TCEQ OSSF LICENSE EXAM STUDY GUIDE | QUESTIONS AND ANSWERS,
MATH FORMULAS, & SITE EVALUATION ANSWERS
1: What is the primary regulatory document for On-Site Sewage Facilities (OSSF) in Texas?
A. Texas Water Code Chapter 50
B. Texas Administrative Code Title 30, Chapter 285
C. Texas Health and Safety Code Chapter 343
D. Texas Environmental Quality Act Title 15
CORRECT ANSWER: B. Texas Administrative Code Title 30, Chapter 285
Rationale: The Texas Commission on Environmental Quality (TCEQ) regulates OSSFs under Title
30 of the Texas Administrative Code, Chapter 285.
2: What does the acronym OSSF stand for?
A. On-Site Sewage Facility
B. Open System Sewage Filter
C. Official State Sanitation Fund
D. Organic Soil Separation Factor
CORRECT ANSWER: A. On-Site Sewage Facility
Rationale: OSSF is the official acronym used by the TCEQ for decentralized wastewater
treatment systems commonly known as septic systems.
3: Which TCEQ license class allows an individual to install all types of OSSFs, including
alternative systems?
A. Class I
B. Class III
C. Class V
D. Class A
CORRECT ANSWER: C. Class V
,Rationale: A Class V installer license permits the installation of all OSSFs, including complex
alternative systems and aerobic treatment units.
4: What is the minimum liquid depth required for a standard septic tank under TCEQ rules?
A. 2 feet
B. 3 feet
C. 4 feet
D. 6 feet
CORRECT ANSWER: C. 4 feet
Rationale: TCEQ rules require a minimum liquid depth of 4 feet in a septic tank to ensure
adequate retention time and separation of solids.
5: How many gallons of water are contained in one cubic foot?
A. 5.50 gallons
B. 6.24 gallons
C. 7.48 gallons
D. 8.34 gallons
CORRECT ANSWER: C. 7.48 gallons
Rationale: The standard conversion factor for water volume is 7.48 gallons per cubic foot.
6: What is the standard design flow rate per bedroom for a single-family residence in Texas?
A. 90 gallons per day
B. 120 gallons per day
C. 150 gallons per day
D. 200 gallons per day
CORRECT ANSWER: B. 120 gallons per day
,Rationale: TCEQ uses a standard design flow of 120 gallons per day per bedroom for calculating
the required size of OSSF components.
7: Which soil texture feels gritty when moist?
A. Clay
B. Silt
C. Sand
D. Loam
CORRECT ANSWER: C. Sand
Rationale: Sand particles are large enough to be felt individually, giving the soil a distinctly gritty
texture.
8: What is the maximum width allowed for a standard absorption trench?
A. 18 inches
B. 24 inches
C. 36 inches
D. 48 inches
CORRECT ANSWER: C. 36 inches
Rationale: TCEQ rules specify that the maximum width of an absorption trench is 36 inches to
ensure proper effluent distribution and soil contact.
9: What is the required minimum setback distance from a public water supply well to an OSSF
absorption field?
A. 25 feet
B. 50 feet
C. 75 feet
D. 100 feet
, CORRECT ANSWER: B. 50 feet
Rationale: To protect public drinking water sources, TCEQ mandates a minimum 50-foot
horizontal setback from a public water supply well.
10: Which tool is used to determine soil color during a site evaluation?
A. Hydrometer
B. Munsell Color Chart
C. Penetrometer
D. Secchi disk
CORRECT ANSWER: B. Munsell Color Chart
Rationale: The Munsell Color Chart is the standard tool used by soil evaluators to match and
record soil hue, value, and chroma.
11: What is the primary purpose of the inlet baffle or tee in a septic tank?
A. To prevent scum from escaping into the drainfield
B. To direct incoming wastewater below the surface of the scum layer
C. To mix the solids and liquids thoroughly
D. To allow gases to escape the tank
CORRECT ANSWER: B. To direct incoming wastewater below the surface of the scum layer
Rationale: The inlet baffle diverts incoming flow downward to prevent disturbing the scum layer
and short-circuiting the tank.
12: In a perc test, what is the required diameter of the test hole?
A. 2 to 4 inches
B. 6 to 8 inches
C. 10 to 12 inches
D. 14 to 16 inches
MATH FORMULAS, & SITE EVALUATION ANSWERS
1: What is the primary regulatory document for On-Site Sewage Facilities (OSSF) in Texas?
A. Texas Water Code Chapter 50
B. Texas Administrative Code Title 30, Chapter 285
C. Texas Health and Safety Code Chapter 343
D. Texas Environmental Quality Act Title 15
CORRECT ANSWER: B. Texas Administrative Code Title 30, Chapter 285
Rationale: The Texas Commission on Environmental Quality (TCEQ) regulates OSSFs under Title
30 of the Texas Administrative Code, Chapter 285.
2: What does the acronym OSSF stand for?
A. On-Site Sewage Facility
B. Open System Sewage Filter
C. Official State Sanitation Fund
D. Organic Soil Separation Factor
CORRECT ANSWER: A. On-Site Sewage Facility
Rationale: OSSF is the official acronym used by the TCEQ for decentralized wastewater
treatment systems commonly known as septic systems.
3: Which TCEQ license class allows an individual to install all types of OSSFs, including
alternative systems?
A. Class I
B. Class III
C. Class V
D. Class A
CORRECT ANSWER: C. Class V
,Rationale: A Class V installer license permits the installation of all OSSFs, including complex
alternative systems and aerobic treatment units.
4: What is the minimum liquid depth required for a standard septic tank under TCEQ rules?
A. 2 feet
B. 3 feet
C. 4 feet
D. 6 feet
CORRECT ANSWER: C. 4 feet
Rationale: TCEQ rules require a minimum liquid depth of 4 feet in a septic tank to ensure
adequate retention time and separation of solids.
5: How many gallons of water are contained in one cubic foot?
A. 5.50 gallons
B. 6.24 gallons
C. 7.48 gallons
D. 8.34 gallons
CORRECT ANSWER: C. 7.48 gallons
Rationale: The standard conversion factor for water volume is 7.48 gallons per cubic foot.
6: What is the standard design flow rate per bedroom for a single-family residence in Texas?
A. 90 gallons per day
B. 120 gallons per day
C. 150 gallons per day
D. 200 gallons per day
CORRECT ANSWER: B. 120 gallons per day
,Rationale: TCEQ uses a standard design flow of 120 gallons per day per bedroom for calculating
the required size of OSSF components.
7: Which soil texture feels gritty when moist?
A. Clay
B. Silt
C. Sand
D. Loam
CORRECT ANSWER: C. Sand
Rationale: Sand particles are large enough to be felt individually, giving the soil a distinctly gritty
texture.
8: What is the maximum width allowed for a standard absorption trench?
A. 18 inches
B. 24 inches
C. 36 inches
D. 48 inches
CORRECT ANSWER: C. 36 inches
Rationale: TCEQ rules specify that the maximum width of an absorption trench is 36 inches to
ensure proper effluent distribution and soil contact.
9: What is the required minimum setback distance from a public water supply well to an OSSF
absorption field?
A. 25 feet
B. 50 feet
C. 75 feet
D. 100 feet
, CORRECT ANSWER: B. 50 feet
Rationale: To protect public drinking water sources, TCEQ mandates a minimum 50-foot
horizontal setback from a public water supply well.
10: Which tool is used to determine soil color during a site evaluation?
A. Hydrometer
B. Munsell Color Chart
C. Penetrometer
D. Secchi disk
CORRECT ANSWER: B. Munsell Color Chart
Rationale: The Munsell Color Chart is the standard tool used by soil evaluators to match and
record soil hue, value, and chroma.
11: What is the primary purpose of the inlet baffle or tee in a septic tank?
A. To prevent scum from escaping into the drainfield
B. To direct incoming wastewater below the surface of the scum layer
C. To mix the solids and liquids thoroughly
D. To allow gases to escape the tank
CORRECT ANSWER: B. To direct incoming wastewater below the surface of the scum layer
Rationale: The inlet baffle diverts incoming flow downward to prevent disturbing the scum layer
and short-circuiting the tank.
12: In a perc test, what is the required diameter of the test hole?
A. 2 to 4 inches
B. 6 to 8 inches
C. 10 to 12 inches
D. 14 to 16 inches
