Drinking Water Operator - Class C
Certification Review - Fall
(2026-2027)
Final Exam Questions with Verified Answers |
Grade A+ | New Version
,Chemical / treatment used to oxidize iron and / or Oxygen (through Aeration)
manganese is drinking water?
What water source contains more dissolved gases and Ground Water
minerals?
What water source contains more pathogenic organisms? Surface Water
What are the 3 parts of "Multiple Barrier Approach Zone" - Source Water Protection
protections? ++ What can be built near water sources
- Treatment Plant & Disinfection
++ Backflow preventers
++ Disinfectant Levels
- Distribution System Integrity
++ Proactive pipe maintenance
++ Regular (Annual) valve exercising
List the steps in the Hydrologic (Water) Cycle Surface water infiltration into ground
--->
( It does not matter which step you start with ) Ground water used by plant uptake
--->
Moisture evaporates from surface
--->
Water vapor transpiration into atmosphere
--->
Clouds form in atmosphere
--->
Precipitation falls to the ground at higher points in elevation
--->
Runoff moves from higher elevation to lower elevation collecting in surface bodies
of water
What are some "Riparian Zone" restorations that can be - Gentle sloping of ground towards surface body of water
used to reduce runoff pollution?
- Planting native trees, shrubs, plants, grass
- Install filter fabric underneath crushed stone and Riprap stones on steeper slopes
towards surface bodies of water
- Install large anchor rocks (sometimes in a slight trench) on the shores or surface
body of water to limit erosion
What is a negative effect of modern farm field water Underground drain tiles move water away from area too quickly for natural filtration
removal in regard to water filtration? process to be effective
What are the Maximum Contaminant Level ( MCL ) & - MCL
Secondary Maximum Contaminant Level ( SMCL ) [in ++ Iron : 1.0 mg/L
Illinois] limits on Iron ( Fe ) and Manganese ( Mn )? ++ Manganese : 0.15 mg/L
- SMCL (in Illinois)
++ Iron : 0.3 mg/L
++ Manganese : 0.05 mg/L
What are the primary purposes of treating ground source Removal of dissolved minerals (Iron, Manganese, etc)
water?
&
Removal of undesirable gases (Methane, Hydrogen Sulfide, Carbon Dioxide,
Ammonia, etc)
, What are the primary purposes of treating surface source Remove or inactivate pathogenic microorganisms
water?
Water supply treatment compliance is measured primarily Turbidity & Microbial inactivation by disinfection
by which 2 things?
What is the minimum pressure level that should be kept in 20 psi
a distribution system at all times?
What is the typically ideal range of PSI pressure that 35 - 70 psi
should be kept in a distribution system?
What is the maximum pressure level for the service side of 80 psi
a water meter?
Measurement used for Velocity Feet Per Second ( ft/sec )
How is Flow calculated ( What is the equation ) ? "Q = V * A"
(Flow = Velocity x Area)
What is the recommended maximum velocity in a 5 ft/sec
distribution system, except for fire fighting purposes?
What 2 things determine the amount of water that can be Velocity & Pipe Diameter
transferred through a section of a distribution system?
Why is it not a good practice to "oversize" a water main? - Causes more air to be in pipes
- Causes less turnover in the system
- May degrade quality of water
What size water mains should not have fire hydrants Smaller than 6 inches
installed on them?
( Cannot supply enough pressure for adequate fire fighting flow )
Pipes must have what to be considered good for a Sufficient strength to withstand high pressures internally and externally
distribution system?
What materials have been used for pipes in water - Wood
distribution systems?
- Asbestos-Cement
( Discontinued and current materials )
- Cast Iron (C.I.P.)
- Ductile Iron (D.I.P.)
- PVC
Certification Review - Fall
(2026-2027)
Final Exam Questions with Verified Answers |
Grade A+ | New Version
,Chemical / treatment used to oxidize iron and / or Oxygen (through Aeration)
manganese is drinking water?
What water source contains more dissolved gases and Ground Water
minerals?
What water source contains more pathogenic organisms? Surface Water
What are the 3 parts of "Multiple Barrier Approach Zone" - Source Water Protection
protections? ++ What can be built near water sources
- Treatment Plant & Disinfection
++ Backflow preventers
++ Disinfectant Levels
- Distribution System Integrity
++ Proactive pipe maintenance
++ Regular (Annual) valve exercising
List the steps in the Hydrologic (Water) Cycle Surface water infiltration into ground
--->
( It does not matter which step you start with ) Ground water used by plant uptake
--->
Moisture evaporates from surface
--->
Water vapor transpiration into atmosphere
--->
Clouds form in atmosphere
--->
Precipitation falls to the ground at higher points in elevation
--->
Runoff moves from higher elevation to lower elevation collecting in surface bodies
of water
What are some "Riparian Zone" restorations that can be - Gentle sloping of ground towards surface body of water
used to reduce runoff pollution?
- Planting native trees, shrubs, plants, grass
- Install filter fabric underneath crushed stone and Riprap stones on steeper slopes
towards surface bodies of water
- Install large anchor rocks (sometimes in a slight trench) on the shores or surface
body of water to limit erosion
What is a negative effect of modern farm field water Underground drain tiles move water away from area too quickly for natural filtration
removal in regard to water filtration? process to be effective
What are the Maximum Contaminant Level ( MCL ) & - MCL
Secondary Maximum Contaminant Level ( SMCL ) [in ++ Iron : 1.0 mg/L
Illinois] limits on Iron ( Fe ) and Manganese ( Mn )? ++ Manganese : 0.15 mg/L
- SMCL (in Illinois)
++ Iron : 0.3 mg/L
++ Manganese : 0.05 mg/L
What are the primary purposes of treating ground source Removal of dissolved minerals (Iron, Manganese, etc)
water?
&
Removal of undesirable gases (Methane, Hydrogen Sulfide, Carbon Dioxide,
Ammonia, etc)
, What are the primary purposes of treating surface source Remove or inactivate pathogenic microorganisms
water?
Water supply treatment compliance is measured primarily Turbidity & Microbial inactivation by disinfection
by which 2 things?
What is the minimum pressure level that should be kept in 20 psi
a distribution system at all times?
What is the typically ideal range of PSI pressure that 35 - 70 psi
should be kept in a distribution system?
What is the maximum pressure level for the service side of 80 psi
a water meter?
Measurement used for Velocity Feet Per Second ( ft/sec )
How is Flow calculated ( What is the equation ) ? "Q = V * A"
(Flow = Velocity x Area)
What is the recommended maximum velocity in a 5 ft/sec
distribution system, except for fire fighting purposes?
What 2 things determine the amount of water that can be Velocity & Pipe Diameter
transferred through a section of a distribution system?
Why is it not a good practice to "oversize" a water main? - Causes more air to be in pipes
- Causes less turnover in the system
- May degrade quality of water
What size water mains should not have fire hydrants Smaller than 6 inches
installed on them?
( Cannot supply enough pressure for adequate fire fighting flow )
Pipes must have what to be considered good for a Sufficient strength to withstand high pressures internally and externally
distribution system?
What materials have been used for pipes in water - Wood
distribution systems?
- Asbestos-Cement
( Discontinued and current materials )
- Cast Iron (C.I.P.)
- Ductile Iron (D.I.P.)
- PVC
