Make a Twin Bucket Toilet

October 11, 2011

How to Make and Use the Christchurch Twin No-Mix Bucket Emergency Toilet

What do you need?

  • 2 to 4 plastic buckets (5 or 6 gal. size)
  • Lids for buckets
  • A toilet seat
  • Carbon material: 1 or 2 gal. plastic bags of sawdust, shredded paper, pulverized dry leaves or peatmoss.

Supermarkets and bakeries often will give you used buckets for free though they may lack lids.  Lids and buckets are sold at hardware stories and online. At least one lid should have a good seal. Buckets are useful for storing other emergency supplies.   Toilet seats that fit buckets are available at camping stores or on line. You can also adapt smaller ordinary seats to fit buckets.  Your emergency supplies should also include hygiene items: toilet paper, hand sanitizer, soap, sanitary napkins, plastic collection bags of various sizes and this instruction sheet.


How do you use the toilet?

  1. Mark the twin buckets “pee” and “poo” (or #1 and #2 or urine and feces, or yellow and brown, etc).
  2. Set them up in a private space. The seat can be moved from one to the other.
  3. Scratch your head and decide if you need to use the pee bucket or the poo bucket.
  4. Try not to pee in the poo bucket. This is really important but it is understandable that this isnʼt always possible. The pee is the component that produces the bad smell in toilets that mix.
  5. After using the pee bucket remove the seat and cover with a lid that closes well.
  6. After using the poo bucket, sprinkle about a half cup of the carbon material so that it completely covers the surface of the poo. This will eliminate odors and ensure flies don’t make themselves at home.
  7. Toilet paper is just fine for the poo bucket but not for the pee bucket.
  8. Put the toilet seat back down ensuring it’s not airtight. Give your poo some air and it will dry out and reduce in volume.

The Christchurch Twin No-Mix Toilet

Remember that in an emergency people are vulnerable and scared.  If your flush toilet doesn’t work and the sewers are down, folks in your household will appreciate the comfort, hygiene and safety that come with this simple twin toilet.

What do you do when buckets fill up?

The really great feature of the Christchurch Twin Bucket is that it is No-Mix. It separates pee and poo, makes each of them easier to handle and almost completely eliminates odor.

A day’s worth of pee has almost 10 times the volume of poo. So the pee bucket will fill up a lot faster.  The volume of pee is why  a single bucket camp toilet fills up quickly and the mix is a mess to deal with.  The great thing about pee is that it’s clean (unless someone is sick) and getting rid of it is not difficult.  If you have extra buckets and lids, you can store it until it can be put in the soil (6 to 8 inches below the surface) or added to a compost pile.  In a real emergency you can dump urine in a street drain or the river, although a wooded area is preferable. What’s special about the Twin, it that it works even for high-rise apartment dwellers.

It’s the poo bucket that contains most of the pathogens. But the great thing about poo is that it doesn’t take up much space.   Left to dry in a bucket with some carbon material, poo simply decomposes into compost.  In a small household it will take a couple of weeks for the poo bucket to fill so just leave it be and give it some air. Poo is manageable, although there will still be pathogens.

Note: Compost that is safe to reuse on gardens requires extra work.  At the New Zealand team explains how to safely use urine and composted poo as fertilizers for crops.  On this site see sections on Ecological Sanitation.

Our Mission Through education and advocacy, PHLUSH helps local governments and citizen groups to provide equitable public restroom availability and to prepare for a pipe-breaking seismic event with appropriate ecological toilet systems.

Our Vision Toilet availability is a human right and well-designed sanitation systems restore health to our cities, our waters and our soils.

Public Hygiene Lets Us Stay Human (PHLUSH) was founded in Portland, Oregon and today collaborates with groups across North America.

PHLUSH is a member of the World Toilet Organization and a partner in the Sustainable Sanitation Alliance.

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