DIY Composting Toilet

While we are looking for land to build our homestead, we are checking off essential skills we need before building our 16'x20' cabin. One of those skills is woodworking. And since Santa brought my husband a boat load of new tools, we decided we would start building items for the interior of our tiny house.

If you are thinking of building your own composting toilet, you have come to the right place! With my husband's help, we have created two different views of the cut list, complete instructions and pictures along the way to create a beautiful composting toilet like ours! So grab your coffee, and settle in!

When building our composting toilet, I had a few things to keep in mind when we created this design. I wanted our toilet to be very classy, clean lines and stylish even. I wanted it to look like a traditional toilet so we didn't frighten or intimidate visiting family and friends. I think we pulled it off!

Composting Toilet Cut List:

Sheet of 3/4" Maple Plywood

18" x 7 3/4" Tank Lid
18" x 17 1/4" Back Rest/Tank Front
18" x 7 3/4" Rear Seat/Tank Bottom
18" x 18 1/2" Front Seat
14" x 63 3/4" Bowl
16" x 32" Back
7" x 17 1/4" Tank Side
7" x 17 1/4" Tank Side
Crescent cut to size to nestle bucket.

2" x 3"

16" two pieces Tank Horizontal Support
11" two pieces Tank Vertical Support
13 1/4" two or three pieces Seat Support

Additional Items Needed

Handle for tank
Toilet seat
4 hinges
5 gallon bucket

Putting Your Composting Toilet Together:

First you will want to assemble the Tank Support made from 2" x 3". Using all your 16" and 11" Tank Support pieces, screw together a box that is 16"wide.

Once all you have put together your tank support, the next step involves several more cuts to create a flexible piece of wood using the Kerf method. Try this method on a scrap piece of the same plywood to ensure you don't cut completely through. This was our first time using the Kerf method, and it worked excellent! Take your Bowl sheet, find the center, and cut nearly to the laminated sheet. Each cut should be placed an inch apart for a total of 18 cuts on each side of the middle or 37 cuts all together.

Lay your Bowl Piece on a flat surface and lather with wood glue. Using clamps, gently bend your Bowl Piece, as shown in the picture below. Insert the Back Piece between the ends of your Bowl Piece and secure with clamps. Put your Tank Support box you just made five inches in front of the Back Piece (not shown). The Tank Support also helps you to keep the toilet a certain shape. Using pocket holes, screw it together. We used a Kreg tool to make this easier.

Next, we screwed in the Rear Seat/Tank Bottom on top of the support square then added the Tank Side Pieces and Back Rest/Tank Front together using pocket holes. We attached the Tank Lid with two hinges and added a fancy handle to class it up! This little box it where we will keep our shavings for covering our excrement. 

Next, we placed our toilet on top of plywood and traced the curve to create our crescent to nestle the bucket and help hold it in the right place. We made the crescent, or half circle, 3 inches wide and screwed it to our two Seat Support 2" x 3". (See photo below)

Next we put together the seat! We created a slight over hang using a square and pen to trace the outside of the Bowl Piece adding a half inch around the front of the bowl.

To make the hole in the wooden seat, we placed the bucket inside the toilet, and closed the seat until it touched the top of the bucket and marked it with a pencil, this is how we knew where to put the hole. After, we removed the seat, set it up side down and traced the bucket starting where we marked it. Start cutting the hole by drilling a hole and inserting a jig-saw to cut it out. Attach the wooden seat with hinges and add a plastic toilet seat for comfort.

Don't forget to sand the edges of the wooden seat hah! Your composting toilet is now ready to be used. You may have noticed our design doesn't include a urine diverter. This is because we only intend to use the composting toilet inside our cabin or stormy days, middle of the night or when it is raining cats and dogs.

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  1. Great post! I will be sharing this with the hubs. Quick question... what is a urine diverter?

    1. Thank you! A urine diverter is a funnel which diverts urine away from the humanure compost. Too much urine will make the compost unusable, very smelly and will stop the compost from breaking down like it should.
      Thanks for reading!

  2. I like your curved design. There is no need to separate urine from the solids and when the toilet contents are added to a humanure compost bay the urine will be of added benefit as it is high in nitrogen. If there are any smells coming from the toilet then the cover material (sawdust, etc) is not being used in enough quantity or is not fine enough (allowing too much air in). Worth remembering that the toilet itself is not a composting unit.... composting is what happens when the bin is emptied into a bay (outdoors)/ with hay/straw/ food scraps/ dead animals, etc.

    1. Thank you! And, you're absolutely right! Thanks for reading!