Vivid Ready

Two buckets, sawdust, and a compost heap you do not touch for a year. Simple, odourless when done right, and the one number that must not be softened is the curing time.

When the mains fails, the toilet is the first thing people discover they cannot improvise. A flush needs 6 to 9 litres of water each time, and a household producing waste with nowhere to put it becomes a disease problem within days.

A twin-bucket composting toilet solves it with no water, no plumbing and no power, and it can run indoors indefinitely without smelling.

Why this rather than a latrine

	Bucket system	Dug latrine
Water needed	None	None
Indoors?	Yes	No
Winter	Fine	Miserable and often frozen
Effort	Emptying a bucket	Digging
Ground needed	None	Suitable ground, well away from water
Output	Compost, after a year	Buried, wasted
Best for	A household staying put	Short stays, camps, no container

For a household bugging in, the bucket wins on almost every count, and the decisive one in a British winter is that it works indoors. A latrine at the bottom of the garden in February, in the dark, in the rain, gets used less than it should, and that is how people end up doing something worse.

The system

What you need

Item	Notes
Two 20 litre buckets	One in use, one ready. More is better
A wooden box or seat frame the bucket sits inside	So it looks and feels like a toilet
A toilet seat	Ordinary, screwed to the box
A lid for each bucket	For carrying
Cover material, in quantity	Sawdust, see below. This is the important part
A scoop	Kept beside the toilet
A compost bay outdoors	Two if possible

Urine and faeces go in the same bucket. Separating them is a common refinement and it is not necessary; the mixed material composts well and the cover material handles the moisture. Keeping it simple matters more than optimising it.

Cover material is the whole trick

Good cover material, best first:

Sawdust, untreated, from a sawmill or joinery. The standard, and often free. Not from treated timber.
Wood shavings, though coarser and less absorbent than sawdust.
Peat-free compost or coir.
Dry shredded leaves, collected in autumn and kept dry.
Shredded paper and cardboard, which work and are less absorbent.
Dry grass clippings, straw, chopped bracken.
Wood ash, sparingly, mixed with something else. Alone it is too alkaline and slows composting.

Using it

Put a few centimetres of cover material in the bottom of a fresh bucket.
Use it normally. Paper goes in too.
Cover completely after every use, including urine. A scoop or two.
Keep the lid on when not in use.
Swap the bucket when it is about three-quarters full. Not to the brim, because it has to be carried.
Carry it out and empty it onto the heap.
Rinse the empty bucket with a little water, tip the rinse water onto the heap, and add fresh cover material.

Empty every few days rather than letting it fill completely. A part-full bucket is far easier and safer to carry, and the smell only becomes an issue when the material is disturbed.

Wash hands afterwards, every time, without exception. This is the single most important hygiene behaviour in the entire sanitation domain, and it is the one that lapses when water is short. Keep a dedicated handwashing point next to the toilet and next to the heap.

The compost heap

Method:

Start with a thick base of coarse material: straw, hay, brash, wood chip, half a metre of it. This absorbs liquid and lets air in from below.
Always deposit into a hollow in the centre of the heap, then cover immediately and completely with straw, hay or leaves.
Never leave anything exposed.
Add kitchen scraps, garden waste and cover material to the same heap. A mixed heap composts far better than a single-input one.
Do not turn it if you are following the classic method. Building it undisturbed and letting it cure is the point.
When it is full, cap it thickly with straw and start a second heap.

A well-built heap heats to 50 to 65°C in its core within days, and that thermophilic phase does most of the pathogen destruction: 55°C sustained for 72 hours is generally sufficient for common pathogens, and 62°C kills them within about an hour.

A heap that does not heat still works, just more slowly, relying on time rather than temperature. That is precisely why the curing year exists.

The year, which is not negotiable

DANGER

Leave the finished heap for at least one year before using the compost, and two years is better.

That figure comes from the playbook and it is correct. This page does not soften it and neither should anything else.

Why it matters: roundworm and other parasite eggs are remarkably durable and can survive months. Thermophilic heat kills them if the heap gets hot enough throughout, and the centre of a home heap gets hot while the edges do not. The curing year is the safety margin that covers the material which never reached temperature.

Then, even after a year:

Use it on fruit trees, hedges, ornamentals and soil improvement.
Do not use it on root vegetables or anything eaten raw. Salad, carrots, radishes, strawberries.
Wash hands after handling it.

Do not shorten the year because the heap looks and smells like ordinary compost. It will. Finished humanure compost is dark, crumbly, earthy and entirely unremarkable, and that appearance tells you nothing about parasite eggs. This is the same principle as the canning failure page: the sensory check does not test for the thing that matters.

When it smells

A correctly run system smells of sawdust and nothing else. A smell means something specific.

Smell	Cause	Fix
Ammonia in the bucket	Not enough cover material	More cover, every use
Faecal smell in the bucket	Material exposed	Cover completely
Smell from the heap	Deposits not covered on the heap	Always cover with straw immediately
Sour, sewage smell from the heap	Too wet, gone anaerobic	Add coarse dry carbon, improve the base
Flies	Something exposed somewhere	Find it and cover it

Flies are the signal to act on immediately, not the smell. Flies mean an exposed surface, an exposed surface means faecal-oral transmission, and that is the thing this whole system exists to prevent.

In a household with children, keep the toilet area and the heap firmly out of bounds, and make handwashing a rule that is enforced rather than encouraged. The children's tier says the same thing from the other side.