Class C Water Exam Questions and
Complete Solutions Graded A+
THM are caused by - Answer: Reaction of chlorinated water with humic materials found in surface water
sources
THMs in finished water can cause - Answer: Cancer
What is the MCL for Trihalomethanes - Answer: 0.1 mg/L
Nitrate in levels above ______ mg/L can cause blue baby disease - Answer: 10
Water main definition - Answer: Any line that passes one property to reach another parcel of property
Name three water borne diseases - Answer: Typhoid, infectious hepatitis, and cholera
How much pressure in one foot of elevation offer? - Answer: .433 psi
Velocity of flow in a water main is expressed in _________ - Answer: Feet per second
What is the industry standard for acceptable water loss in a public water supply? - Answer: 14% or less
The average flow from a 5/8" x 3/4" water meter is _________ gpm - Answer: 18-20 gpm
How many pounds of water in a cubic foot of water? - Answer: 62.4 pounds
What is the IDPH required level of fluoride - Answer: .6 mg/L - .8 mg/L
What type of test is most commonly used for testing fluoride levels? - Answer: SPADNS
,What type of test is most commonly used for testing chlorine residuals in a small system or in a
distribution system? - Answer: DPD
What is added to a bacti sample bottle to remove the chlorine residual? - Answer: Sodium thiosulfate
Bacti sample bottles should be ___________ - Answer: Filled one inch from the top of the bottle
Bacti samples must be analyzed no later than ________ hours after collection - Answer: 30
What is the minimum "combined" chlorine residual that is required to be in all parts of a distribution
system? - Answer: 1.0 mg/L
What is the minimum "free" chlorine residual that is required to be in all parts of a distribution system? -
Answer: 0.5 mg/L
What does chlorine breakdown into? - Answer: hypochlorite ion and hypochlorous acid
What is total chlorine? - Answer: The amount of chlorine remaining after a given contact period
What is the percentage of available chlorine in gas chlorine? - Answer: 100%
What is the percentage of available chlorine in calcium hypochlorite? - Answer: 65-70%
What is the percentage of available chlorine in sodium hypochlorite? - Answer: 10-15%
If calcium hypochlorite and oily rags are allowed to come into contact with each other what will occur? -
Answer: Ignition and flash fire will occur
, What is the purpose of poly-pigging a water main? - Answer: Progressive poly pigging is a process that
involves propelling a "pig" constructed of foam of varied densities through a pipeline. As it travels
through the pipe it loosens, removes and transports debris to an access point like a manhole where it
can be removed by a vacuum or pump truck and transported away for disposal.
What is specific gravity as related to groundwater? - Answer: Weight of a particle, substance, or
chemical solution in relation to the weight of an equal volume of water
What is static water level? - Answer: The elevation or level of water table when the well pump is not
operating
Which component of the well supports the weight of the pumping unit? - Answer: Pump pedestal
Which component of the well permits measurement of water level by means of air pressure
measurements? - Answer: Air line water level measuring device
Which component of the well permits operator to see level of gravel and add gravel as necessary? -
Answer: Gravel tube
Which component of the well is used to remove first water pumped at start-up? - Answer: Pump blowoff
Which component of the well allows air to enter well during drawdown to prevent vacuum conditions;
vents excess air during well recovery? - Answer: Well casing vent
Which component of the well permits insertion of water lever measuring device; also used to add
cleaning agents? - Answer: Sounding tube
Which component of the well permits discharge of air in column pipe during start-up and admits air
during shutdown? - Answer: Air-release vacuum breaker valve
Which component of the well provides water tight seal between the motor base and the concrete
support pedestal? - Answer: Pump motor base seal
Complete Solutions Graded A+
THM are caused by - Answer: Reaction of chlorinated water with humic materials found in surface water
sources
THMs in finished water can cause - Answer: Cancer
What is the MCL for Trihalomethanes - Answer: 0.1 mg/L
Nitrate in levels above ______ mg/L can cause blue baby disease - Answer: 10
Water main definition - Answer: Any line that passes one property to reach another parcel of property
Name three water borne diseases - Answer: Typhoid, infectious hepatitis, and cholera
How much pressure in one foot of elevation offer? - Answer: .433 psi
Velocity of flow in a water main is expressed in _________ - Answer: Feet per second
What is the industry standard for acceptable water loss in a public water supply? - Answer: 14% or less
The average flow from a 5/8" x 3/4" water meter is _________ gpm - Answer: 18-20 gpm
How many pounds of water in a cubic foot of water? - Answer: 62.4 pounds
What is the IDPH required level of fluoride - Answer: .6 mg/L - .8 mg/L
What type of test is most commonly used for testing fluoride levels? - Answer: SPADNS
,What type of test is most commonly used for testing chlorine residuals in a small system or in a
distribution system? - Answer: DPD
What is added to a bacti sample bottle to remove the chlorine residual? - Answer: Sodium thiosulfate
Bacti sample bottles should be ___________ - Answer: Filled one inch from the top of the bottle
Bacti samples must be analyzed no later than ________ hours after collection - Answer: 30
What is the minimum "combined" chlorine residual that is required to be in all parts of a distribution
system? - Answer: 1.0 mg/L
What is the minimum "free" chlorine residual that is required to be in all parts of a distribution system? -
Answer: 0.5 mg/L
What does chlorine breakdown into? - Answer: hypochlorite ion and hypochlorous acid
What is total chlorine? - Answer: The amount of chlorine remaining after a given contact period
What is the percentage of available chlorine in gas chlorine? - Answer: 100%
What is the percentage of available chlorine in calcium hypochlorite? - Answer: 65-70%
What is the percentage of available chlorine in sodium hypochlorite? - Answer: 10-15%
If calcium hypochlorite and oily rags are allowed to come into contact with each other what will occur? -
Answer: Ignition and flash fire will occur
, What is the purpose of poly-pigging a water main? - Answer: Progressive poly pigging is a process that
involves propelling a "pig" constructed of foam of varied densities through a pipeline. As it travels
through the pipe it loosens, removes and transports debris to an access point like a manhole where it
can be removed by a vacuum or pump truck and transported away for disposal.
What is specific gravity as related to groundwater? - Answer: Weight of a particle, substance, or
chemical solution in relation to the weight of an equal volume of water
What is static water level? - Answer: The elevation or level of water table when the well pump is not
operating
Which component of the well supports the weight of the pumping unit? - Answer: Pump pedestal
Which component of the well permits measurement of water level by means of air pressure
measurements? - Answer: Air line water level measuring device
Which component of the well permits operator to see level of gravel and add gravel as necessary? -
Answer: Gravel tube
Which component of the well is used to remove first water pumped at start-up? - Answer: Pump blowoff
Which component of the well allows air to enter well during drawdown to prevent vacuum conditions;
vents excess air during well recovery? - Answer: Well casing vent
Which component of the well permits insertion of water lever measuring device; also used to add
cleaning agents? - Answer: Sounding tube
Which component of the well permits discharge of air in column pipe during start-up and admits air
during shutdown? - Answer: Air-release vacuum breaker valve
Which component of the well provides water tight seal between the motor base and the concrete
support pedestal? - Answer: Pump motor base seal
