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Wastewater Class B License Exam 2026 Prep
150 Questions & Answers with Detailed
Rationales
Instructions: Select the best answer for each question. These
questions are designed to reflect the actual content and
difficulty level of state wastewater operator certification
examinations for Class B licensure. Topics covered include
regulations, safety, collection systems, preliminary
treatment, primary treatment, secondary treatment
(activated sludge, trickling filters), disinfection, solids
handling, laboratory procedures, and process control
calculations.
SECTION I: REGULATIONS & ADMINISTRATION (Questions 1-15)
1. The primary federal law that regulates the discharge of pollutants
into waters of the United States is the:
A. Safe Drinking Water Act (SDWA)
B. Clean Water Act (CWA)
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C. Resource Conservation and Recovery Act (RCRA)
D. Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA)
Answer: B
Rationale: The Clean Water Act (CWA) is the primary federal
law governing water pollution. It establishes the structure for
regulating pollutant discharges into US waters and quality
standards for surface waters. The SDWA regulates drinking
water, RCRA governs solid/hazardous waste, and CERCLA
addresses hazardous waste sites (Superfund).
2. The National Pollutant Discharge Elimination System (NPDES)
permit program controls discharges by setting limits on:
A. Air emissions from treatment plants
B. Groundwater withdrawals
C. Point source discharges to surface waters
D. Solid waste disposal methods
Answer: C
Rationale: NPDES permits regulate point source discharges
(discrete conveyances such as pipes or ditches) to surface
waters. Permits contain limits on pollutants, monitoring
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requirements, and reporting obligations. This is a core
concept of the Clean Water Act.
3. A community water system has how many years to comply with
the PFAS National Primary Drinking Water Regulation finalized in
April 2024?
A. 1 year
B. 2 years
C. 3 years
D. 5 years
Answer: D
Rationale: The EPA gave community water systems five years
to comply with the PFAS regulation due to the significant
investments required for treatment plant upgrades and
infrastructure modifications. This timeline acknowledges the
complexity of PFAS removal technology implementation.
4. The minimum separation distance required between a new
sanitary sewer line and a potable water line is typically:
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A. 3 feet
B. 5 feet
C. 9 feet
D. 12 feet
Answer: C
Rationale: Standard construction requirements specify a
minimum 9-foot separation between sewer lines and potable
water lines to prevent contamination of drinking water
supplies in the event of a leak or break in either line. Local
codes may vary but 9 feet is the industry standard.
5. A newly hired wastewater operator in Texas has how long to
become licensed?
A. 3 months
B. 6 months
C. 1 year
D. 2 years
Answer: C
Rationale: Newly hired personnel typically have one year to obtain
the required license. This allows time for on-the-job training and
Wastewater Class B License Exam 2026 Prep
150 Questions & Answers with Detailed
Rationales
Instructions: Select the best answer for each question. These
questions are designed to reflect the actual content and
difficulty level of state wastewater operator certification
examinations for Class B licensure. Topics covered include
regulations, safety, collection systems, preliminary
treatment, primary treatment, secondary treatment
(activated sludge, trickling filters), disinfection, solids
handling, laboratory procedures, and process control
calculations.
SECTION I: REGULATIONS & ADMINISTRATION (Questions 1-15)
1. The primary federal law that regulates the discharge of pollutants
into waters of the United States is the:
A. Safe Drinking Water Act (SDWA)
B. Clean Water Act (CWA)
,2|Page
C. Resource Conservation and Recovery Act (RCRA)
D. Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA)
Answer: B
Rationale: The Clean Water Act (CWA) is the primary federal
law governing water pollution. It establishes the structure for
regulating pollutant discharges into US waters and quality
standards for surface waters. The SDWA regulates drinking
water, RCRA governs solid/hazardous waste, and CERCLA
addresses hazardous waste sites (Superfund).
2. The National Pollutant Discharge Elimination System (NPDES)
permit program controls discharges by setting limits on:
A. Air emissions from treatment plants
B. Groundwater withdrawals
C. Point source discharges to surface waters
D. Solid waste disposal methods
Answer: C
Rationale: NPDES permits regulate point source discharges
(discrete conveyances such as pipes or ditches) to surface
waters. Permits contain limits on pollutants, monitoring
,3|Page
requirements, and reporting obligations. This is a core
concept of the Clean Water Act.
3. A community water system has how many years to comply with
the PFAS National Primary Drinking Water Regulation finalized in
April 2024?
A. 1 year
B. 2 years
C. 3 years
D. 5 years
Answer: D
Rationale: The EPA gave community water systems five years
to comply with the PFAS regulation due to the significant
investments required for treatment plant upgrades and
infrastructure modifications. This timeline acknowledges the
complexity of PFAS removal technology implementation.
4. The minimum separation distance required between a new
sanitary sewer line and a potable water line is typically:
, 4|Page
A. 3 feet
B. 5 feet
C. 9 feet
D. 12 feet
Answer: C
Rationale: Standard construction requirements specify a
minimum 9-foot separation between sewer lines and potable
water lines to prevent contamination of drinking water
supplies in the event of a leak or break in either line. Local
codes may vary but 9 feet is the industry standard.
5. A newly hired wastewater operator in Texas has how long to
become licensed?
A. 3 months
B. 6 months
C. 1 year
D. 2 years
Answer: C
Rationale: Newly hired personnel typically have one year to obtain
the required license. This allows time for on-the-job training and
