Water Treatment Plant Operator ACTUAL TEST WITH
200 QUESTIONS AND CORRECT ANSWERS/ WATER
TREATMENT OPERATOR IN TRAINING PRACTICE TEST
LATEST 2025/2026 (NEWEST!)
What is used as a chemical coagulant? - CORRECT ANSWER-Alum
The correct order of treatment in a surface water plant is... - CORRECT ANSWER-Coagulation,
Flocculation, Sedimentation and Filtration
When should polyphosphates used for sequestration of iron and manganese from a well be injected
into the process? - CORRECT ANSWER-Right after the water leaves the well
Recarbonation is: - CORRECT ANSWER-Adding CO2 to the water
In the ion-exchange softening process, once the resin can no longer soften water it must be: -
CORRECT ANSWER-Regenerated
What should be used by an operator to test for residual chlorine? - CORRECT ANSWER-DPD (N, N-
diethyl-p-phenylenediamine)
What is a major part of a turbidimeter? - CORRECT ANSWER-Light source
pH is a measure of: - CORRECT ANSWER-Hydrogen ion concentration
What is used to indicate the clarity of water? - CORRECT ANSWER-Turbidity
After chlorination, the free chlorine residual includes: - CORRECT ANSWER-OCI- and HOC1
Under no circumstances should a composite sample be collected for which type of analysis? -
CORRECT ANSWER-Bacteriological
The number of monthly distribution system chlorine residual samples required is: - CORRECT
ANSWER-Based on population
,When one substance is dissolved in another and will not settle out, what is it called? - CORRECT
ANSWER-A solution
What is a compound that is not derived from hydrocarbons? - CORRECT ANSWER-Inorganic
compound
After initial full-service operation, grease-lubricated bearings should be regreased at what
frequency? - CORRECT ANSWER-3 to 6 months
Check valves are used to prevent? - CORRECT ANSWER-Water from flowing in two directions
If a pump is run on a regular basis, packing should be inspected: - CORRECT ANSWER-Annually
What is a function of couplings? - CORRECT ANSWER-Compensate for alignment changes
What is the correct formula for determining watts> - CORRECT ANSWER-Watts= (amps)(volts)
The main purpose of a mechanical seal is to: - CORRECT ANSWER-Keep lubrication in and dirt and
other foreign materials out
The purpose of packing is to: - CORRECT ANSWER-Control water leakage along the pump's shaft
What part of a pump houses the packing or mechanical seal? - CORRECT ANSWER-The stuffing box
What type of pump can be operated against a closed valve? - CORRECT ANSWER-Centrifugal pump
What is a principal problem associated with preliminary treatment screening? - CORRECT ANSWER-
Clogging
Opening the discharge valve one full turn on a chlorine cylinder will: - CORRECT ANSWER-Permit
maximum discharge
, Tubercles can form on which type of pipe? - CORRECT ANSWER-Ductile iron
What is a primary indicator of bearing failure? - CORRECT ANSWER-Noise from pump
What disease is capable of being transmitted by water? - CORRECT ANSWER-Typhoid
When any piece of electrical equipment is being worked on, the circuit breaker should be: -
CORRECT ANSWER-De-energized and locked out
Which of the following directly impacts the treatment of drinking water?
A. Fair Labor Standards Act
B. Food Security Act
C. Safe Drinking Water Act
D. Clean Air Act - CORRECT ANSWER-C. Safe Drinking Water Act
Corrosive water acting on a customer's plumbing may cause what metal to enter their drinking
water? - CORRECT ANSWER-Lead
What is the most important thing to consider in automatic startup after a power failure? - CORRECT
ANSWER-Operator Safety
On a 30 minute SCBA air pack, a low air pressure alarm is activated when_________ minutes of air is
left. - CORRECT ANSWER-5
Which part of the human body is the most vulnerable to allowing microorganisms to enter it? -
CORRECT ANSWER-Eyes
Records of actions taken to correct violations must be kept for a minimum of: - CORRECT ANSWER-3
years
For surface water systems without filtration, the Surface Water Treatment Rule requires public
water systems to: - CORRECT ANSWER-Maintain a C x T value above the minimum value
200 QUESTIONS AND CORRECT ANSWERS/ WATER
TREATMENT OPERATOR IN TRAINING PRACTICE TEST
LATEST 2025/2026 (NEWEST!)
What is used as a chemical coagulant? - CORRECT ANSWER-Alum
The correct order of treatment in a surface water plant is... - CORRECT ANSWER-Coagulation,
Flocculation, Sedimentation and Filtration
When should polyphosphates used for sequestration of iron and manganese from a well be injected
into the process? - CORRECT ANSWER-Right after the water leaves the well
Recarbonation is: - CORRECT ANSWER-Adding CO2 to the water
In the ion-exchange softening process, once the resin can no longer soften water it must be: -
CORRECT ANSWER-Regenerated
What should be used by an operator to test for residual chlorine? - CORRECT ANSWER-DPD (N, N-
diethyl-p-phenylenediamine)
What is a major part of a turbidimeter? - CORRECT ANSWER-Light source
pH is a measure of: - CORRECT ANSWER-Hydrogen ion concentration
What is used to indicate the clarity of water? - CORRECT ANSWER-Turbidity
After chlorination, the free chlorine residual includes: - CORRECT ANSWER-OCI- and HOC1
Under no circumstances should a composite sample be collected for which type of analysis? -
CORRECT ANSWER-Bacteriological
The number of monthly distribution system chlorine residual samples required is: - CORRECT
ANSWER-Based on population
,When one substance is dissolved in another and will not settle out, what is it called? - CORRECT
ANSWER-A solution
What is a compound that is not derived from hydrocarbons? - CORRECT ANSWER-Inorganic
compound
After initial full-service operation, grease-lubricated bearings should be regreased at what
frequency? - CORRECT ANSWER-3 to 6 months
Check valves are used to prevent? - CORRECT ANSWER-Water from flowing in two directions
If a pump is run on a regular basis, packing should be inspected: - CORRECT ANSWER-Annually
What is a function of couplings? - CORRECT ANSWER-Compensate for alignment changes
What is the correct formula for determining watts> - CORRECT ANSWER-Watts= (amps)(volts)
The main purpose of a mechanical seal is to: - CORRECT ANSWER-Keep lubrication in and dirt and
other foreign materials out
The purpose of packing is to: - CORRECT ANSWER-Control water leakage along the pump's shaft
What part of a pump houses the packing or mechanical seal? - CORRECT ANSWER-The stuffing box
What type of pump can be operated against a closed valve? - CORRECT ANSWER-Centrifugal pump
What is a principal problem associated with preliminary treatment screening? - CORRECT ANSWER-
Clogging
Opening the discharge valve one full turn on a chlorine cylinder will: - CORRECT ANSWER-Permit
maximum discharge
, Tubercles can form on which type of pipe? - CORRECT ANSWER-Ductile iron
What is a primary indicator of bearing failure? - CORRECT ANSWER-Noise from pump
What disease is capable of being transmitted by water? - CORRECT ANSWER-Typhoid
When any piece of electrical equipment is being worked on, the circuit breaker should be: -
CORRECT ANSWER-De-energized and locked out
Which of the following directly impacts the treatment of drinking water?
A. Fair Labor Standards Act
B. Food Security Act
C. Safe Drinking Water Act
D. Clean Air Act - CORRECT ANSWER-C. Safe Drinking Water Act
Corrosive water acting on a customer's plumbing may cause what metal to enter their drinking
water? - CORRECT ANSWER-Lead
What is the most important thing to consider in automatic startup after a power failure? - CORRECT
ANSWER-Operator Safety
On a 30 minute SCBA air pack, a low air pressure alarm is activated when_________ minutes of air is
left. - CORRECT ANSWER-5
Which part of the human body is the most vulnerable to allowing microorganisms to enter it? -
CORRECT ANSWER-Eyes
Records of actions taken to correct violations must be kept for a minimum of: - CORRECT ANSWER-3
years
For surface water systems without filtration, the Surface Water Treatment Rule requires public
water systems to: - CORRECT ANSWER-Maintain a C x T value above the minimum value
