Texas On-Site Sewage Facility (OSSF) Installer I – TCEQ
Exam Prep questions & answers & rationale | 2025/2026 |
Latest Update| Instant download!!
1. What is the primary purpose of an on-site sewage facility (OSSF)?
A. Provide potable water
B. Safely treat and dispose of household wastewater (correct answer)
C. Increase water pressure
D. Reduce stormwater runoff
Rationale: OSSFs treat and dispose of wastewater from homes in areas without centralized sewer
systems.
2. Which of the following is NOT typically considered a component of a conventional septic
system?
A. Septic tank
B. Stormwater retention pond (correct answer)
C. Distribution lines
D. Soil absorption area
Rationale: Stormwater retention ponds are unrelated to sewage treatment.
3. What is the minimum distance a septic tank must be from a potable water well according to
TCEQ rules?
A. 10 feet
B. 25 feet
C. 50 feet (correct answer)
D. 100 feet
Rationale: TCEQ requires a 50-foot minimum distance to protect groundwater from contamination.
4. Which type of soil is considered most suitable for standard soil absorption systems?
A. Clay
B. Sand
C. Loam or sandy loam (correct answer)
D. Rocky soil
,Rationale: Loam or sandy loam soils allow proper percolation and treatment.
5. What is the primary function of the septic tank in an OSSF?
A. Filter drinking water
B. Settle solids and begin anaerobic digestion (correct answer)
C. Pump wastewater to the city
D. Provide an irrigation source
Rationale: Septic tanks separate solids from liquid effluent and partially treat the wastewater.
6. When inspecting a septic tank, which of the following indicates a problem?
A. Liquid level slightly below outlet
B. Excessive scum or sludge accumulation (correct answer)
C. Effluent flowing to absorption field
D. Tank covered with grass
Rationale: Too much scum or sludge reduces treatment capacity and may clog the drain field.
7. Which of the following is a common cause of OSSF failure?
A. Using treated effluent for irrigation
B. Proper maintenance
C. Excessive water use or soil saturation (correct answer)
D. Correct tank sizing
Rationale: Overloading the system can prevent proper treatment and disposal.
8. The standard retention time in a residential septic tank is typically:
A. 6 hours
B. 12 hours
C. 24–48 hours (correct answer)
D. 7 days
Rationale: Adequate retention allows solids to settle and begin anaerobic digestion.
9. Which of the following is an acceptable method of determining percolation rate for a soil
absorption system?
, A. Guessing based on soil color
B. Percolation (perc) test (correct answer)
C. Measuring rainfall
D. Observing vegetation
Rationale: Perc tests measure how quickly water drains through soil, determining system design.
10. What is the purpose of a distribution box in a conventional OSSF?
A. Pump water to the city
B. Evenly distribute effluent to absorption lines (correct answer)
C. Remove solids
D. Increase water pressure
Rationale: Distribution boxes prevent overloading one trench or field section.
11. Which of the following is required before installing an OSSF in Texas?
A. Purchase of tank only
B. TCEQ permit and site evaluation (correct answer)
C. Contractor license only
D. None
Rationale: Permits ensure compliance with state regulations and site suitability.
12. Which of the following best describes the function of a soil absorption field?
A. Filter drinking water
B. Provide final treatment and dispersal of effluent into the soil (correct answer)
C. Pump water to surface
D. Retain solids
Rationale: Soil absorption fields treat effluent biologically and physically as it percolates through
soil.
13. Which of the following is a sign of hydraulic overload in an OSSF?
A. Flow into the field is consistent
B. Effluent surfacing on the ground (correct answer)
C. Tank fully covered with grass
D. Distribution box level is normal
Exam Prep questions & answers & rationale | 2025/2026 |
Latest Update| Instant download!!
1. What is the primary purpose of an on-site sewage facility (OSSF)?
A. Provide potable water
B. Safely treat and dispose of household wastewater (correct answer)
C. Increase water pressure
D. Reduce stormwater runoff
Rationale: OSSFs treat and dispose of wastewater from homes in areas without centralized sewer
systems.
2. Which of the following is NOT typically considered a component of a conventional septic
system?
A. Septic tank
B. Stormwater retention pond (correct answer)
C. Distribution lines
D. Soil absorption area
Rationale: Stormwater retention ponds are unrelated to sewage treatment.
3. What is the minimum distance a septic tank must be from a potable water well according to
TCEQ rules?
A. 10 feet
B. 25 feet
C. 50 feet (correct answer)
D. 100 feet
Rationale: TCEQ requires a 50-foot minimum distance to protect groundwater from contamination.
4. Which type of soil is considered most suitable for standard soil absorption systems?
A. Clay
B. Sand
C. Loam or sandy loam (correct answer)
D. Rocky soil
,Rationale: Loam or sandy loam soils allow proper percolation and treatment.
5. What is the primary function of the septic tank in an OSSF?
A. Filter drinking water
B. Settle solids and begin anaerobic digestion (correct answer)
C. Pump wastewater to the city
D. Provide an irrigation source
Rationale: Septic tanks separate solids from liquid effluent and partially treat the wastewater.
6. When inspecting a septic tank, which of the following indicates a problem?
A. Liquid level slightly below outlet
B. Excessive scum or sludge accumulation (correct answer)
C. Effluent flowing to absorption field
D. Tank covered with grass
Rationale: Too much scum or sludge reduces treatment capacity and may clog the drain field.
7. Which of the following is a common cause of OSSF failure?
A. Using treated effluent for irrigation
B. Proper maintenance
C. Excessive water use or soil saturation (correct answer)
D. Correct tank sizing
Rationale: Overloading the system can prevent proper treatment and disposal.
8. The standard retention time in a residential septic tank is typically:
A. 6 hours
B. 12 hours
C. 24–48 hours (correct answer)
D. 7 days
Rationale: Adequate retention allows solids to settle and begin anaerobic digestion.
9. Which of the following is an acceptable method of determining percolation rate for a soil
absorption system?
, A. Guessing based on soil color
B. Percolation (perc) test (correct answer)
C. Measuring rainfall
D. Observing vegetation
Rationale: Perc tests measure how quickly water drains through soil, determining system design.
10. What is the purpose of a distribution box in a conventional OSSF?
A. Pump water to the city
B. Evenly distribute effluent to absorption lines (correct answer)
C. Remove solids
D. Increase water pressure
Rationale: Distribution boxes prevent overloading one trench or field section.
11. Which of the following is required before installing an OSSF in Texas?
A. Purchase of tank only
B. TCEQ permit and site evaluation (correct answer)
C. Contractor license only
D. None
Rationale: Permits ensure compliance with state regulations and site suitability.
12. Which of the following best describes the function of a soil absorption field?
A. Filter drinking water
B. Provide final treatment and dispersal of effluent into the soil (correct answer)
C. Pump water to surface
D. Retain solids
Rationale: Soil absorption fields treat effluent biologically and physically as it percolates through
soil.
13. Which of the following is a sign of hydraulic overload in an OSSF?
A. Flow into the field is consistent
B. Effluent surfacing on the ground (correct answer)
C. Tank fully covered with grass
D. Distribution box level is normal
