LEVEL 1 WATER DISTRIBUTION PRACTICE TEST 200 PRACTICE
QUESTIONS COMPLETE WITH VERIFIED ANSWERS
1. What are the two main sources of drinking water?
A) Rivers and lakes only
B) Surface water and groundwater
C) Wells and reservoirs
D) Precipitation and runoff
Answer: B
Rationale: The two main sources of drinking water are surface water
(rivers, lakes, reservoirs) and groundwater (wells, aquifers).
2. The minimum and maximum free chlorine residual in a water
distribution system is:
A) 0.1 mg/L and 2.0 mg/L
B) 0.5 mg/L and 5.0 mg/L
C) 0.2 mg/L and 4.0 mg/L
D) 1.0 mg/L and 10.0 mg/L
Answer: C
Rationale: The acceptable free chlorine residual range is 0.2 mg/L
minimum to maintain disinfection and 4.0 mg/L maximum to avoid
taste and odor issues.
,3. Nitrate may not exceed what concentration when tested yearly for
a groundwater treatment plant?
A) 5 mg/L
B) 15 mg/L
C) 20 mg/L
D) 10 mg/L
Answer: D
Rationale: The Maximum Contaminant Level (MCL) for nitrate in
drinking water is 10 mg/L as measured as nitrogen, protecting against
methemoglobinemia.
4. The minimum number of total coliform samples that must be
collected per month is based on:
A) The number of wells in operation
B) The population served by the system
C) The total miles of pipeline
D) The system's average daily flow
Answer: B
Rationale: The Safe Drinking Water Act requires monthly coliform
sampling based on the population served. Larger populations require
more samples.
5. What is the normal pH range for drinking water?
A) 4.0-6.0
B) 5.5-7.5
,C) 7.0-9.0
D) 6.5-8.5
Answer: D
Rationale: The normal pH range for drinking water is 6.5-8.5. Water
below 6.5 can be corrosive, while above 8.5 may have taste issues.
6. When a distribution bacteriological sample is positive for total
coliform, the procedure is:
A) Collect one repeat sample from the same location only
B) Immediately issue a boil water notice
C) Repeat the sample and take samples 5 connections upstream and
downstream to confirm
D) Flush the line and resample the next day
Answer: C
Rationale: When a sample is positive for total coliform, repeat samples
must be taken from the original location and 5 connections upstream
and downstream to confirm contamination.
7. For lead and copper sampling, the water must remain in the
pipeline for at least:
A) 2 hours
B) 4 hours
C) 6 hours
D) 8 hours
, Answer: C
Rationale: Lead and copper samples require a minimum stagnation time
of 6 hours in the pipeline to accurately reflect metal concentrations.
8. What is a hydraulic grade line?
A) The pressure at the highest point in a system
B) A line to which water would rise in a small vertical tube connected to
the pipe
C) The elevation of the water surface in a storage tank
D) The total energy line including velocity head
Answer: B
Rationale: The hydraulic grade line represents the level to which water
would rise in a piezometer tube connected to the pipe.
9. How often should cathodic protection anodes in a water system be
inspected?
A) Every month
B) Every 6 months
C) Every year
D) Every 2 years
Answer: C
Rationale: Cathodic protection anodes should be inspected annually to
ensure they are functioning properly and providing adequate corrosion
protection.
QUESTIONS COMPLETE WITH VERIFIED ANSWERS
1. What are the two main sources of drinking water?
A) Rivers and lakes only
B) Surface water and groundwater
C) Wells and reservoirs
D) Precipitation and runoff
Answer: B
Rationale: The two main sources of drinking water are surface water
(rivers, lakes, reservoirs) and groundwater (wells, aquifers).
2. The minimum and maximum free chlorine residual in a water
distribution system is:
A) 0.1 mg/L and 2.0 mg/L
B) 0.5 mg/L and 5.0 mg/L
C) 0.2 mg/L and 4.0 mg/L
D) 1.0 mg/L and 10.0 mg/L
Answer: C
Rationale: The acceptable free chlorine residual range is 0.2 mg/L
minimum to maintain disinfection and 4.0 mg/L maximum to avoid
taste and odor issues.
,3. Nitrate may not exceed what concentration when tested yearly for
a groundwater treatment plant?
A) 5 mg/L
B) 15 mg/L
C) 20 mg/L
D) 10 mg/L
Answer: D
Rationale: The Maximum Contaminant Level (MCL) for nitrate in
drinking water is 10 mg/L as measured as nitrogen, protecting against
methemoglobinemia.
4. The minimum number of total coliform samples that must be
collected per month is based on:
A) The number of wells in operation
B) The population served by the system
C) The total miles of pipeline
D) The system's average daily flow
Answer: B
Rationale: The Safe Drinking Water Act requires monthly coliform
sampling based on the population served. Larger populations require
more samples.
5. What is the normal pH range for drinking water?
A) 4.0-6.0
B) 5.5-7.5
,C) 7.0-9.0
D) 6.5-8.5
Answer: D
Rationale: The normal pH range for drinking water is 6.5-8.5. Water
below 6.5 can be corrosive, while above 8.5 may have taste issues.
6. When a distribution bacteriological sample is positive for total
coliform, the procedure is:
A) Collect one repeat sample from the same location only
B) Immediately issue a boil water notice
C) Repeat the sample and take samples 5 connections upstream and
downstream to confirm
D) Flush the line and resample the next day
Answer: C
Rationale: When a sample is positive for total coliform, repeat samples
must be taken from the original location and 5 connections upstream
and downstream to confirm contamination.
7. For lead and copper sampling, the water must remain in the
pipeline for at least:
A) 2 hours
B) 4 hours
C) 6 hours
D) 8 hours
, Answer: C
Rationale: Lead and copper samples require a minimum stagnation time
of 6 hours in the pipeline to accurately reflect metal concentrations.
8. What is a hydraulic grade line?
A) The pressure at the highest point in a system
B) A line to which water would rise in a small vertical tube connected to
the pipe
C) The elevation of the water surface in a storage tank
D) The total energy line including velocity head
Answer: B
Rationale: The hydraulic grade line represents the level to which water
would rise in a piezometer tube connected to the pipe.
9. How often should cathodic protection anodes in a water system be
inspected?
A) Every month
B) Every 6 months
C) Every year
D) Every 2 years
Answer: C
Rationale: Cathodic protection anodes should be inspected annually to
ensure they are functioning properly and providing adequate corrosion
protection.
