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DIY Composting Toilet for a Van: How to Build One

How to build a DIY composting toilet for a van: separating liquids, a solids bucket, a carbon cover like coco coir, venting, emptying rules and when to buy one.

By Van Build Gear ReviewPublished 2 min readHow we research
A wooden box toilet with a seat in a van

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A DIY van toilet is a box with a seat, a funnel that sends liquids to a separate jug, a solids bucket covered after each use with a carbon material such as coco coir, and ideally a small vent fan. That follows the EPA's description of composting toilets: unsaturated, aerobic conditions with a carbon additive. It saves money; a commercial unit saves time and has a warranty.

What you need

  • A box or cabinet that fits your space, with a hinged seat.
  • A urine diverter funnel and a sealed liquids jug.
  • A solids bucket with a lid.
  • A carbon cover: Coco Bliss coir bricks or LEIFIDE coir disks.
  • Optional: a small 12V fan vented outside.

How to run it

  1. Keep liquids and solids apart; wet solids are what smell.
  2. Cover solids after each use. The EPA suggests adding bulking material at least every other day when a system is used daily.
  3. Empty liquids often and solids before the bucket is full.
  4. Dispose of everything under state and local rules, which the EPA says apply to the end product.

DIY or buy

DIYCommercial
CostLowestHigher
LiquidsYour jug2.2 gal bottle (Nature's Head)
FanOptional, your wiringBuilt in, 0.07 A (Nature's Head)
WarrantyNone5 years (Nature's Head)

A small commercial unit like the Trelino Evo S or OGO Nomad is a middle ground. Full picks: best composting toilets.

Trelino Evo SCheck price on Amazon

Coir

Nature's Head sells ground coconut husk as its composting medium. Compare options in best coco coir for composting toilets.

Frequently asked questions

How do you make a composting toilet for a van?

Build a box with a seat, divert liquids to a separate jug, put solids in a lidded bucket and cover them with coco coir after each use.

Do you have to separate urine in a composting toilet?

Separating it keeps solids dry, which is how commercial units like Nature's Head and Trelino control odor.

What do you put in a DIY composting toilet?

A carbon cover such as coco coir. The EPA lists sawdust, leaves and chopped straw as other bulking materials.

Is a DIY composting toilet legal?

Rules on disposal vary. The EPA says the end product must be handled under state and local regulations, so check before emptying.

How often do you empty a bucket toilet?

It depends on use and bucket size; empty liquids often and solids before the bucket is full.

Sources

  1. Water Efficiency Technology Fact Sheet: Composting Toilets (EPA 832-F-99-066), U.S. Environmental Protection Agency
  2. Nature's Head Composting Toilet, Nature's Head

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