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D-1 Water Distribution Exam > Sample Questions > Flashcards

Sample Questions Flashcards

1
Q

Shoring is required for trenches how deep per Osha guidelines?

A

5 feet

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2
Q

The conversion of liquid water to gaseous water is known as?

A

Evaporation

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3
Q

Who does the distribution operator ultimately answer to?

A

The water consumers

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4
Q

What does a water distribution system consist of?

A

Pipes, tanks, valves, hydrants, and other appurtenances

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5
Q

What is the leading cause of water-borne illness in the United States?

A

Backflow of non-potable water into potable water systems

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6
Q

What type of records should be kept daily in a water distribution system?

A

Chlorine residuals, flows and time cards

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7
Q

What is in a surge tank that helps prevent water hammer?

A

Air space

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8
Q

If a utility takes a monthly coliform sample and the results show that the same was positive, what should the utility do first?

A

Restest, site, upstream, downstream, and notify primacy agency with 24 hours

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9
Q

Elevated storage tanks are usually located in towns where the land is?

A

Flat

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10
Q

A centrifugal pump should never be operated unless the impeller is submerged in water or primed. What could cause a centrifugal pump to lose its prime?

A

A malfunctioning foot valve

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11
Q

What is the best preventative measure to protect a water storage tank from corrosion?

A

Painting the tank

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12
Q

When a person is working inside a water storage tank, how many people should be standing by in case of emergency?

A

Two

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13
Q

What is the most efficient way to prevent the water in a storage tank from freezing?

A

Raise and lower water levels often

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14
Q

In a water distribution system the hydraulic grade line will always slope?

A

Downward in the direction of flow

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15
Q

Name two types of displacement meters

A

Nutating disc and piston meters

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16
Q

What is the most common type of valve used to isolate sections of main lines to permit repair or replacement?

A

Gate Valve

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17
Q

All water pipes shall be installed at least 10 feet horizontally away from any and all sewer lines and how many feet above any and all sewer lines?

A

12 inches

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18
Q

When installing new water main, there must be a minimum cover of how many inches?

A

30 inches

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19
Q

Fire hydrants are usually installed at intersections and should never be more than how many feet apart?

A

500 feet

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20
Q

What is a double check valve used for?

A

Backflow

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21
Q

How can a buried plastic water pipe be located using electronic equipment?

A

Tracer wire or tape

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22
Q

The absolute minimum pressure psi delivered by a water distribution system is?

A

15 psi

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23
Q

Breakpoint chlorination is?

A

The addition of chlorine until the demand has been met

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24
Q

Where should a self-containing breathing aparatus be stored when a water utility uses chlorine gas as a disinfectant?

A

Just outside the chlorine room

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25
Q

What advantage does using monochloramines as a disinfectant have over free chlorine?

A

Less chance of THMs

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26
Q

If a chlorine cylinder were to leak one liter of liquid, how many liters of gas would be produced?

A

460 liters

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27
Q

If a water source has a large quantity of inorganic reducing agents, the chlorine dose will be probably..?

A

Be increased

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28
Q

If an operator enters a building and finds that a chlorine cylinder is leaking, what is the first thing the operator should do?

A

Exit the building

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29
Q

When disinfecting a newly laid water main, what type of disinfectant is usually used?

A

Calcium hypochlorite tablets

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30
Q

When taking a bacteriological sample, the chlorine must be neutralized in the sample. What product is used to neutralize the chlorine in a bacti sample?

A

Sodium thiosulphate

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31
Q

What happens when calcium hypochlorite comes into contact with petroleum products?

A

Fire

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32
Q

What could cause a decrease in a free chlorine residual within a distribution system?

A

Increased turbidity

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33
Q

Airborne problems that an operator may experience in a confined space are?

A

Flammable substances

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34
Q

All public and private utilities are required to notify other utilities within how many days before working in a utility right of way?

A

2 days

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35
Q

What type of chlorine is used most often to disinfect groundwater wells?

A

Hypochlorites

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36
Q

Which of gas is considered flammable?

A

Hydrogen Sulfide

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37
Q

The oxygen concentration in normal breathing air is 20.9% What percentage does the level need to drop below in a confined space before the operator will need to wear SCBA gear in order to enter the confined space?

A

19.5%

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38
Q

What happens to a nutating disc meter when the water freezes?

A

Bottom plate breaks away to prevent damage

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39
Q

Confined spaces should be checked regularly for oxygen deficiency or enrichment and what must be worn to protect the workers

A

PPE (personal protection equipment)

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40
Q

Pumps and mechanical equipment used in a distribution system have guards over moving parts because?

A

It insures operator safety from injury

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41
Q

What type of meter is used when water flow fluctuates widely?

A

Compound meters

42
Q

What is the most common type of water quality complain?

A

Tastes and odors

43
Q

What could be the cause of a pump losing its prime?

A

A defective foot valve

44
Q

What is the greatest problem for most distribution system shutoff valves?

A

Lack of operation

45
Q

What condition can cause backflow in a water distribution system?

A

Negative pressure (vacuum)

46
Q

Which problem has consistently caused more waterborne disease outbreaks in the United States than any other reported factor?

A

Contamination resulting from backflow through cross connections

47
Q

Which condition produces more leakage in a distribution system?

A

Higher pressures

48
Q

Which mandatory test must be performed on water in a storage tank before it delivers water to the distribution system?

A

Coliform organisms

49
Q

What is the major hazard when using a fixed ladder?

A

Free fall

50
Q

Disc meters are primarily used for?

A

Small flows

51
Q

If a customer within a water system has green stains on their plumbing fixtures, this home probably has?

A

Copper pipe that is reacting with aggressive water

52
Q

If new water mains were installed and disinfected with chlorine, what level of disinfection would you be required to meet?

A

Breakpoint disinfection followed by addition of more chlorine until a residual is achieved

53
Q

How often should a distribution operator change a fusible plug on a 150 lb chlorine cylinder?

A

Never

54
Q

What s a clearwell?

A

A storage vessel for treated, potable water

55
Q

If the water table that is underground drops when water is being pumped from a well, this is?

A

Drawdown

56
Q

Water meters used for small water flows only, are usually?

A

Displacement type

57
Q

Black and red stains on consumers plumbing fixtures indicated that a drinking water source may have high levels of?

A

Iron and manganese

58
Q

A check valve is usually installed to?

A

Permit the flow to only go in one direction

59
Q

A full circle clamp is used to?

A

Repair a broken or leaking water main line

60
Q

A “coupon” installed in a water distribution system which is used to determine corrosion effects on piping materials will_______________if the water has corrosive tendencies.

A

Lose weight due to corrosion

61
Q

What color should a fire hydrant be painted if it delivers less than 500 gpm according to AWWA guidelines?

A

Red

62
Q

If a trench has been dug to install a water line and the trench is deep enough to require entry and exit with ladder, this ladder must extend at least_______above the trench.

A

2.5 feet or (30 inches)

63
Q

BAT stands for?

A

Best available technology

64
Q

The lead and copper rule requires samples to be taken from the consumer’s tap after the water has sat in the lines for at least______hours?

A

6

65
Q

The water samples for the lead and copper requirements are usually taken by?

A

The distribution operator or the consumer

66
Q

When selecting a water pipe, ductile iron should not be used for a distribution system when the soil is?

A

Acidic on the pH scale

67
Q

Where should air relief valves be installed in a distribution system?

A

At the high points

68
Q

How often should a mechanical seal be greased?

A

Never

69
Q

When a water meter wears out, it will?

A

Read low or fail

70
Q

A dry tap is usually associated with?

A

Service line connections in non-pressurized pipes

71
Q

The vertical distance in feet equal to the pressure in psi at a specific joint is known as?

A

Head

72
Q

The reason most systems prefer using the “Hot Tap” wet tap method to install services on a water main is because?

A

It prevents contaminants from entering the system

73
Q

The best type of valve to use for flow control is?

A

Globe valve

74
Q

Small amounts of corrosion on the inside of pipe increases the roughness of the pipe, which reduces flow and can lead to leaks. What type of pipe is this most common in?

A

Iron pipe

75
Q

Unaccounted for water loss in a metered water system is inevitable due to leakage, hydrant water theft, failing meters and illegal connections. What percentage of water loss is generally accepted?

A

10-15%

76
Q

What toxic minerals can corrosive water cause to bleed out from certain piping material?

A

Lead and copper

77
Q

How much heavier is chlorine than air?

A

2.5 times

78
Q

Packing glands on a pump should always?

A

Be allowed to leak a few drops per minute

79
Q

When a new water line is installed parallel to a sewer line, how far apart should they be from each other?

A

10 feet

80
Q

A water system has installed a new water main line. What is the correct procedure that must be followed before bringing this water main on-line?

A

Pressure test, flush the main, disinfect the main, flush, and collect coliform samples

81
Q

Venturi meters are used primarily for?

A

Large flows

82
Q

When the cell division in bacteria has been disrupted, it?

A

Has been inactivated

83
Q

If a water purveyor receives a complain from a customer regarding black stains on their plumbing fixtures, the chances are that this water systems has a problem with

A

Manganese

84
Q

If you had some sodium thiosulphate tablets and you placed them in a clean glass bottle and used this bottle to take a coliform sample, this sample

A

Should not be used due to improper sampling procedures.

85
Q

When using screw jacks to install shoring material within a trench, the jacks should always be installed

A

From top to bottom

86
Q

If flushing and or pressurized air are unsuccessful in cleaning the inside of a water main, other options are

A

Pigs and swabs

87
Q

What classification of fire extinguisher is used for an electrical fire?

A

C type

88
Q

Intestinal parasites that may be transmitted by water are?

A

Giardia and cryptosporidium

89
Q

What is the minimum ground cover that can cover a buried water pipe?

A

30 inches

90
Q

The maximum safe withdrawal rate per day from a 150-pound cylinder of chlorine is

A

40-42 pounds per day

91
Q

Iron in groundwater supply remains in solution until it is exposed to oxygen. Once it has been exposed to oxygen it comes out of solution and creates what color in water?

A

Red

92
Q

Nationally, the per capita use is estimated to be

A

100 gal/cap/day

93
Q

All backflow devices should be inspected annually and repaired by a

A

certified backflow inspector

94
Q

What type of backflow device should be installed on a sewer plant connection?

A

Air gap

95
Q

If a chlorine cylinder has a small leak that is not repaired, this leak will

A

Get worse

96
Q

What step should be taken before a manual turbiditimeter can be used?

A

Should be zeroed to known calibration standards

97
Q

Hydrogen sulfide has a rotten egg odor, decreases sense of smell and can kill humans in high enough doses. Where might one find some of this toxic gas?

A

In a confined space

98
Q

The material safety data sheet on all chemicals should be

A

Used on site as long as chemicals are used and kept indefinitely

99
Q

If a customer calls a utility to turn off the water to their property so that a leak can be repaired, what might the operator suggest to the customer?

A

To install their own shutoff valve and that they will be responsible for the cost of the water that passed through the meter

100
Q

When operating a positive displacement pump, the discharge valve

A

Should never be closed while in operation

D-1 Water Distribution Exam (4 decks)

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