12v DC, 120v AC, or 240v AC. To be clear, you have to use one of the three gas options and one of the three electric options. It requires both gas and electric. The Incinolet only works on electricity, but doesn’t offer battery or solar options. The ECOJOHN SR5 runs for five to ten minutes for a liquid cycle and thirty-five to forty mintues for the long cycle. The electricity is required to run the auger and start the burn cycle. Everything else is done via gas.
ECOJOHN also offers a remote option in the form of the WC Series. These hook up to an existing holding tank, use a Macerator Pump to grind up the waste, and then incinerate it after the holding tank. The WC series can be hooked up to regular and low-flush toilet systems. This can be a good option where a failing sewerage solution is a problem, such as a condemned septic system.
The Sanitizer uses air flow and short bursts of heat to evaporate liquids and to dry and sanitize solids. The contents of the tray from completed cycles is thrown in the garbage in the same way that you would dispose of diapers or kitty litter. It works off regular household current or can be used with solar power or generator. The blower motor runs 24/7 on this unit to maintain air flow underneath which is vital to the evaporative process. The heater, when on, is not warm enough to burn paper. This is evaporative, not incinerating.
Laveo’s Dry Flush toilet comes in at less than half the price of many other options on this list and might be the most unique of all. A double bagging system includes an outer bag and a cartridge of foil-type bag to collect waste. When you “flush,” the toilet twists, squeezing out any air, and then vacuum seals your deposit, dropping it into the base of the toilet inside the outer bag. When the cartridge is used up, you slip it into the outer bag and pull the outer bag out just like emptying a garbage can. Everything is sealed inside and safe to deposit in the dumpster. No smell, no bad visuals, nothing. You will have to keep buying cartridges for the toilet, which could pose a problem if the concept never takes off and they become difficult to find. Each cartridge is good for 15-17 flushes. Runs on a 12V battery with a battery charger.
No tiny home discussion would be complete without coverage of the various composting toilet options. Whether it’s a built-in system or a bucket toilet, composting toilets are, by far, the most commonly used by builders and DIY’ers alike.
Nature’s Head is one of the more commonly seen toilets in tiny home tours. This could be partially related to price or promotions since many features and benefits are similar among the various brands, but it should also be noted that user reviews are higher in general. This model requires cranking, but also comes with an exhaust fan that should be run on a regular basis using 12v electricity. The vent hose is also included but, at five feet in length may be too short for your needs , so verify that upfront. Uses peat moss and coir core for the composting process. This is a diverting toilet; the liquid container will need to be emptied frequently.
The self-contained model is one of the heavier options on the list, weighing in at a full 100 pounds. It comes with the venting kit and uses electricity for the fan with an option to use either AC or DC but not both. I’m not going to lie; the reviews on this model are terrible. The drainage for the urine is too small and seems to overflow on a regular basis. Reviewers complain that it is cheaply made and that it doesn’t compost well so that cleaning it is a nasty business. This was disappoint for me since the Sun-Mar was the recommended off-grid toilet by Lehman’s Catalog, a name I trust, back in the early 2000’s. It’s sad to see the brand fall like this.
The Envirolet SmartFlush is a little different in that it’s both a vacuum flush and a composting toilet in one. What this means for you is that it will whisk your waste up to 70 feet away and can go up 12 feet. The ability to travel upwards means that you can use this toilet in a basement. It does use 0.2 liters of water for every flush (roughly seven ounces). Envirolet boasts that it’s plug & play so that it’s almost no work to set up.
The BioLet 25 brags that it is the first fully automatic composting toilet. It’s completely waterless, but uses 65W of power for its thermostat, fan, automatic mixer and double heaters. It can be installed in about two hours by the average handyman, according to the website.
For something a little more off-grid friendly, they do offer the BioLet Separating Toilet 30NE. This one is non-electric and waterless per advertising, but a 12v DC fan can be added to its ventilation system. It separates the liquids and solids and uses the provided drainage tube to run the liquids off into a drainage field, increasing the overall usage capacity slightly. Additional compost bins can be purchased to increase the system capacity. They also offer the larger Biolet 65 if you have more than three full-time people using the toilet. Three full-time household members seems to be standard for most composting toilet systems.
Like Nature’s Head, the Air Head was specifically developed with boats in mind. And, Air Head compares itself to Nature’s Head while making some pretty compelling arguments. It advertises that its round shape and round diversion compartments make it easier to place in the smallest of places and easier to clean. The diverter container comes straight out from the base making it so that you don’t have to lift the seat off of the solids containment to remove it. This was, indeed, a complaint that some reviewers had for the Nature’s Head since opening the solids compartment let odors escape. Air Head points out that an added benefit to this is that, since you don’t need room to tip the top back, it can be installed closer to a wall. Finally, the liquid container is less opaque so that you can see liquid levels which is great if you’re having a party with a little too many liquids involved. Because it looks and flushes similar to a standard water toilet, there is a minimal learning curve for your guests. In lieu of an electric fan, Air Head recommends the installation of a solar vent fan.
I chose a bucket toilet for my own tiny home because it fit my budget and my philosophy on gardening and nature. In the Humanure movement, one of the virtues of composting toilets over water flush toilets is that you don’t waste clean water flushing away excrement. In areas affected by drought, this seems exceptionally wasteful. Beyond that, composting toilets return nutrients to the earth.
I’ve already sung the praises of my bucket toilet. I love mine. I told you how to build one and how to have one with almost no effort at all. But, just for the sake of being comprehensive, a quick recap: Obtain a five gallon bucket. For seating, you may choose the Luggable Loo, which is a seat and bucket together. You could use a bedside commode and place your bucket underneath it. Like me, you could build a box around your toilet. If you’re truely like me, you could decorate that box so it looks like something else.
Most composting toilets use some sort of separating system to keep liquids and solids from mixing. There are two main reasons for this: 1) You get stronger odors when they mix and 2) the urine is filled with nitrogen. If it is diluted with water, it can be used immediately as fertilizer for watering your plants. It’s sterile, so there is no need for concern there. I chose not to divert. I have no problems with odors and nitrogen is a great way to make your pile hotter which helps the pile break down faster. In addition, the liquid compost that comes out of your bin is still a great fertilizer.
The Humanure Handbook takes a deep dive into bucket toilets and compost bins. It’s recommended reading for anyone considering a bucket toilet system. You can also visit their website for more information.
To make compost faster, try the Solar Assisted Compost Pile.