Texas OSSF Installer II EXAM TEST QUESTIONS AND
CORRECT ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2026 |INSTANT DOWNLOAD PDF
1. Which agency regulates On-Site Sewage Facilities (OSSFs) in
Texas?
A. EPA
B. CDC
C. TCEQ
D. USDA
*Correct Answer: C — The Texas Commission on Environmental
Quality (TCEQ) oversees OSSF regulations, licensing, and
compliance.
2. Installer II certification allows installation of which systems?
A. Standard septic only
B. Holding tanks only
C. All permitted OSSF systems
D. Graywater systems only
*Correct Answer: C — Installer II may install all OSSF types
permitted by TCEQ, including aerobic and advanced treatment
systems.
3. Minimum liquid capacity of a septic tank for a 3-bedroom
house is:
A. 500 gallons
B. 750 gallons
,C. 1,000 gallons
D. 1,250 gallons
*Correct Answer: C — Texas rules require at least 1,000 gallons
to provide adequate retention time for solids and treatment.
4. Which OSSF component removes most settleable solids?
A. Pump tank
B. Aerator
C. Septic tank
D. Spray head
*Correct Answer: C — The septic tank provides primary
treatment by allowing solids to settle.
5. Soil texture primarily affects which system design factor?
A. Pipe diameter
B. Tank material
C. Absorption rate
D. Electrical load
*Correct Answer: C — Soil type determines how quickly effluent
infiltrates the ground, affecting drainfield sizing.
6. Which soil type has the fastest percolation rate?
A. Clay
B. Silt
C. Loam
D. Sand
*Correct Answer: D — Sand has large pore spaces, allowing
rapid drainage and high infiltration rates.
, 7. Minimum setback from a private water well is:
A. 25 ft
B. 50 ft
C. 100 ft
D. 150 ft
*Correct Answer: C — TCEQ requires 100 feet to protect
groundwater sources from contamination.
8. What device prevents solids from entering the drainfield?
A. Check valve
B. Effluent filter
C. Air pump
D. Control panel
*Correct Answer: B — Effluent filters trap suspended solids to
prevent clogging of the drainfield.
9. Which system uses forced air to treat wastewater?
A. Conventional septic
B. Low-pressure dosing
C. Aerobic treatment unit (ATU)
D. Evapotranspiration bed
*Correct Answer: C — ATUs inject oxygen to promote microbial
breakdown of waste.
10. Installer II must ensure electrical components are:
A. Painted
B. Buried
C. Weatherproof and code-compliant
CORRECT ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2026 |INSTANT DOWNLOAD PDF
1. Which agency regulates On-Site Sewage Facilities (OSSFs) in
Texas?
A. EPA
B. CDC
C. TCEQ
D. USDA
*Correct Answer: C — The Texas Commission on Environmental
Quality (TCEQ) oversees OSSF regulations, licensing, and
compliance.
2. Installer II certification allows installation of which systems?
A. Standard septic only
B. Holding tanks only
C. All permitted OSSF systems
D. Graywater systems only
*Correct Answer: C — Installer II may install all OSSF types
permitted by TCEQ, including aerobic and advanced treatment
systems.
3. Minimum liquid capacity of a septic tank for a 3-bedroom
house is:
A. 500 gallons
B. 750 gallons
,C. 1,000 gallons
D. 1,250 gallons
*Correct Answer: C — Texas rules require at least 1,000 gallons
to provide adequate retention time for solids and treatment.
4. Which OSSF component removes most settleable solids?
A. Pump tank
B. Aerator
C. Septic tank
D. Spray head
*Correct Answer: C — The septic tank provides primary
treatment by allowing solids to settle.
5. Soil texture primarily affects which system design factor?
A. Pipe diameter
B. Tank material
C. Absorption rate
D. Electrical load
*Correct Answer: C — Soil type determines how quickly effluent
infiltrates the ground, affecting drainfield sizing.
6. Which soil type has the fastest percolation rate?
A. Clay
B. Silt
C. Loam
D. Sand
*Correct Answer: D — Sand has large pore spaces, allowing
rapid drainage and high infiltration rates.
, 7. Minimum setback from a private water well is:
A. 25 ft
B. 50 ft
C. 100 ft
D. 150 ft
*Correct Answer: C — TCEQ requires 100 feet to protect
groundwater sources from contamination.
8. What device prevents solids from entering the drainfield?
A. Check valve
B. Effluent filter
C. Air pump
D. Control panel
*Correct Answer: B — Effluent filters trap suspended solids to
prevent clogging of the drainfield.
9. Which system uses forced air to treat wastewater?
A. Conventional septic
B. Low-pressure dosing
C. Aerobic treatment unit (ATU)
D. Evapotranspiration bed
*Correct Answer: C — ATUs inject oxygen to promote microbial
breakdown of waste.
10. Installer II must ensure electrical components are:
A. Painted
B. Buried
C. Weatherproof and code-compliant
