---
title: "Design a VIP latrine, household of 10"
subject: "Sanitary Engineering"
chapter: 9
key: "semester_6/sanitary_engineering:vip-latrine-design-10-persons"
source: https://www.bctengineer.com/q/semester_6/sanitary_engineering/vip-latrine-design-10-persons
site: BCT Engineering
---

# Design a VIP latrine, household of 10

Sanitary Engineering · Chapter 9: Disposal of Sewage from Isolated Buildings

- Asked in: 2073 Bhadra, 4 marks
- Video: [RURAL SANITATION, PART 58, ENVIRONMENTAL ENGINEERING](https://www.youtube.com/watch?v=LgLWcC54rJU) — Vidhya Focus-2020
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/sanitary_engineering/vip-latrine-design-10-persons
- Whole chapter: https://www.bctengineer.com/md/semester_6/sanitary_engineering/chapter-9

## Question

Design a VIP latrine for a household with 10 numbers of people. Assume necessary data suitably.

## Short answer

Based on 0.04 m³/person/year sludge accumulation and 2-year pit usage, each pit needs 0.8 m³. Provide two pits 1.0 m × 1.0 m × 1.5 m deep including free space, 0.5 m apart, with RCC slab, 150 mm vent pipe, and dark superstructure.

## Answer

**Assumptions:** wet pit (water used for cleaning), sludge accumulation 0.04 m³/person/year; double-pit system with each pit used for 2 years; free space above sludge 0.5 m; users = 10.

#### Pit size (each of two pits)

$$
V = n \times r \times T = 10 \times 0.04 \times 2 = 0.8\ \text{m}^3
$$

Adopt a pit 1.0 m $\times$ 1.0 m in plan: depth for sludge $= 0.8/1.0 = 0.8$ m. Add free space 0.5 m: depth $= 1.3$ m, adopt **1.5 m**.

#### Other provisions

- Two pits of 1.0 m $\times$ 1.0 m $\times$ 1.5 m, 0.5 m apart, lined with open-jointed brick/stone masonry, top 0.3 m watertight.
- RCC slab with squat hole and foot rests; hole over the second pit sealed with a lid.
- Vent pipe: 150 mm dia (min. 110 mm) PVC pipe, 0.5 m above the roof, fly screen at top.
- Superstructure 1.0 m $\times$ 1.2 m $\times$ 2.0 m, dark inside with door facing away from the sun.
- At least 15 m from water source; pit bottom at least 1.5 m above ground-water table.

```text
   vent pipe (150 mm, screen)
       |   ____________
       |  | superstruct |
  _____|__|____O________|__ slab
  | Pit 1 |    | Pit 2  |   1.0 x 1.0 x 1.5 m
  |  use  | 0.5 |  rest |
```

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Why are two pits provided?
   A. One is used while the other rests and sludge digests
   B. To double the capacity of a single user
   C. To separate urine
   D. To allow flushing
   Answer: A. The second pit is used after the first fills, while contents of the first become safe. (Key point: Double pit)

2. Volume of each pit?
   A. 0.4 m^3
   B. 0.8 m^3
   C. 1.6 m^3
   D. 4.0 m^3
   Answer: B. V = 10 x 0.04 x 2 = 0.8 m^3. (Key point: Pit volume)

3. For 1 m x 1 m plan, depth adopted?
   A. 0.8 m
   B. 1.3 m exactly with no rounding
   C. 1.5 m
   D. 2.5 m
   Answer: C. 0.8 m sludge + 0.5 m free = 1.3 m, adopted 1.5 m. (Key point: Depth)

## Related in Sanitary Engineering

- [Double pit VIP latrine for 15 users](https://www.bctengineer.com/question.md?key=semester_6%2Fsanitary_engineering%3Avip-double-pit-15-users) — Sanitary Engineering, chapter 9, asked 2×
- [VIP latrine and septic tank, family of 10](https://www.bctengineer.com/question.md?key=semester_6%2Fsanitary_engineering%3Avip-latrine-septic-tank-10-family) — Sanitary Engineering, chapter 9
- [VIP latrine; septic tank for 15 users](https://www.bctengineer.com/question.md?key=semester_6%2Fsanitary_engineering%3Avip-septic-tank-15-users-80lpcd) — Sanitary Engineering, chapter 9
- [VIP latrine: working and design procedure](https://www.bctengineer.com/question.md?key=semester_6%2Fsanitary_engineering%3Avip-latrine-working-design) — Sanitary Engineering, chapter 9, asked 2×
- [Septic tank and soak pit, household of 80](https://www.bctengineer.com/question.md?key=semester_6%2Fsanitary_engineering%3Aseptic-tank-soak-pit-80-persons) — Sanitary Engineering, chapter 9, asked 2×

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