Page 1 of 112
OSSF Installer I License Exam ACTUAL
QUESTIONS AND DETAILED SOLUTIONS
LATEST UPDATE THIS YEAR
OSSF Installer I License Exam — Summarized Coverage
The OSSF Installer I License Exam is administered through the Texas Commission on Environmental
Quality and evaluates competency in the installation, repair, maintenance, and regulatory compliance
of On-Site Sewage Facilities (OSSFs) such as septic systems. The exam emphasizes Texas OSSF rules,
site evaluation, safety, system components, and installation standards.
1. Texas OSSF laws, licensing requirements, and installer responsibilities
2. Texas Commission on Environmental Quality rules and regulatory authority over OSSFs
3. Types of onsite sewage systems and treatment methods
4. Conventional septic system components and operation principles
5. Aerobic treatment unit (ATU) systems and maintenance requirements
6. Soil science basics and soil texture classification
7. Site evaluation procedures and percolation testing concepts
8. Hydraulic loading and wastewater flow calculations
9. Septic tank sizing, placement, and construction requirements
10. Drainfield design and absorption area principles
11. Pipe installation standards, slope, and trench requirements
12. Distribution methods: gravity, pressure dosing, and low-pressure systems
13. Pump tanks, alarms, controls, and float switch operation
14. Effluent filters and wastewater treatment principles
15. Excavation safety and trenching requirements (OSHA basics)
16. Setback distances from wells, structures, and water sources
17. Surface water and groundwater protection requirements
18. Plumbing connections between structures and septic systems
19. Electrical basics related to aerobic systems and pumps
20. Installation sequencing and inspection procedures
21. Troubleshooting common OSSF failures and malfunctions
22. System maintenance requirements and service considerations
23. Repair permits and alteration procedures
24. Public health concerns associated with wastewater disposal
25. Environmental impact prevention and contamination control
26. Safety procedures when working around sewage and confined spaces
27. Reading site plans, permits, and installation drawings
28. Recordkeeping, documentation, and reporting requirements
29. Customer communication and regulatory compliance responsibilities
30. Scenario-based questions involving site suitability, installation errors, code violations,
troubleshooting, and system repair decisions
OSSF Installer I License Exam — Practice Questions (Batch 1: Questions 1–50)
, Page 2 of 112
Q1. Which Texas agency is primarily responsible for regulating and enforcing On-Site Sewage Facility
(OSSF) rules and licensing requirements?
A. Texas Department of Transportation
B. Texas Commission on Environmental Quality
C. Texas Railroad Commission
D. Texas Water Development Board
Answer: B
Rationale: The Texas Commission on Environmental Quality oversees OSSF regulation, licensing,
permitting, and enforcement activities statewide.
Q2. What is the primary purpose of a conventional septic tank in an onsite sewage system?
A. Disinfect wastewater completely before discharge
B. Separate solids from wastewater and begin treatment
C. Increase groundwater contamination rates
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D. Pump wastewater directly into public storm drains
Answer: B
Rationale: Septic tanks allow solids to settle while partially treating wastewater before drainfield
distribution.
Q3. Which soil texture generally absorbs wastewater the fastest during percolation testing procedures?
A. Clay soil
B. Silty clay
C. Sandy soil
D. Dense shale
Answer: C
Rationale: Sandy soils typically allow water to pass more rapidly because of larger pore spaces.
Q4. What is the main function of a drainfield in an onsite sewage facility system?
A. Store untreated sewage indefinitely
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B. Provide final wastewater dispersal and soil treatment
C. Increase sewage odors near buildings
D. Supply drinking water to structures
Answer: B
Rationale: Drainfields distribute effluent into soil for filtration and biological treatment.
Q5. Which safety practice is most important when entering a confined sewage-related space?
A. Enter quickly without ventilation
B. Ignore atmospheric testing requirements
C. Test atmosphere and follow confined space safety procedures
D. Work alone without communication equipment
Answer: C
Rationale: Sewage-related confined spaces may contain toxic gases and oxygen-deficient atmospheres.
OSSF Installer I License Exam ACTUAL
QUESTIONS AND DETAILED SOLUTIONS
LATEST UPDATE THIS YEAR
OSSF Installer I License Exam — Summarized Coverage
The OSSF Installer I License Exam is administered through the Texas Commission on Environmental
Quality and evaluates competency in the installation, repair, maintenance, and regulatory compliance
of On-Site Sewage Facilities (OSSFs) such as septic systems. The exam emphasizes Texas OSSF rules,
site evaluation, safety, system components, and installation standards.
1. Texas OSSF laws, licensing requirements, and installer responsibilities
2. Texas Commission on Environmental Quality rules and regulatory authority over OSSFs
3. Types of onsite sewage systems and treatment methods
4. Conventional septic system components and operation principles
5. Aerobic treatment unit (ATU) systems and maintenance requirements
6. Soil science basics and soil texture classification
7. Site evaluation procedures and percolation testing concepts
8. Hydraulic loading and wastewater flow calculations
9. Septic tank sizing, placement, and construction requirements
10. Drainfield design and absorption area principles
11. Pipe installation standards, slope, and trench requirements
12. Distribution methods: gravity, pressure dosing, and low-pressure systems
13. Pump tanks, alarms, controls, and float switch operation
14. Effluent filters and wastewater treatment principles
15. Excavation safety and trenching requirements (OSHA basics)
16. Setback distances from wells, structures, and water sources
17. Surface water and groundwater protection requirements
18. Plumbing connections between structures and septic systems
19. Electrical basics related to aerobic systems and pumps
20. Installation sequencing and inspection procedures
21. Troubleshooting common OSSF failures and malfunctions
22. System maintenance requirements and service considerations
23. Repair permits and alteration procedures
24. Public health concerns associated with wastewater disposal
25. Environmental impact prevention and contamination control
26. Safety procedures when working around sewage and confined spaces
27. Reading site plans, permits, and installation drawings
28. Recordkeeping, documentation, and reporting requirements
29. Customer communication and regulatory compliance responsibilities
30. Scenario-based questions involving site suitability, installation errors, code violations,
troubleshooting, and system repair decisions
OSSF Installer I License Exam — Practice Questions (Batch 1: Questions 1–50)
, Page 2 of 112
Q1. Which Texas agency is primarily responsible for regulating and enforcing On-Site Sewage Facility
(OSSF) rules and licensing requirements?
A. Texas Department of Transportation
B. Texas Commission on Environmental Quality
C. Texas Railroad Commission
D. Texas Water Development Board
Answer: B
Rationale: The Texas Commission on Environmental Quality oversees OSSF regulation, licensing,
permitting, and enforcement activities statewide.
Q2. What is the primary purpose of a conventional septic tank in an onsite sewage system?
A. Disinfect wastewater completely before discharge
B. Separate solids from wastewater and begin treatment
C. Increase groundwater contamination rates
, Page 3 of 112
D. Pump wastewater directly into public storm drains
Answer: B
Rationale: Septic tanks allow solids to settle while partially treating wastewater before drainfield
distribution.
Q3. Which soil texture generally absorbs wastewater the fastest during percolation testing procedures?
A. Clay soil
B. Silty clay
C. Sandy soil
D. Dense shale
Answer: C
Rationale: Sandy soils typically allow water to pass more rapidly because of larger pore spaces.
Q4. What is the main function of a drainfield in an onsite sewage facility system?
A. Store untreated sewage indefinitely
, Page 4 of 112
B. Provide final wastewater dispersal and soil treatment
C. Increase sewage odors near buildings
D. Supply drinking water to structures
Answer: B
Rationale: Drainfields distribute effluent into soil for filtration and biological treatment.
Q5. Which safety practice is most important when entering a confined sewage-related space?
A. Enter quickly without ventilation
B. Ignore atmospheric testing requirements
C. Test atmosphere and follow confined space safety procedures
D. Work alone without communication equipment
Answer: C
Rationale: Sewage-related confined spaces may contain toxic gases and oxygen-deficient atmospheres.
