Texas Class B Wastewater Operator License Exam
2026 Preparation Guide: Comprehensive Review with
184 Textbook-Based Practice Questions and Verified
Correct Answers
The name of the State Agency responsible for enforcing pollution control laws in Texas -
Answer - Texas Commission of Environmental Quality
The term pathogenic means - Answer - Capable of causing disease
The minimum separation between sewer lines and potable water lines is - Answer - 9 feet
A licensed wastewater operator is a professional - Answer - consistently does best job possible,
practices personal safety, strives to improve job knowledge, strives to keep the plant and
collection system in the best appearance and working order
An important step in testing a sample for Total Suspended Solids is - Answer - Filtering a sample
The Biochemical oxygen Demand (BOD) of a sample is based on - Answer - Measuring the
dissolved oxygen (DO) used
The results of Biochemical Oxygen Demand (BOD) sample taken at a treatment plant tells the
operator - Answer - How the plant was operating 5 days ago
Which of the following are dangerous gasses that are likely to be present in lift stations and
manholes? - Answer - Natural gas, gasoline fumes, hydrogen sulfide and carbon dioxide
A preferred hydraulic method of cleaning sewer lines is - Answer - Hydro Jet Cleaner
,This trickling filter problem could be reduced by increasing the recirculation ratio - Answer -
Filter files
What gases are produced by the controlled anaerobic digestion of wastewater sludge's - Answer -
Methane & Carbon Dioxide
These diseases are caused by pathogenic organisms that may be present in raw wastewater -
Answer - Hepatitis, typhoid, paratyphoid,dysentery, cholera, gastroenteritis, polio, hookworm
and giardiasis
During heavy rain it is possible that manholes and lift stations may overflow, discharge waste
materials into roadways or ditches. This type of discharge (SSO) would be - Answer - considered
an unavoidable discharge, a violation of the Texas Water Code, a bypass that must be reported
within 24 hours and considered a health hazard
An effective way for the collection system worker to prevent infection by waterborn pathogenic
organism is to - Answer - Wear protective clothing and avoid direct contact with waste water
_________will increase the chances that sewage will turn septic - Answer - Stoppages in the
main line
Extensive use of garbage disposals (grinders) in a community would likely have the following
effect on the collection system - Answer - Increase the amount of flow, solids, and grease
The minimum size for a gravity flow sewer line on city right-of-way and the minimum grade is -
Answer - 6 inch and a grade of 0.50 percent
The most accurate way to find the average wastewater flow rate in an existing 10-inch sewer
main is - Answer - Obtaining actual flow data & verifying with field data
What is the greatest advantage for using fiberglass manholes in areas with high groundwater? -
Answer - fiberglass is not subject to infiltration
, A __________ pump would most likely be used when discharging into a 10" diameter pressure
sewer main. - Answer - Centrifugal
Excessive power consumption by a pump could be caused by - Answer - Worn bearings and
worn impeller
Trench safety is a great concern in Texas. OSHA requires that anytime an excavation is greater
than __ feet deep it must be protected by ______. - Answer - 5 feet / An approved Trench Box,
Shoring, or Sloping
In an excavation if a ladder is used as a means of exit, it must extend ________feet above the
ground and be secured and within ____ feet laterally of anyone in the excavation. - Answer - 3
feet / 25 feet laterally
A ____________ would be the best to determine if a storm drain is connected to a sanitary sewer
line. - Answer - Smoke Test
_________ would most commonly be used to seal a number of joint leaks on a main with
minimal interruption - Answer - internal grouting
Pre-treatment of wastewater would include: - Answer - Coarse or fine screening, grinding and
grit removal and grease removal and pre-aeration
Primary treatment of wastewater would include - Answer - settling tanks or basins, scum
collection and removal, sludge collection and removal
Secondary treatment typically used today would include - Answer - Stabilization ponds, trickling
filters, rotating biological contractors (RBC) & activated sludge
Essential components of the wastewater collection system include - Answer - Sewer mains &
piping, Lift Stations, Pumps, Grease & Sand traps, & Manholes
2026 Preparation Guide: Comprehensive Review with
184 Textbook-Based Practice Questions and Verified
Correct Answers
The name of the State Agency responsible for enforcing pollution control laws in Texas -
Answer - Texas Commission of Environmental Quality
The term pathogenic means - Answer - Capable of causing disease
The minimum separation between sewer lines and potable water lines is - Answer - 9 feet
A licensed wastewater operator is a professional - Answer - consistently does best job possible,
practices personal safety, strives to improve job knowledge, strives to keep the plant and
collection system in the best appearance and working order
An important step in testing a sample for Total Suspended Solids is - Answer - Filtering a sample
The Biochemical oxygen Demand (BOD) of a sample is based on - Answer - Measuring the
dissolved oxygen (DO) used
The results of Biochemical Oxygen Demand (BOD) sample taken at a treatment plant tells the
operator - Answer - How the plant was operating 5 days ago
Which of the following are dangerous gasses that are likely to be present in lift stations and
manholes? - Answer - Natural gas, gasoline fumes, hydrogen sulfide and carbon dioxide
A preferred hydraulic method of cleaning sewer lines is - Answer - Hydro Jet Cleaner
,This trickling filter problem could be reduced by increasing the recirculation ratio - Answer -
Filter files
What gases are produced by the controlled anaerobic digestion of wastewater sludge's - Answer -
Methane & Carbon Dioxide
These diseases are caused by pathogenic organisms that may be present in raw wastewater -
Answer - Hepatitis, typhoid, paratyphoid,dysentery, cholera, gastroenteritis, polio, hookworm
and giardiasis
During heavy rain it is possible that manholes and lift stations may overflow, discharge waste
materials into roadways or ditches. This type of discharge (SSO) would be - Answer - considered
an unavoidable discharge, a violation of the Texas Water Code, a bypass that must be reported
within 24 hours and considered a health hazard
An effective way for the collection system worker to prevent infection by waterborn pathogenic
organism is to - Answer - Wear protective clothing and avoid direct contact with waste water
_________will increase the chances that sewage will turn septic - Answer - Stoppages in the
main line
Extensive use of garbage disposals (grinders) in a community would likely have the following
effect on the collection system - Answer - Increase the amount of flow, solids, and grease
The minimum size for a gravity flow sewer line on city right-of-way and the minimum grade is -
Answer - 6 inch and a grade of 0.50 percent
The most accurate way to find the average wastewater flow rate in an existing 10-inch sewer
main is - Answer - Obtaining actual flow data & verifying with field data
What is the greatest advantage for using fiberglass manholes in areas with high groundwater? -
Answer - fiberglass is not subject to infiltration
, A __________ pump would most likely be used when discharging into a 10" diameter pressure
sewer main. - Answer - Centrifugal
Excessive power consumption by a pump could be caused by - Answer - Worn bearings and
worn impeller
Trench safety is a great concern in Texas. OSHA requires that anytime an excavation is greater
than __ feet deep it must be protected by ______. - Answer - 5 feet / An approved Trench Box,
Shoring, or Sloping
In an excavation if a ladder is used as a means of exit, it must extend ________feet above the
ground and be secured and within ____ feet laterally of anyone in the excavation. - Answer - 3
feet / 25 feet laterally
A ____________ would be the best to determine if a storm drain is connected to a sanitary sewer
line. - Answer - Smoke Test
_________ would most commonly be used to seal a number of joint leaks on a main with
minimal interruption - Answer - internal grouting
Pre-treatment of wastewater would include: - Answer - Coarse or fine screening, grinding and
grit removal and grease removal and pre-aeration
Primary treatment of wastewater would include - Answer - settling tanks or basins, scum
collection and removal, sludge collection and removal
Secondary treatment typically used today would include - Answer - Stabilization ponds, trickling
filters, rotating biological contractors (RBC) & activated sludge
Essential components of the wastewater collection system include - Answer - Sewer mains &
piping, Lift Stations, Pumps, Grease & Sand traps, & Manholes
