Off-Grid Composting Toilet: Everything You Need to Know

Discussing off-grid composting toilets may involve some dirty talk, but it makes sense, given how much waste people produce each year. In fact, the average person produces about 320 Ibs (145 kg) of poop per year. But this is natural and something all people have to be mindful of, especially so if they are self-reliant homesteaders, campers, or preppers.

If planned for and used properly, human waste can be repurposed as compost to fertilize non-edible plants. And if you are looking to become self-sustainable, an off-grid composting toilet is an excellent tool to convert waste into compost efficiently.

So, is it worth all that hype?

Well, composting toilets certainly helps with energy and water conservation. However, they also require considerable maintenance to control the odor and keep the composting process viable. Plus, you need to consider the legalities and logistics of the system as a whole.

What are composting systems all about, and are they the right choice for your off-grid lifestyle? Let’s find out!

What Is an Off-Grid Composting Toilet?

Composting toilets, also known as dry flush toilets, are waterless systems that break down human waste using aerobic bacteria while immobilizing harmful pathogens. Then, the toilets create a by-product (similar to topsoil) that you can use in gardens (non-edible plants only) or dispose of appropriately underground.

This by-product is often smaller than fresh solid waste and thus easier to handle. On average, a composting toilet can break down the waste to around 10-30% of its original volume, provided that the system is running efficiently.

So that’s why it’s called a composting system.

Meanwhile, the “off-grid” part of the name comes from the fact that these systems require little to no water and can run without access to a municipal drainage grid. However, some people also call them biological toilets since the key factor in the process is the anaerobic bacteria.

Although composting is the main principle behind these off-grid toilets, some models rely on evaporation as well.

That’s because these systems mix urine and solid waste in the same container. Then, a fan or a venting system evaporates the excess liquid to leave just enough moisture (around 60%) for the microorganisms to hydrolyze the waste into simpler compounds.

Pros and Cons of Composting Toilets

The idea of keeping waste around for weeks on end might sound unpleasant. Yet, using composting toilets is a growing trend.

In fact, some studies are looking at the possibility of using these dry systems as an alternative to conventional toilets. However, there are some hiccups to overcome first before the system becomes popular in urban settings.

Advantages of a Composting Toilet

From water conservation to composting potential, there are a lot of merits to consider.

It’s Suitable for RVs and Remote Buildings

Composting toilets are a great fit for avid campers. Even if you don’t have access to a clean source of energy, you can still find a suitable composting toilet for your camping setup.

These toilets can also be a lifesaver for those who live off the grid in remote locations with limited or non-existent access to plumbing systems.

It’s Eco-Friendly

Since composting toilets are practically waterless, they can help you cut down on your domestic water consumption.

Plus, many of these toilets create a usable by-product. It’s possible to use the humanure around your ornamental plants.

It Can Handle Toilet Paper as Well

When you’re using a composting toilet, you don’t have to worry about emptying a trash can full of toilet paper every couple of days. Instead, the system composts it with solid waste. Of course, using quick-dissolving (RV or marine) toilet paper can help speed up the process.

Just keep in mind that while toilet paper is okay, the system won’t be able to handle everything you throw into it. For instance, you’ll still need a separate trash bag for menstruation products, wipes, and diapers.

Disadvantages of a Composting Toilet

Despite their advantages, composting toilets are not without flaws.

It Can Be Expensive

The initial costs of installing a composting system are usually higher than connecting a conventional toilet to the grid.

Plus, with careless installation, the system might leech waste. Not only will this smell awful, but it’s also a health hazard.

So, if you don’t have a lot of experience with DIY projects, you can settle for a less complex system or get a professional to tackle the installation for you.

It Requires Regular Maintenance

While municipal facilities handle solid and liquid waste from traditional toilets, dealing with the waste from a composting toilet is, unfortunately, your responsibility.

A properly installed system shouldn’t smell terrible, but emptying the holding tank is still not a pleasant chore.

Some toilets run on more complex systems and are more or less self-sustaining. However, these are usually even more expensive.

It Comes With a Learning Curve

Some composting toilets are better used in a seated position, even for urine. Of course, not everyone will find this convenient.

So, there’s a bit of a learning curve, but you should be able to pick up some tips and tricks along the way.

For instance, some people use the crank (a handle that stirs the solid waste inside the composting chamber) as an indicator of the amount of waste. When the crank is too heavy, the holding tank needs to be emptied.

What to Consider Before Getting an Off-Grid Toilet

At first glance, a composting toilet might not look all that dissimilar to a conventional toilet. They both have the same general design for the seating part, but the internal mechanisms are entirely different, which means that installation and operation are different as well.

You can just install a conventional water toilet in any bathroom connected as long as it’s connected to the grid. You don’t have to keep electricity sources, laws, capacity, or manual draining in mind at all.

On the other hand, installing an off-grid toilet needs some planning ahead.

Here are the main factors to consider:

Local Laws

Some states allow composting toilets, but only if they are NSF-approved. Even then, you might still need to get a permit from your local sanitation department and follow the recommended disposal method.

Other off-grid toilets, like pit privies, aren’t permitted in residential areas with functional grids in states like Florida.

Placement

Composting toilets don’t need a nearby water source.

However, the composting container has to go underneath the toilet. In residential areas, you can place the system a few floors down as long as the chute is straight.

Keep in mind that the chosen spot for a composting toilet has to be around 65-136°F.

Maintenance

Each off-grid toilet system has a different maintenance routine. Generally, you have to be prepared to shovel human waste into a wheelbarrow and daily stirring.

Either way, it’s important to remember that using harsh detergents in the composting container is off the table since it kills aerobic microorganisms.

Frequency

If you’ll only use the off-grid toilet occasionally, any small and simple setup can do the trick.

The challenging part is finding a complex setup with a large capacity for full-time use. Ideally, you want something that’s rated for at least 90 uses. At this rate, you’ll need to empty the container every 3 weeks if two people are using the toilet.

Capacity

A two-barrel composting setup is recommended for one full-time user, and two adults need a three-barrel system. For a family of four, one active barrel and four aging containers will work just fine.

Just keep in mind that the standard barrel size is 55 gallons.

Types of Off-Grid Toilets to Consider

Composting systems are convenient for people who live in remote areas and don’t mind putting some effort into regular maintenance. However, they’re not the only system fit for off-grid living.

From an old-school outhouse to a biogas toilet to a simple bucket toilet, there are a lot of options out there. Depending on the available utilities, usage patterns, and disposal methods, you might prefer one system over the other.

For instance, some require energy sources and running water, while others run on simple operation principles. Similarly, the by-products can vary from regular compost to methane.

It’s hard to say that one of these systems is inherently better than the others—it all boils down to your needs and budget. So, let’s take a closer look at the top six off-grid toilet options to consider and their highlights.

Cartridge Composting Toilet

Cartridge composting toilets come with tanks that you line with plastic bags.

If you don’t mind splurging a bit, get a self-sealable model that collects the waste in a bag. When the bag is full, you just press a button to seal the bag automatically. This way, you don’t have to collect the waste yourself.

All you have to do is throw the old bag away and add a new one to the container. It’s still possible to use the humanure from the cartridge. You just need to let it cure in a compost pile for 2 months or so.

Incinerator Toilet

The incinerator toilet is also a waterless standalone system. However, unlike the composting model, it doesn’t leave behind a usable by-product. Instead, the system burns up solid and liquid waste into ash and vapor.

The main drawback is that the incinerator toilet needs a reliable energy source. This source could be electricity or propane.

The fire doesn’t run continuously, though. The system collects waste in tanks and then burns it all at once during an incineration cycle. Usually, the toilet will be good to go for 40-60 uses between cycles.

Portable Toilet

Portable toilets collect solid waste in removable tanks with recyclable bags. The body itself is often made of polypropylene to keep the system lightweight and easy to move around. That’s why they’re particularly popular for RVs and boats.

Some of the portable toilets out there are waterless, while others have a tank with a pump for flushing. Either way, urine separators are common features. You’ll also find vents that prevent gas accumulation inside the tank.

That said, some models run on 12-volt venting fans. If you want something completely off-grid, get a toilet that uses a battery or solar panels instead of an AC supply.

Home Biogas – Bio Toilet

We like to think of the biogas system as a step up from regular composting toilets. Instead of turning the solid waste into compost, it produces methane through anaerobic digestion. Then, you can use this gas to power cooking appliances.

Of course, you don’t have to set up the stovetop and the toilet in the same space—they can be up to 23 feet away.

However, the installation can be rather complex since the kit includes gas pipes, filters, and a digester. Plus, you need to keep the digester under sunlight.

You’ll also need a running water supply for each 0.3-gallon flush.

Outhouse Toilet

Outhouses are a common option for traditional off-grid cabins since they’re low maintenance. You just dig a hole in the ground and set up an outdoor potty structure above it. As long as the location is downwind and far from water sources, you’ll be good to go.

To control the unpleasant odor, some people use lime, sawdust, or peat moss. Other than that, you won’t need to flush or drain.

Yet, outhouses are best used as a short-term solution. Otherwise, you’ll need to relocate the structure after a few years.

Separating Compost Toilet

The urine-diverting system is like a regular composting toilet with a minor tweak; it automatically separates liquids from solid waste.

With regular internal composting toilets, exhaust fans or vents dry out the excess moisture, so you don’t have to deal with urine. On the other hand, separating models collect urine in a tank that you have to drain or use as a fertilizer.

However, being seated while using these models is a must since the toilet collects urine through a pipe in the front.

Summary

Waterless compost toilets look a lot like conventional toilets, but they have a bottom container with aerobic bacteria that turns solid waste into usable manure. Some models mix urine into the manure, while others collect it in a separate tank.

Overall, these systems are a great fit for people who live off-grid and are looking for a sustainable source of compost for ornamental plants.

If you’ve never tried an off-grid toilet before, using a composting toilet will definitely be a step out of your comfort zone. After all, you’ll need to handle humanure and maybe even empty urine tanks, depending on the chosen model.

However, it can be well worth the effort since it conserves water and energy. Plus, it’s one of the few valid options for someone who doesn’t have access to a plumbing system!

Off-Grid Composting Toilet: Everything You Need to Know

What Is an Off-Grid Composting Toilet?