Drinking Water Operator - Class C - Certification Review
- Fall 2025 EXAM ACTUAL COMPLETE REAL EXAM
QUESTIONS WITH COMPLETE VERIFIED SOLUTION GUIDE
(A+ GRADED 100% ACCURATE) NEWEST VERSION!! BEST
EXAM PREPARATION FOR 2026-2027
Chemical / treatment used to oxidize iron and / or manganese is drinking
water?
ANSWERS: Oxygen (through Aeration)
What water source contains more dissolved gases and minerals?
ANSWERS: Ground Water
What water source contains more pathogenic organisms?
ANSWERS: Surface Water
, What are the 3 parts of "Multiple Barrier Approach Zone" protections?
ANSWERS:
- Source Water Protection
++ 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 ( It does not matter which step you start with
)
ANSWERS: Surface water infiltration into ground
--->
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 used to reduce
runoff pollution?
ANSWERS: Gentle sloping of ground towards surface body of water
- Planting native trees, shrubs, plants, grass
- Install filter fabric underneath crushed stone and Riprap stones on
steeper slopes towards surface bodies of water
- ANSWERS: 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 removal in regard to
water filtration?
ANSWERS: Underground drain tiles move water away from area too quickly
for natural filtration process to be effective
What are the Maximum Contaminant Level ( MCL ) & Secondary Maximum
Contaminant Level ( SMCL ) [in Illinois] limits on Iron ( Fe ) and Manganese (
Mn )?
ANSWERS:
- MCL
++ Iron : 1.0 mg/L
++ 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 water?
ANSWERS:
Removal of dissolved minerals (Iron,
Manganese, etc) &
Removal of undesirable gases (Methane, Hydrogen Sulfide, Carbon
Dioxide, Ammonia, etc)
What are the primary purposes of treating surface source water?
ANSWERS: Remove or inactivate pathogenic microorganisms
Water supply treatment compliance is measured primarily by which 2
things?
ANSWERS: Turbidity & Microbial inactivation by disinfection
What is the minimum pressure level that should be kept in a distribution
system at all times?
ANSWERS: 20 psi
What is the typically ideal range of PSI pressure that should be kept in a
distribution system?
ANSWERS: 35 - 70 psi
What is the maximum pressure level for the service side of a water meter?
ANSWERS: 80 psi
- Fall 2025 EXAM ACTUAL COMPLETE REAL EXAM
QUESTIONS WITH COMPLETE VERIFIED SOLUTION GUIDE
(A+ GRADED 100% ACCURATE) NEWEST VERSION!! BEST
EXAM PREPARATION FOR 2026-2027
Chemical / treatment used to oxidize iron and / or manganese is drinking
water?
ANSWERS: Oxygen (through Aeration)
What water source contains more dissolved gases and minerals?
ANSWERS: Ground Water
What water source contains more pathogenic organisms?
ANSWERS: Surface Water
, What are the 3 parts of "Multiple Barrier Approach Zone" protections?
ANSWERS:
- Source Water Protection
++ 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 ( It does not matter which step you start with
)
ANSWERS: Surface water infiltration into ground
--->
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 used to reduce
runoff pollution?
ANSWERS: Gentle sloping of ground towards surface body of water
- Planting native trees, shrubs, plants, grass
- Install filter fabric underneath crushed stone and Riprap stones on
steeper slopes towards surface bodies of water
- ANSWERS: 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 removal in regard to
water filtration?
ANSWERS: Underground drain tiles move water away from area too quickly
for natural filtration process to be effective
What are the Maximum Contaminant Level ( MCL ) & Secondary Maximum
Contaminant Level ( SMCL ) [in Illinois] limits on Iron ( Fe ) and Manganese (
Mn )?
ANSWERS:
- MCL
++ Iron : 1.0 mg/L
++ 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 water?
ANSWERS:
Removal of dissolved minerals (Iron,
Manganese, etc) &
Removal of undesirable gases (Methane, Hydrogen Sulfide, Carbon
Dioxide, Ammonia, etc)
What are the primary purposes of treating surface source water?
ANSWERS: Remove or inactivate pathogenic microorganisms
Water supply treatment compliance is measured primarily by which 2
things?
ANSWERS: Turbidity & Microbial inactivation by disinfection
What is the minimum pressure level that should be kept in a distribution
system at all times?
ANSWERS: 20 psi
What is the typically ideal range of PSI pressure that should be kept in a
distribution system?
ANSWERS: 35 - 70 psi
What is the maximum pressure level for the service side of a water meter?
ANSWERS: 80 psi
