1. Concept Explanation (Exam-Focused)
Conduits & Distribution System deal with transporting
treated water from treatment plant to consumers safely and efficiently.
In SSC JE / RRB JE, this chapter is tested through:
✔ Direct theory MCQs
✔ Network identification questions
✔ Numericals on velocity, discharge & head
loss
✔ Statement-based conceptual traps
📌 Golden Exam Rule:
Distribution system starts after water treatment is
complete.
Main Components
- Conduits
(Pipes) – Carry water
- Distribution
Reservoirs – Balance demand
- Valves
& Appurtenances – Control flow
- Distribution
Network – Delivers water to consumers
2. Types of Water Distribution Systems (VERY IMPORTANT)
1️⃣ Dead-End (Tree) System
✔ Simple & economical
❌
Stagnation at ends
📌 Used in: Old
towns
2️⃣ Grid Iron System (MOST ASKED)
✔ Rectangular pipe layout
✔ Good pressure distribution
✔ No stagnation
📌 Best system for JE
answers
3️⃣ Ring (Circular) System
✔ Ring main around city
✔ High reliability
4️⃣ Radial System
✔ Zonal distribution from
central reservoir
✔ Best pressure control
🧠 Mnemonic:
“D-G-R-R = Dead, Grid, Ring, Radial”
3. Types of Conduits (Pipes)
Common Pipe Materials
✔ Cast Iron (CI)
✔ Ductile Iron (DI)
✔ Steel
✔ PVC / HDPE
📌 Exam Favorite:
DI pipes are replacing CI pipes due to flexibility &
strength
4. Important Formulas (Highly Repeated)
1️⃣ Velocity of Flow
2️⃣ Discharge
3️⃣ Head Loss (Hazen–Williams –
Conceptual)
✔ Head loss ∝
Length
✔ Head loss ∝ Velocity²
(Numericals rarely asked; concept tested)
4️⃣ Standalone Centered Equation
(KEY REVISION)
🧠 Short Trick:
“Too slow → sediment | Too fast → pipe damage”
5. Short Notes / One-Liners (Last-Day Revision)
✔ Grid iron system gives uniform
pressure
✔ Dead-end system causes stagnation
✔ Service reservoirs balance hourly demand
✔ Valves are required for maintenance &
control
✔ Recommended pressure in distribution ≈ 7–17 m
6. PYQ Patterns (SSC JE / RRB JE)
🔹 Identification of best
distribution system
🔹
MCQs on advantages/disadvantages
🔹
Velocity-related conceptual questions
🔹
Material-based pipe questions
⚠ Typical Trap:
Radial system ≠ Ring system
7. Solved Examples
Example 1 (Numerical – Velocity)
Discharge = 0.05 m³/s
Pipe diameter = 0.25 m
✅ Answer: Velocity is within
safe limit
Example 2 (Conceptual)
Which system avoids stagnation?
✅
Answer: Grid iron system
8. MCQs (Exam Level – 30 Questions)
1. Best water distribution system for uniform pressure
is:
A) Dead-end
B) Grid iron
C) Radial
D) Ring
✅
Ans: B
2. Dead-end system is also called:
A) Ring system
B) Radial system
C) Tree system
D) Grid system
✅
Ans: C
3. Stagnation of water occurs mainly in:
A) Grid system
B) Ring system
C) Radial system
D) Dead-end system
✅
Ans: D
4. Which distribution system is most suitable for planned
cities?
A) Dead-end
B) Grid iron
C) Random
D) Branch
✅
Ans: B
5. Radial system requires:
A) No reservoir
B) Multiple reservoirs
C) Central reservoir
D) Elevated tank only
✅
Ans: C
6. Which distribution system has maximum chances of water
stagnation?
A) Grid iron
B) Ring
C) Radial
D) Dead-end
✅
Answer: D
📝
Explanation: Dead ends cause low velocity & stagnation
7. Dead-end system is most suitable for:
A) Large planned cities
B) Industrial areas
C) Old unplanned towns
D) High-rise buildings
✅
Answer: C
8. Which distribution system provides alternative paths
for water flow?
A) Dead-end
B) Grid iron
C) Tree system
D) Branch system
✅
Answer: B
9. Ring system is mainly adopted to:
A) Reduce cost
B) Increase stagnation
C) Improve reliability
D) Reduce pipe length
✅
Answer: C
10. Radial system consists of:
A) Grid layout
B) Circular pipes only
C) Zones supplied from central reservoir
D) Dead ends
✅
Answer: C
11. Which system gives the best pressure control?
A) Dead-end
B) Grid iron
C) Ring
D) Radial
✅
Answer: D
12. Recommended velocity of water in distribution pipes
is:
A) 0.1–0.3 m/s
B) 0.3–0.6 m/s
C) 0.6–2.0 m/s
D) 2.5–4.0 m/s
✅
Answer: C
13. Low velocity in distribution pipes leads to:
A) Pipe bursting
B) Cavitation
C) Sedimentation
D) Noise
✅
Answer: C
14. High velocity in pipes may cause:
A) Sedimentation
B) Water hammer
C) Algae growth
D) Stagnation
✅
Answer: B
15. Which pipe material is most commonly used now in
water supply projects?
A) Cast iron
B) Steel
C) Ductile iron
D) Concrete
✅
Answer: C
16. CI pipes are being replaced by DI pipes because DI
pipes are:
A) Cheaper
B) Brittle
C) Flexible & strong
D) Corrosion-free
✅
Answer: C
17. Service reservoirs are provided to:
A) Treat water
B) Store raw water
C) Balance demand & supply
D) Increase pressure only
✅
Answer: C
18. Which reservoir supplies water by gravity?
A) Underground reservoir
B) Ground-level reservoir
C) Elevated service reservoir
D) Sump
✅
Answer: C
19. Minimum pressure required at consumer end is
approximately:
A) 2 m
B) 5 m
C) 7 m
D) 25 m
✅
Answer: C
20. Maximum desirable pressure in distribution system is
about:
A) 5 m
B) 10 m
C) 17 m
D) 30 m
✅
Answer: C
21. Discharge through a pipe is given by:
A) Q = V/A
B) Q = A/V
C) Q = A × V
D) Q = V²/A
✅
Answer: C
22. Area of a pipe of diameter D is:
A) πD²
B) πD²/2
C) πD²/4
D) 2πD
✅
Answer: C
23. If discharge is constant and diameter is reduced,
velocity will:
A) Decrease
B) Remain same
C) Increase
D) Become zero
✅
Answer: C
24. Which of the following is NOT an appurtenance?
A) Valve
B) Hydrant
C) Manhole
D) Air valve
✅
Answer: C
25. Fire hydrants are provided mainly for:
A) Domestic supply
B) Industrial supply
C) Fire fighting
D) Pressure regulation
✅
Answer: C
26. Which valve is used to release trapped air from
pipelines?
A) Sluice valve
B) Check valve
C) Air valve
D) Scour valve
✅
Answer: C
27. Scour valves are provided at:
A) High points
B) Low points
C) Pump house
D) Reservoir inlet
✅
Answer: B
28. Which statement is TRUE?
A) Grid iron system is cheapest
B) Dead-end system gives uniform pressure
C) Ring system is more reliable than dead-end
D) Radial system has no reservoir
✅
Answer: C
29. Loss of head in pipes mainly depends on:
A) Pipe colour
B) Pipe material only
C) Velocity & length
D) Pressure only
✅
Answer: C
30. Which statement is INCORRECT?
A) DI pipes are flexible
B) Dead-end system has stagnation
C) Grid system has alternate paths
D) Radial system is cheapest
✅
Answer: D
📝
Explanation: Radial system is costlier due to reservoirs & zoning
Last-Minute JE Memory Trick 🧠
“Dead = Cheap & Stagnant | Grid = Uniform | Ring =
Reliable | Radial = Pressure Control”