Composting toilets: Dry toilets that make soil, not sewage · Alt Ordo Systems Guide
A composting toilet is a toilet with no water and no sewer. You cover what you leave with a dry, carbon-rich material, keep air moving, and move the contents to a compost bay where they become soil over about a year. Done well, there is no sewage smell, no septic tank and no flush water. The toilet is the easy part. The real system is the bay out back, and the habit of tending it.
This guide helps you choose, size, install and run a dry toilet for a tiny home, cabin or bathhouse, build the compost bays that finish the job, and know what the finished compost is safe to feed.
What's inside. 17 pages in 9 chapters (At a glance, Where it works, How it works, Size it, Parts and cost, Set it up, Run it, Rules and permits, How it connects), then the sources and a notes page. 7 numbered figures drawn for this guide. You also get a worked example with a fill-in worksheet, 8 numbered steps, a year-round calendar, and a troubleshooting table.
Three builds, costed line by line (typical US prices, October 2026):
- Bare-bones: $90–$110
- Standard: $1,010–$1,060
- Comfortable: $2,800–$5,680
Sourced and fact-checked. Facts and figures are cited to the 20 sources listed at the back, and the whole guide was fact-checked before release. General guidance, not engineering advice: your county and a qualified pro have the last word on your site.
Pairs with other Alt Ordo Systems Guides: Composting; Food forests; Portable power stations. For your county's permits and rules, see our county and state guides.
Instant PDF download. After checkout you get a download link by email. Letter-size pages, made to read on screen or print at home.