Off-grid living has become a lot more comfortable now than it was a few decades, or even a few years, ago. Not only do we have solar power and generators, we can also go potty in the comfort of our homes – without having to trek to the outhouse. If you have no septic or sewer system to hook to, even in rocky soil that won’t allow for an outhouse pit, even in an RV or on a boat, a composting toilet can make life easier when “answering the call of nature.”
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What is a composting toilet?
A composting toilet is a type of toilet that, rather than being attached to a sewer or septic system, uses little or no water to turn solid waste into a soil-like substance. Aerobic bacteria break down the waste into a mixture that can be disposed of in a trash bin, by adding it to a compost pile for finishing, or buried.
Why would you want one?
Composting toilets are ideal not only for boats and RVs, they are excellent alternatives to outhouses. Not having to go outside on a winter’s night to potty is most definitely a plus (been there, done that, no thanks). Some areas are simply too rocky to allow digging a hole big enough for an outhouse. Some areas are too close to bodies of water to allow for either a septic tank or an outhouse. (And nobody likes having the toilet-seat-on-a-bucket sitting in the corner of their cabin…) RV’ers and boat dwellers can avoid having to empty the blackwater tank by using a composting toilet to avoid that nasty routine.
These toilets are well-suited for conditions where water usage must be kept to a minimum, such as in dry cabins. Although these toilets are initially expensive, when you consider that they eliminate the need for a septic tank and leach field, the cost begins to be much more competitive. A composting toilet just might be the sanitary, low-odor solution you need.
How do you use one?
You’ll need a couple of brackets to attach the toilet to your floor, and a power supply to run the vent fan. The fan is small, like the one in a computer. You’ll also need to drill a hole for the vent hose or vent pipe to run though, if your bathroom doesn’t already have some way to get the hose to the outdoors. The vent hose and fan assembly not only keeps odors down, it also helps evaporate water from the solid waste, so it’s an important feature of the toilet.
Prep the solids tank by rehydrating some sphagnum peat moss or coconut coir (recommended) from the garden supply store with enough water so that it looks similar to regular soil. Imagine what a new bag of potting soil looks like when you first open it – that’s what you’re going for. You can also buy “PooPoo Pucks” made of compressed coconut coir, which are more convenient than bags from the garden center. Follow the instructions in your manual for how much of the moss or coir to use in the tank – usually just enough to reach the bottom of the mixing bar that will be used to stir the waste and organic material together when you crank the handle – and assemble the toilet. Place the liquids tank on the front of the toilet and affix the seat assembly on top, using the sliding hinge. Lock the side tabs, and you’re (ahem) good to go.
When you need to urinate, make sure the trap door in the bottom of the toilet bowl is closed. The pee will run towards the front of the toilet bowl where there are drainage holes for the pee to go. (Guys, this is best done while sitting down.) Spritz the bowl with water from a spray bottle to rinse away any remaining drips.
When you need to poop, open the trap door using the lever on the side of the toilet, and poop through the hole. Spray the bowl with a little water if there is any residue that needs rinsing out. When you’re done, turn the handle on the side of the toilet a few times to mix the composting material with the waste. That’s all there is to it.
Toilet tissue can be placed in the toilet, or (preferably) be thrown away in a trash can. While any type of toilet paper can be used, single-ply paper breaks down quicker than thick, multi-ply paper. Tampons and menstrual pads should not be placed in the toilet, as they take far too long to compost.
Because the urine and the feces are kept in separate tanks, you don’t get that familiar sewage smell that is so often found in outhouses and latrines. The small amount of odor that does occur is handled through the little electric or battery-operated fan that directs air through the composting bin and out of the house through the vent hose.
Composting toilets can be used in cold temperatures, although it is best to keep the urine tank emptied, especially if you’re going to be away. Composting takes place in 55 degree weather or warmer, so if you’re using your toilet in a room that will be cooler than that, you may need to add a heat source, or your compost will be dormant until heated up again.
What does the waste smell like? Some people say they don’t notice an odor at all, while most others describe it as a slightly earthy smell.
How do you empty one?
Most areas allow you to empty the urine container directly on the ground, but please use common sense. Don’t empty it where other people are, or on ornamental plants that need special care, or on someone else’s property. If you’re traveling, you might want to stop at a public toilet facility to empty your liquids there. If you’re on your own property, you may want to dilute the urine and use it to water your trees or non-edible plants (don’t use full-strength urine as the salt levels can harm plants). Pouring the urine container out on a dirt road is a good idea, as nobody wants plants growing in the middle of their dirt road anyway. Choose a different place to empty the urine each time to prevent buildup of pee smell or harming the soil nutrients. Speaking of the smell, remember that pee smells like pee. The composting toilet isn’t doing anything to break down your urine, so don’t be surprised that it’s just a bucket of pee.
Tilt the seat assembly up so that you can remove the urine tank, and take it to where you’re disposing of the liquid, dump it out, rinse it, and put it back. You’ll want to empty the liquids tank when it is about 3/4 full.
Now for the solids… This is where people get curious but don’t really want to ask. You might be surprised to learn that what you have in your solids tank isn’t very poopy. Depending on how long you’ve allowed the solids to sit in the tank, you might have some recognizable poop in there, or you might not. The solid waste isn’t technically fully composted, so don’t think you can just take it out to your garden. To be fully composted, the poop would need several more months to break down all the way, so dispose of it in a landfill (yes, this is perfectly fine and legal) or bury it. The tank is designed so that a 13-gallon sized kitchen trash bag can fit over the top of it. You can place the opening of the trash bag over the opening in the tank, turn it upside down and tap the bottom of the tank to make sure everything falls into the bag, and then throw the bag in the garbage. (Bonus points for using a composting bag for this job, because after all, you are trying to compost.)
Empty the solids tank every 60-80 uses, or approximately every three weeks for two people using it full time. Additional people will mean emptying it more often, fewer people or fewer days per week mean you might empty it less often.
Refill the solids tank with rehydrated coir or moss, reassemble the toilet, and you’re all done.
Are there downsides?
Yes, there are. While the smell of the solids is often described as “earthy”, and some people say they don’t smell anything much (if at all), other people say it smells too much of poop, especially when emptying the liquids tank. To empty the liquids tank, you must tip up the seat a few inches and that can let some smell out. The vent hose that comes with the toilet is not long enough for most applications and you might need to buy a longer one to keep the smells venting outside.
If the base is very full, it can be heavy to empty. It can sometimes be a two-person job. It’s recommended by users that you take the entire thing outside from time to time and hose it down, and clean it with bleach.
Take care not to let the urine container get more than 3/4 full, or you risk unpleasant spills.
Some women may have to practice getting the urine to flow into the proper drainage holes. People who pee and poop at the same time might have difficulty also, as urine should not be drained into the solids tank, or you will have smells.
Composting toilets are not cheap. You’ll have to weigh your options to see if spending the money is worthwhile in your situation.
The best composting toilet
The Nature’s Head Dry Composting Toilet is far and away the favorite of composting toilet users, not only for the price, but for the durability and ease of use.
This toilet is available with a crank handle or a space-saving “spider” handle for when your toilet area is a little snug. The elongated seat is not only comfortable, but is molded onto the base for easy cleaning, and isn’t going to give you a cold bottom in the winter.
Developed by long-time mariners and designed for marine safety, this toilet features all stainless hardware for rugged use. The rear of the base is angled, specifically for installation on boats, but works just as well in a cabin or RV.
At roughly half the price of its nearest competitor, the Sun Mar Excel, (pictured below), this toilet is a really good value. Nature’s Head stands behind their product with a five year limited warranty.
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