Latrine Building

Part of Sanitation and Hygiene

A properly built latrine is the most important structure in any settlement — more important than shelters, storage, or walls. This guide covers site selection, the two main latrine types (pit and composting), step-by-step construction of a basic pit latrine, and the ventilated improved pit (VIP) design that eliminates flies and odor.

Site Selection

Choosing the wrong location for a latrine can contaminate your water supply and sicken the entire settlement. Every other decision depends on getting this right.

The Non-Negotiable Rules

1. Minimum 30 meters from any water source — wells, springs, streams, ponds. In sandy or gravelly soil, increase to 50 meters. In fractured rock, 100 meters.
2. Downhill from your water source — groundwater follows surface slope. A latrine uphill from your well sends contamination straight into your drinking water.
3. Above the water table — the bottom of the pit must be at least 1.5 meters above the highest seasonal groundwater level. Dig a test hole 2 meters deep and wait 24 hours. If water seeps in, the site is unsuitable for a pit latrine.
4. Downwind from living areas — prevailing wind carries odor. Observe wind patterns for a full day before choosing the site.
5. At least 6 meters from any building — for odor control and to prevent undermining foundations.
6. Accessible path — if people will not use it at night or in rain, they will defecate elsewhere. A clear, short, lit path from sleeping areas is essential.

The Water Table Test

Dig a test hole to your planned pit depth. Wait 24 hours. If water appears at ANY point, that location cannot support a pit latrine. Consider a composting toilet instead (see Composting Toilet) or choose a different site with higher ground.

Soil Assessment

Soil Type	Suitability	Notes
Firm clay	Good	Holds shape well, may need less lining. Slow drainage — good for containment.
Loam (mixed)	Excellent	Ideal balance of stability and drainage
Sandy soil	Fair	Collapses easily — requires full pit lining. Drains fast — increase distance from water.
Gravel	Poor	Unstable, no filtration. Avoid if possible.
Rock	Unsuitable	Cannot dig deep enough. Use composting toilet.
Waterlogged	Unsuitable	Water table too high. Use raised composting toilet.

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Pit Latrine vs. Composting Toilet

Before you start digging, decide which system suits your conditions.

Feature	Pit Latrine	Composting Toilet
Best for	Stable soil, low water table	High water table, rocky soil, compost production
Depth required	2-3 meters	Surface level (raised chamber)
Construction effort	1-2 days, 2 people	2-4 days, more materials
Lifespan per unit	2-3 years (family of 5-6)	Ongoing with container rotation
Maintenance	Add ash/soil daily, check pit level monthly	Add carbon daily, rotate containers, manage compost
Produces compost	Yes, after 2+ years of decomposition	Yes, after 6-12 months
Fly/odor risk	Moderate (mitigated by lid + VIP design)	Low (carbon layering suppresses both)

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Basic Pit Latrine: Step-by-Step Construction

Materials Needed

• Digging tools (shovel, pick, sharpened stakes)
• Logs or poles, 10-15 cm diameter, at least 2 meters long (for slab/platform)
• Smaller poles or branches (for superstructure frame)
• Covering material: thatch, bark panels, woven branches, fabric, or any opaque sheeting
• Stones or additional logs (for pit lining if soil is loose)
• Flat stone or wooden disc (for squat hole cover)
• Bucket + scoop for covering material (ash, dry soil, lime)

Step 1: Dig the Pit

Dimensions: 1 meter wide x 1.5 meters long x 2.5 meters deep (minimum 2 meters, 3 meters preferred for longer life).

• Keep sides as vertical as possible
• Pile excavated soil nearby — you will use it for covering waste and eventually filling the pit
• If soil starts collapsing during digging, you need to line the pit (see Step 2)

Pit Life Calculation

A pit 1m x 1.5m x 2.5m = 3.75 cubic meters usable volume. A family of 5 produces approximately 1.5 cubic meters of waste per year (including covering material). This gives roughly 2-2.5 years of use before the pit must be closed.

Step 2: Line the Upper Pit

Line at least the top 60 cm of the pit walls to prevent collapse at the surface where the slab sits. Methods:

• Stacked stones — dry-stacked with no mortar, allowing some drainage
• Logs or split poles — placed vertically against the pit wall, held by horizontal cross-braces
• Woven branches — a basket-weave cylinder pressed against the pit walls

In sandy or unstable soil, line the entire pit depth to prevent wall collapse.

Step 3: Build the Slab (Platform)

The slab spans the pit and supports the user. It must be strong enough to hold an adult safely.

Log slab method:

1. Lay strong poles (10-15 cm diameter) across the short dimension (1 meter span) of the pit, spaced 5 cm apart
2. Pack the gaps with smaller sticks, bark, or packed clay
3. Leave a hole 20-25 cm in diameter near the center — this is the squat opening
4. Cover the entire slab with 5-10 cm of packed clay or mud for a smooth, cleanable surface
5. Allow to dry completely before use

Raised lip: Build a small rim (5-10 cm high) around the squat hole to prevent surface water from running into the pit.

Structural Safety

Test the slab by placing the heaviest person in your group on it before declaring it ready. A slab failure drops someone into a pit of waste — this is a genuine medical emergency (infection risk from immersion in sewage, plus possible injury from the fall).

Step 4: Build the Superstructure (Enclosure)

Privacy is not optional — people who feel exposed will not use the latrine, and the entire sanitation system fails.

Minimum enclosure:

• Three walls + door/curtain — the open side or door faces away from the settlement’s common areas
• Height: at least 1.8 meters for standing privacy
• Roof: strongly recommended — rain turns the slab slippery and dilutes covering material
• Ventilation: leave a 15-20 cm gap between the top of the walls and the roof for airflow

Construction methods:

• Pole frame with woven branch panels (wattle)
• Pole frame with fabric, bark, or thatch panels
• Stacked stone walls (more permanent)
• Any combination that provides privacy, weather protection, and ventilation

Step 5: Install the Squat Hole Cover

Cut a flat stone or wooden disc that fits snugly over the squat hole. This cover must be:

• Easy to remove and replace with one hand
• Heavy enough not to blow off in wind
• Present at all times — if it goes missing, flies colonize the pit within hours

Step 6: Set Up Covering Material

Place a bucket of covering material and a scoop inside the latrine. After every use, the user scoops a generous amount over the waste.

Covering material options (best to least effective):

1. Wood ash (alkaline, kills bacteria, absorbs moisture)
2. Quicklime or slaked lime (strong disinfectant, excellent odor control)
3. Dry soil or sand (basic coverage, moderate odor control)
4. Dry leaves or sawdust (good carbon source, moderate odor control)

Refill the bucket daily. If the bucket is empty, people skip the covering step, and fly/odor problems begin immediately.

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Ventilated Improved Pit (VIP) Latrine

The VIP design is a major upgrade over the basic pit latrine. It virtually eliminates flies and reduces odor to near zero, using only a vent pipe and darkness.

How It Works

The VIP latrine exploits fly behavior and convection:

1. The interior of the latrine is kept dark (no gaps in walls or roof that admit sunlight)
2. A vent pipe (10-15 cm diameter) extends from inside the pit, up through the roof, to at least 50 cm above the roofline
3. A fly screen (fine mesh, fabric, or tightly woven plant fiber) covers the top of the vent pipe
4. Wind blowing across the top of the pipe creates a draft that pulls air up through the pit and out the vent — carrying odor out and away
5. Flies inside the pit are attracted to the light at the top of the vent pipe. They fly up, hit the screen, and cannot escape. They die on the screen.
6. Flies outside cannot enter through the screen
7. The dark interior means flies do not enter through the squat hole (flies avoid darkness)

VIP Construction Additions

Everything is the same as a basic pit latrine, plus:

1. Vent pipe: A hollow tube — bamboo, PVC pipe, hollowed log, or a cylinder made from bark or sheet metal — at least 10 cm internal diameter
2. Pipe placement: Insert through the slab on the downwind side of the pit, angled up through the wall and roof, extending at least 50 cm above the roof peak
3. Fly screen: Attach fine mesh over the top opening. Must be fine enough to stop flies (<2 mm gaps). Replace when damaged.
4. Dark interior: Seal all wall gaps and ensure the doorway faces away from the sun or has a light-blocking curtain. The ONLY light source should be the vent pipe top.
5. No squat hole cover needed: The darkness keeps flies out. However, a cover is still recommended during heavy rain.

Paint or Darken the Vent Pipe

If using a light-colored pipe, darken the exterior by rubbing with charcoal or wrapping with dark material. A dark pipe absorbs solar heat, warming the air inside and increasing the updraft — improving both odor removal and fly trapping.

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Handwashing Station Integration

A latrine without a handwashing station is half a sanitation system. Place the station immediately outside the latrine door so that using it is unavoidable.

Simple Tippy-Tap Design

1. Fill a jug, gourd, or container with clean water. Hang from a frame at hand height.
2. Tie a cord from the container to a foot lever (a stick on the ground). Stepping on the lever tips the container, pouring water — no hand contact needed.
3. Place wood ash, sand, or soap on a small shelf beside the station.
4. Hang a clean drying cloth.
5. Refill water daily. Replace ash/soap as needed.

No Handwashing Station = Incomplete Latrine

Studies consistently show that latrines alone reduce diarrheal disease by 30-40%. Adding handwashing with soap or ash increases the reduction to 70-80%. The handwashing station is not an accessory — it is half the system.

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Maintenance Schedule

Task	Frequency	Notes
Refill covering material bucket	Daily	Empty bucket = no covering = fly problem within 24 hours
Refill handwashing station water	Daily	No water = no handwashing
Check pit level	Monthly	Close pit when waste reaches 50 cm below slab
Inspect slab for cracks	Monthly	Cracks let flies in and weaken structure
Replace VIP fly screen	As needed	Damaged screen = flies escape. Check weekly.
Clean slab surface	Weekly	Scrub with ash and water. A dirty slab discourages use.
Clear vent pipe blockages	Monthly	Leaves, spider webs, or debris reduce airflow

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Key Takeaways

Latrine Building Essentials

1. Site selection is everything — 30m from water, downhill, downwind, above water table
2. Pit dimensions: 1m x 1.5m x 2.5m deep for a family of 5-6, lasting 2-3 years
3. Line the pit at least 60 cm deep at the top; full depth in unstable soil
4. Test the slab with your heaviest person before anyone uses it
5. Privacy drives usage — an exposed latrine is an unused latrine
6. VIP design eliminates flies and odor with a vent pipe + dark interior — a major upgrade for minimal extra effort
7. Handwashing station at the door — this is half the disease prevention, not optional
8. Daily maintenance is just two tasks: refill the covering material bucket and refill the handwashing water