D2 Water Distribution Operator Practice Exam 2
Newest 2026 Questions and Correct Detailed
Answers Already Graded A+
What could be used to find a chlorine gas leak, which produces white smoke
when it reacts with this substance? - CORRECT ANSWER-Spray ammonia
solution vapor near leak
What causes staining of plumbing fixtures? - CORRECT ANSWER-Iron and
manganese
How long should you flush the water before you collect a bactorialogical sample?
- CORRECT ANSWER-As long as necessary to flush stagnant water from the
service pipe
What is the purpose of a surge tank? - CORRECT ANSWER-Protect pipelines
from sudden high pressure
What is recommended if a chlorine gas cylinder is leaking? - CORRECT
ANSWER-Rotate the cylinder and turn the leak upwards
,What is the purpose of primary MCL? - CORRECT ANSWER-To protect human
health
Which process converts ammonia to nitrites and nitrates? - CORRECT
ANSWER-Nitrification
What is the maximum advisable rate of chlorine gas removal from a 150-pound
cylinder? - CORRECT ANSWER-40 lbs/day
Which of the following is a type of positive displacement water meter? -
CORRECT ANSWER-nutating-disk meter
__________ is a power-operated mechanism for opening and closing a valve. -
CORRECT ANSWER-actuator
What is required if a routine sample test positive for total coliform bacteria? -
CORRECT ANSWER-Take repeat samples
why is a grid layout better than a tree (branching) layout for a water distribution
system? - CORRECT ANSWER-less dead-end mains
, What is the purpose of a reduced pressure principle assembly? - CORRECT
ANSWER-prevents back-pressure and back-siphonage
in general, at what depths is shoring required for a trench, if you're excavating in
soil? - CORRECT ANSWER-5 feet or deeper
What occurs after breakpoint chlorination is achieved? - CORRECT ANSWER-
Free available chlorine residual is directly proportional to the amount of chlorine
added
What is used to automatically shut off the flow into a tank when the water level
reaches a predetermined level? - CORRECT ANSWER-Altitude valve
What problem could be caused by water with a pH of 5.3? - CORRECT
ANSWER-Corrosion
What is a common way to connect a new pipe to an existing type, while the latter
is pressurized and in service? - CORRECT ANSWER-Wet tap or hot tap
What impact would organics have on chlorine demand? - CORRECT ANSWER-
Increase chlorine demand
Newest 2026 Questions and Correct Detailed
Answers Already Graded A+
What could be used to find a chlorine gas leak, which produces white smoke
when it reacts with this substance? - CORRECT ANSWER-Spray ammonia
solution vapor near leak
What causes staining of plumbing fixtures? - CORRECT ANSWER-Iron and
manganese
How long should you flush the water before you collect a bactorialogical sample?
- CORRECT ANSWER-As long as necessary to flush stagnant water from the
service pipe
What is the purpose of a surge tank? - CORRECT ANSWER-Protect pipelines
from sudden high pressure
What is recommended if a chlorine gas cylinder is leaking? - CORRECT
ANSWER-Rotate the cylinder and turn the leak upwards
,What is the purpose of primary MCL? - CORRECT ANSWER-To protect human
health
Which process converts ammonia to nitrites and nitrates? - CORRECT
ANSWER-Nitrification
What is the maximum advisable rate of chlorine gas removal from a 150-pound
cylinder? - CORRECT ANSWER-40 lbs/day
Which of the following is a type of positive displacement water meter? -
CORRECT ANSWER-nutating-disk meter
__________ is a power-operated mechanism for opening and closing a valve. -
CORRECT ANSWER-actuator
What is required if a routine sample test positive for total coliform bacteria? -
CORRECT ANSWER-Take repeat samples
why is a grid layout better than a tree (branching) layout for a water distribution
system? - CORRECT ANSWER-less dead-end mains
, What is the purpose of a reduced pressure principle assembly? - CORRECT
ANSWER-prevents back-pressure and back-siphonage
in general, at what depths is shoring required for a trench, if you're excavating in
soil? - CORRECT ANSWER-5 feet or deeper
What occurs after breakpoint chlorination is achieved? - CORRECT ANSWER-
Free available chlorine residual is directly proportional to the amount of chlorine
added
What is used to automatically shut off the flow into a tank when the water level
reaches a predetermined level? - CORRECT ANSWER-Altitude valve
What problem could be caused by water with a pH of 5.3? - CORRECT
ANSWER-Corrosion
What is a common way to connect a new pipe to an existing type, while the latter
is pressurized and in service? - CORRECT ANSWER-Wet tap or hot tap
What impact would organics have on chlorine demand? - CORRECT ANSWER-
Increase chlorine demand
