TEXAS WASTEWATER CLASS A EXAM
PRACTICE QUESTIONS WITH ANSWERS
& RATIONALES
Question 1: According to TCEQ Design Criteria, a manhole can be installed
within 9 feet of an existing waterline under what condition?
A) The manhole is located downstream of the waterline
B) The manhole is completely watertight and tested for no leakage
C) The waterline is made of ductile iron
D) The manhole is at least 4 feet in diameter
Correct Answer: B) The manhole is completely watertight and tested
for no leakage
Rationale: According to TCEQ Design Criteria (Chapter 317), a manhole can
be installed within 9 feet of an existing waterline if the manhole is completely
watertight and tested for no leakage. This prevents contamination of the
water supply from wastewater infiltration.
Question 2: What are the minimum design criteria for force main
wastewater lines in Texas?
A) Minimum 1 fps velocity, 2-inch diameter pipe, 100 psi rating
B) Minimum 2 fps velocity with the smallest pump operating alone, 4-inch
diameter pipe, 150 psi rating
C) Minimum 3 fps velocity, 6-inch diameter pipe, 200 psi rating
D) Minimum 2 fps velocity, 6-inch diameter pipe, 100 psi rating
Correct Answer: B) Minimum 2 fps velocity with the smallest pump
operating alone, 4-inch diameter pipe, 150 psi rating
,Rationale: Force main wastewater lines must be designed with a minimum
velocity of 2 fps when the smallest pump is operating alone to prevent solids
deposition. The minimum pipe diameter is 4 inches with a pressure rating of
150 psi.
Question 3: The TCEQ Design Criteria requires that deflection tests be
performed on all newly installed flexible or semi-rigid pipe. What diameter
rigid ball or mandrel is used for this test?
A) 85% of the inside diameter of the pipe
B) 90% of the inside diameter of the pipe
C) 95% of the inside diameter of the pipe
D) 100% of the inside diameter of the pipe
Correct Answer: C) 95% of the inside diameter of the pipe
Rationale: Deflection tests are performed using a rigid ball or mandrel with a
diameter equal to 95% of the inside diameter of the pipe. The test is
conducted after the final backfill has been in place for 30 days to verify that
the pipe has not deformed excessively.
Question 4: What is the minimum velocity required for gravity wastewater
lines under normal flow conditions?
A) 1.0 fps
B) 2.0 fps
C) 3.0 fps
D) 5.0 fps
Correct Answer: B) 2.0 fps
,Rationale: Gravity wastewater lines must be designed to flow half-full under
normal conditions at a minimum velocity of 2.0 fps to maintain self-cleansing
action and prevent solids deposition. The maximum velocity is 10 fps to
prevent erosion.
Question 5: What is the minimum diameter for a manhole opening
according to TCEQ standards?
A) 18 inches
B) 20 inches
C) 22 inches
D) 24 inches
Correct Answer: D) 24 inches
Rationale: Manholes must have a minimum opening of 24 inches and be at
least 4 feet wide to allow for safe entry and maintenance access.
Question 6: As the population of a collection system increases, what
happens to the ratio of peak flow to average daily flow?
A) It increases proportionally
B) It decreases
C) It remains constant
D) It fluctuates randomly
Correct Answer: B) It decreases
Rationale: As the population served by a collection system increases, the ratio
of peak flow to average daily flow decreases. This is because the larger
population base smooths out diurnal flow variations.
, Question 7: In low pressure sewer systems where each tap must have a
grinder pump lift station, who is typically responsible for the station?
A) The homeowner
B) The developer
C) The utility
D) The contractor
Correct Answer: C) The utility
Rationale: In low pressure sewer systems, the grinder pump lift station is
considered to be part of the collection system and is the responsibility of the
utility.
Question 8: According to TCEQ, monitoring and reporting records of a
wastewater treatment plant shall be kept at the facility site for a period of:
A) 1 year
B) 2 years
C) 3 years
D) 5 years
Correct Answer: C) 3 years
Rationale: Wastewater treatment plant monitoring and reporting records
must be kept at the facility site for a period of three years. This ensures that
records are available for inspection by TCEQ personnel.
Question 9: What is Standard Dimension Ratio (SDR) in PVC pipe?
PRACTICE QUESTIONS WITH ANSWERS
& RATIONALES
Question 1: According to TCEQ Design Criteria, a manhole can be installed
within 9 feet of an existing waterline under what condition?
A) The manhole is located downstream of the waterline
B) The manhole is completely watertight and tested for no leakage
C) The waterline is made of ductile iron
D) The manhole is at least 4 feet in diameter
Correct Answer: B) The manhole is completely watertight and tested
for no leakage
Rationale: According to TCEQ Design Criteria (Chapter 317), a manhole can
be installed within 9 feet of an existing waterline if the manhole is completely
watertight and tested for no leakage. This prevents contamination of the
water supply from wastewater infiltration.
Question 2: What are the minimum design criteria for force main
wastewater lines in Texas?
A) Minimum 1 fps velocity, 2-inch diameter pipe, 100 psi rating
B) Minimum 2 fps velocity with the smallest pump operating alone, 4-inch
diameter pipe, 150 psi rating
C) Minimum 3 fps velocity, 6-inch diameter pipe, 200 psi rating
D) Minimum 2 fps velocity, 6-inch diameter pipe, 100 psi rating
Correct Answer: B) Minimum 2 fps velocity with the smallest pump
operating alone, 4-inch diameter pipe, 150 psi rating
,Rationale: Force main wastewater lines must be designed with a minimum
velocity of 2 fps when the smallest pump is operating alone to prevent solids
deposition. The minimum pipe diameter is 4 inches with a pressure rating of
150 psi.
Question 3: The TCEQ Design Criteria requires that deflection tests be
performed on all newly installed flexible or semi-rigid pipe. What diameter
rigid ball or mandrel is used for this test?
A) 85% of the inside diameter of the pipe
B) 90% of the inside diameter of the pipe
C) 95% of the inside diameter of the pipe
D) 100% of the inside diameter of the pipe
Correct Answer: C) 95% of the inside diameter of the pipe
Rationale: Deflection tests are performed using a rigid ball or mandrel with a
diameter equal to 95% of the inside diameter of the pipe. The test is
conducted after the final backfill has been in place for 30 days to verify that
the pipe has not deformed excessively.
Question 4: What is the minimum velocity required for gravity wastewater
lines under normal flow conditions?
A) 1.0 fps
B) 2.0 fps
C) 3.0 fps
D) 5.0 fps
Correct Answer: B) 2.0 fps
,Rationale: Gravity wastewater lines must be designed to flow half-full under
normal conditions at a minimum velocity of 2.0 fps to maintain self-cleansing
action and prevent solids deposition. The maximum velocity is 10 fps to
prevent erosion.
Question 5: What is the minimum diameter for a manhole opening
according to TCEQ standards?
A) 18 inches
B) 20 inches
C) 22 inches
D) 24 inches
Correct Answer: D) 24 inches
Rationale: Manholes must have a minimum opening of 24 inches and be at
least 4 feet wide to allow for safe entry and maintenance access.
Question 6: As the population of a collection system increases, what
happens to the ratio of peak flow to average daily flow?
A) It increases proportionally
B) It decreases
C) It remains constant
D) It fluctuates randomly
Correct Answer: B) It decreases
Rationale: As the population served by a collection system increases, the ratio
of peak flow to average daily flow decreases. This is because the larger
population base smooths out diurnal flow variations.
, Question 7: In low pressure sewer systems where each tap must have a
grinder pump lift station, who is typically responsible for the station?
A) The homeowner
B) The developer
C) The utility
D) The contractor
Correct Answer: C) The utility
Rationale: In low pressure sewer systems, the grinder pump lift station is
considered to be part of the collection system and is the responsibility of the
utility.
Question 8: According to TCEQ, monitoring and reporting records of a
wastewater treatment plant shall be kept at the facility site for a period of:
A) 1 year
B) 2 years
C) 3 years
D) 5 years
Correct Answer: C) 3 years
Rationale: Wastewater treatment plant monitoring and reporting records
must be kept at the facility site for a period of three years. This ensures that
records are available for inspection by TCEQ personnel.
Question 9: What is Standard Dimension Ratio (SDR) in PVC pipe?
