Informational Guide

DIY Composting Toilet: How To Make/Build

Looking to save on bills, help the environment, & use natural processes to recycle waste? A DIY composting toilet is just what you need!

by Caitlin Shaffer

If you’re looking to save on utility bills, reduce the negative impact on the environment, and use a natural process to recycle human waste, then composting toilets may be just the ticket for you. Building these toilets has grown quite popular in recent years though many people are unsure of how to do so. If you want a comprehensive guide, then you're in the right place.

Composting toilets are incredibly useful tools that are configured to collect human waste and convert it into compost. Human waste is covered with dry materials like sawdust, wood ash, and others. This way, you're actually using the waste as a resource, or as "humanure," as so many call it. The humanure can be used in gardens to help fertilize vegetable plants, fruit trees, and more!

There are 2 types of composting toilets: self-contained and central/remote. Let's take a look at each to help you determine which type is right for you.

Self-Contained Homemade Toilet

These types are ideal for small homes, RVs, boats, and even places like cabins. If you’re somewhere on the move or are in a smaller residence, then these are the perfect configuration. No plumbing is required at all, making them economical and great for winter weather. As most have some type of bowl liner under the seat, you can remove it for cleaning at any time you need to.

Central/Remote Homemade Toilet

If you’re looking to install a composting toilet for larger/more permanent residences, then a central or remote toilet may be the optimal choice for you. This type takes solid and liquid waste into a central composting system located somewhere other than right underneath the bowl like the self-contained models have.

For many people, they choose the basement or outside the house as the composting location. As far as looks go, these toilets look quite similar to your traditional toilet.

DIY Composting Toilet

Composting Toilet Components (Plus Considerations When Building)

  • The Compost Chamber
    This is the area where the human waste and composting additives mix together and create decomposition. Usually this is going to be a bucket placed directly under the seat. In central/remote chambers, the toilet seat will sit above a composting reactor which, as we mentioned, is going to be in a basement or outside the home usually.
  • An Exhaust System 
    To let foul odors, heat, gases, etc., escape, you’ll need some kind of exhaust system. This could be a tube leading from the chamber outside the home, complete with a small fan inside the tubing to draw the air in and push it outside.
  • Ventilation
    There’s usually some natural ventilation with compost toilets, but extra ventilation will help dehydrate solid material and eliminate odor. You can create vents or just have a small computer fan inside the tubing.
  • Manage Excess Liquid And Leachate 
    You do want the composting mixture to be moist but never too wet as it can slow oxygen infiltration, which is essential to properly break down waste. Because of this, you may want to add in a urine diverter to collect excess liquid in bottles or a section of designated land.
  • Withdraw The Compost 
    It’s all fine that you're starting a compost pile, but you eventually are going to have to withdraw it and let it sit for a year or so to become a safe and proper "humanure." With self-contained systems, you could just empty out the bucket if you want into a space where you’ll store your larger compost mixes for more extended periods. Afterward, you can simply rinse it out with a high-pressure attachment.
  • Available Space
    First consider the space you have available to place a composting toilet. Do you have the space/circumstances to place a remote/central system? If you decide on a self-contained system, how much room do you have for it? Make sure that you have not only space for the chamber/seat but also an area to store wood chips and a scoop.
  • Tank Capacity
    You should figure out how big of a tank you realistically need and want for your setup. Consider how many people will be using it, as you don’t want to be emptying it out too often as it can be time-consuming.
  • Utility Usage
    How much are you currently spending on utilities, and how much is a regular toilet using in water? This is not only a benefit to you and your pocketbook but to the environment as well.
  • Waste Removal
    How will you feasibly get rid of the waste? If it’s going to be more of a hassle than a benefit, then it may not be for you. However, if you have enough room to store various buckets outdoors and keep the compost piles for long periods, then it’s more than ideal!
  • Odor Removal
    While most composting toilets done right will not and should not smell, there are always exceptions. Will you be able to set yours up to transport foul odors away and outside of your home? If it is a tight, closed space, then you really need to think about if you’ll be using fans and tubing or if you’ll just rely on the natural aeration and odor-masking abilities of the woodchips.
Composting Toilet Components

How to Build a DIY Composting Toilet (Easily & Affordably)

We're going to go ahead and cover exactly how to make a composting toilet. It may sound like a lot to take on, but you'll probably be surprised at just how easy it actually is. Keep in mind there are various types, and you're not locked into just one design. There's something for practically every kind of household! If you're looking for how to make a composting toilet from scratch, then this is the guide for you!

How to Build a Composting Toilet for an RV

Composting toilets for RVs are incredibly useful (have you ever tried unclogging a regular RV toilet?!), and this is a guide on how to make them for RVs, cabin, and other types of homes.

Necessary Supplies

You won’t need much else aside from at least two 5-gallon buckets, wood, a toilet seat, and hardware! Your wood needs to be just slightly taller than your bucket as the bucket will be used for the chamber. If you don't want to use separate pieces of wood, often, you can use a spare corner cabinet instead.

  1. 1
    Saw a hole the same size as the 5-gallon buckets into your top piece of wood/top of the cabinet. Line the toilet seat right over the hole and mark where you need to drill holes to attach the seat.
  2. 2
    Drill holes, and screw the side pieces of wood onto the top piece with the hole cut into it. If you are using a cabinet, this step can be skipped over.
  3. 3
    Attach the toilet seat to the plywood.
  4. 4
    Place a bucket right, so it fits into the hole you cut into the top piece of wood/top of your cabinet.
  5. 5
    Add a few inches of cover material (wood chips, sawdust, etc.). This is also how to make a composting toilet not smell.
  6. 6
    Make sure you have a bucket full of cover material with a scoop next to the toilet. Some setups have a separate container included with a lid over the top!
How To Build A DIY Composting Toilet

Environmental Benefits of a DIY Composting Toilet

  • Save Water And Energy
    Compost toilets use hardly any power and basically zero water, which makes them incredibly environmentally friendly. They require no infrastructure, waste treatment facilities, or septic/plumbing systems. Everything which goes into the toilet chamber is recycled (should you do so).  
  • Better In Areas Where Water Is Scarce 
    Do you live in an area where water is scarce? Then composting toilets will make a huge difference. In fact, one person is capable of using up to 2,336 gallons of water per year just from toilet flushing! You’ll save quite a notable amount on your water bill every month by adding a composting toilet or completely replacing your traditional toilet with one.
  • Waste Acts As A Natural Fertilizer 
    When done correctly, waste created from a composting toilet can be an excellent alternative to the fertilizer you’d buy at a greenhouse/Home Depot.

People Also Ask (FAQs)

Do composting toilets smell bad?

Nope! If done correctly (with the use of cover like sawdust, woodchips, etc.), it shouldn’t smell bad at all! However, if you are concerned, you can always add extra ventilation, fans, tubing, and more.

Where does the waste go in a composting toilet?

It’s placed into compost piles and left to fully develop into humanure.

How often do composting toilets need to be emptied?

Usually, you’ll have to empty them around every 2-3 months. However, this depends on how many people will be using it as well. You can do this by keeping a tray or a liner in the bottom of the composting toilet so you can pull it out and empty it into your compost pile.

Do you need plumbing for a composting toilet?

Nope! No plumbing is necessary with a DIY composting toilet!

What is the disadvantage of composting?

The only real downsides are that yes, you have to do a bit of prep work, and the period of time you have to wait before it can be used as humanure is a bit long (usually around 1 year).

How much does it cost to build a composting toilet?

Super cheap! You could feasibly make one for well under $50!

Are composting toilets gross?

Not at all! This is a natural process, and using a cover really makes any odor disappear. It may take a bit of getting used to, but it’s not as gross as you may think.

Can you pee in a composting toilet?

Yes, you can! However, some people choose to separate the urine by adding a separate container towards the front of the toilet seat. You can also make a DIY urine-diverting composting toilet, should you prefer.

Do composting toilets need electricity?

No, they do not. However, you may choose to use a little computer fan that may use a small amount of electricity.


Conclusion

Now that you know just about everything you could ever need to about composting toilets, can you make your own composting toilet? If you follow our guide, you should have no problems at all and only reap the benefits from these setups!

Caitlin Shaffer has been traveling & working as a content writer & SCUBA dive instructor since 2014. Having lived in Central & South America, Southeast Asia, India, & Australia, Caitlin has had many years of experience with a variety of kitchen, bathroom, plumbing systems & common household products. Other than writing about her plumbing experiences & knowledge, her main passions are yoga, ocean conservation, & sustainable development.

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