250+ TOP MCQs on Systems of Plumbing and Answers

Waste Water Engineering Multiple Choice Questions on “Systems of Plumbing”.

1. How many types of pumps are present?
a) 1
b) 2
c) 3
d) 4
Answer: b
Clarification: Pumps are of two types. Submersible pumps and open type pumps. Submersible pumps require very less maintenance and are used inside water. Both types can be used for traditional as well as hydro-pneumatic system.

2. Submersible pumps require high maintenance.
a) True
b) False
Answer: b
Clarification: Submersible pumps require very less maintenance and are used inside water. Both types can be used for traditional as well as hydro-pneumatic system.

3. What is the minimum diameter of pipes used for drainage of waste water?
a) 50 mm
b) 75 mm
c) 100 mm
d) 105 mm
Answer: b
Clarification: Waste water is from showers, basins, kitchen sinks, washing machines and the like. This is also called grey water. Normally a minimum of 75 mm diameter pipes is used for drainage of waste water.

4. What is the wastewater from kitchen sinks called?
a) Grey water
b) Black water
c) Yellow water
d) Brown water
Answer: a
Clarification: Normally a minimum of 75 mm diameter pipes are used for drainage of waste water. Waste water is from showers, basins, kitchen sinks, washing machines and the like. This is also called grey water.

5. What is the water from urinals called?
a) Black water
b) Yellow water
c) Grey water
d) Brown water
Answer: a
Clarification: Soil water or sewage is from WCs and urinals. This is also called black water. Minimum of 100 mm diameter pipes are used for waste water. These can be of cast iron or of PVC.

6. What is the minimum diameter of the pipe used to collect black water?
a) 50 mm
b) 75 mm
c) 100 mm
d) 125 mm
Answer: c
Clarification: Soil water or sewage is from WCs and urinals. This is also called black water. Minimum of 100 mm diameter pipes are used for waste water.

7. What is the recommended slope ratio for soil water pipes?
a) 1:12
b) 1:20
c) 1:30
d) 1:40
Answer: d
Clarification: Soil water pipes should run at a steeper slope, such as 1:40, as they have solids. These can be of cast iron or of PVC. Minimum of 100 mm diameter pipes are used for waste water.

8. Grease should not be allowed to enter the normal drainage system.
a) True
b) False
Answer: a
Clarification: A grease trap should be used when draining waste from kitchens, grease should not be allowed to enter the normal drainage system. A grease trap is nothing but a small inspection chamber.

9. _______ is used to clean blockage in the line.
a) Lateral chamber
b) Main chamber
c) Inspection chamber
d) Sewer chamber
Answer: c
Clarification: Tone ware (ceramic) pipes are used when soil and waste water is to be transported in external soil. An inspection chamber is used to clean blockage in the line and change direction of pipes.

10. What is the shape of the septic tank?
a) Square
b) Rectangle
c) Circular
d) Oval
Answer: b
Clarification: A septic tank is a rectangular underground tank with compartments. It is always full of sewage that can be removed manually. The less water put into a septic tank, the better it will function.

11. What is the percentage of purification of septic tank effluent?
a) 30%
b) 50%
c) 70%
d) 90%
Answer: c
Clarification: The effluent that flows out of this, which is about 70% purified, is then put into a soak pit. A soak pit is a cylindrical tank with porous brick walls surrounded by a layer of gravel.

12. ________ should not be placed near water body.
a) Power generator
b) Soak pit
c) Pump stations
d) Houses
Answer: b
Clarification: A soak pit should not be placed near any occupied structure, water body or water supply pipe. The groundwater will enter and flood the pit through the porous walls. Hence, soak pit cannot be used where the water table is high.