Texas OSSF Installer II Study Guide
2026/2027 | Complete Exam Questions Bank
with Verified Answers & Detailed Rationales
| TCEQ 30 TAC 285 Certification Prep
TEXAS OSSF INSTALLER II — COMPLETE EXAM QUESTIONS BANK 2026/2027
TCEQ 30 TAC 285 Certification Prep | 200 Verified Questions with EXPERT
RATIONALE
• Study Guide Features: 200 exam-style multiple-choice questions with bolded
correct answers, detailed EXPERT RATIONALE, and full coverage of TCEQ 30 TAC
285 rules — including system design, setbacks, soil analysis, ATUs, permits, and
installation standards.
• How to Use This Material: Work through each question independently before
checking the correct answer and EXPERT RATIONALE; use the EXPERT RATIONALE
section to reinforce understanding of the why behind each rule, which is essential
for both the exam and real-world OSSF installation.
Q1. Under 30 TAC 285, what state agency has primary regulatory authority
over on-site sewage facilities (OSSFs) in Texas?
A. Texas Department of Health Services
B. Texas State Board of Plumbing Examiners
C. Texas Commission on Environmental Quality (TCEQ)
D. Texas Department of Licensing and Regulation
E. Texas Water Development Board
Correct Answer: C. Texas Commission on Environmental Quality (TCEQ)
EXPERT RATIONALE: TCEQ is designated as the primary regulatory authority over
OSSFs in Texas under 30 TAC Chapter 285, establishing rules for installation,
maintenance, and licensing of OSSF systems statewide.
,Q2. What does the acronym OSSF stand for?
A. Outdoor Sewage System Facility
B. On-Site Sewage Facility
C. On-Site Sanitation Foundation
D. Outdoor Sanitation and Septic Facility
E. On-Site Septic Flow
Correct Answer: B. On-Site Sewage Facility
EXPERT RATIONALE: OSSF is the official Texas regulatory term for any system that
treats and disposes of domestic sewage on the same property where the sewage is
generated, as defined in 30 TAC 285.
Q3. Which chapter of the Texas Administrative Code governs OSSFs?
A. Chapter 210
B. Chapter 217
C. Chapter 285
D. Chapter 290
E. Chapter 310
Correct Answer: C. Chapter 285
EXPERT RATIONALE: 30 TAC Chapter 285 is the specific chapter that regulates on-
site sewage facilities in Texas, covering permitting, design, installation, and
maintenance requirements.
Q4. An Installer II license in Texas authorizes the holder to do which of the
following?
,A. Design and install any OSSF system without restrictions
B. Install only conventional septic systems
C. Install all types of OSSF systems including aerobic treatment units
D. Perform site evaluations only
E. Inspect systems but not install them
Correct Answer: C. Install all types of OSSF systems including aerobic
treatment units
EXPERT RATIONALE: An Installer II license authorizes the holder to install all types
of OSSF systems, including aerobic treatment units (ATUs), whereas an Installer I is
limited to non-ATU conventional systems.
Q5. What is the minimum required setback distance from a water well to an
OSSF disposal area under 30 TAC 285?
A. 25 feet
B. 50 feet
C. 75 feet
D. 100 feet
E. 150 feet
Correct Answer: D. 100 feet
EXPERT RATIONALE: 30 TAC 285 requires a minimum setback of 100 feet between
a water well and an OSSF disposal area to protect groundwater from
contamination.
Q6. What is the minimum setback from a septic tank to a water well?
A. 25 feet
B. 50 feet
, C. 75 feet
D. 100 feet
E. 150 feet
Correct Answer: B. 50 feet
EXPERT RATIONALE: Under 30 TAC 285, the septic tank itself must be at least 50
feet from a water well, while the disposal (drainfield) area must be at least 100 feet
away.
Q7. What minimum setback is required between an OSSF disposal area and a
property line?
A. 5 feet
B. 10 feet
C. 15 feet
D. 25 feet
E. 50 feet
Correct Answer: B. 10 feet
EXPERT RATIONALE: 30 TAC 285 requires a minimum 10-foot setback between the
OSSF disposal area and any property line to protect neighboring properties.
Q8. The minimum setback distance from an OSSF disposal area to a surface
water body is:
A. 25 feet
B. 50 feet
C. 75 feet
D. 100 feet
2026/2027 | Complete Exam Questions Bank
with Verified Answers & Detailed Rationales
| TCEQ 30 TAC 285 Certification Prep
TEXAS OSSF INSTALLER II — COMPLETE EXAM QUESTIONS BANK 2026/2027
TCEQ 30 TAC 285 Certification Prep | 200 Verified Questions with EXPERT
RATIONALE
• Study Guide Features: 200 exam-style multiple-choice questions with bolded
correct answers, detailed EXPERT RATIONALE, and full coverage of TCEQ 30 TAC
285 rules — including system design, setbacks, soil analysis, ATUs, permits, and
installation standards.
• How to Use This Material: Work through each question independently before
checking the correct answer and EXPERT RATIONALE; use the EXPERT RATIONALE
section to reinforce understanding of the why behind each rule, which is essential
for both the exam and real-world OSSF installation.
Q1. Under 30 TAC 285, what state agency has primary regulatory authority
over on-site sewage facilities (OSSFs) in Texas?
A. Texas Department of Health Services
B. Texas State Board of Plumbing Examiners
C. Texas Commission on Environmental Quality (TCEQ)
D. Texas Department of Licensing and Regulation
E. Texas Water Development Board
Correct Answer: C. Texas Commission on Environmental Quality (TCEQ)
EXPERT RATIONALE: TCEQ is designated as the primary regulatory authority over
OSSFs in Texas under 30 TAC Chapter 285, establishing rules for installation,
maintenance, and licensing of OSSF systems statewide.
,Q2. What does the acronym OSSF stand for?
A. Outdoor Sewage System Facility
B. On-Site Sewage Facility
C. On-Site Sanitation Foundation
D. Outdoor Sanitation and Septic Facility
E. On-Site Septic Flow
Correct Answer: B. On-Site Sewage Facility
EXPERT RATIONALE: OSSF is the official Texas regulatory term for any system that
treats and disposes of domestic sewage on the same property where the sewage is
generated, as defined in 30 TAC 285.
Q3. Which chapter of the Texas Administrative Code governs OSSFs?
A. Chapter 210
B. Chapter 217
C. Chapter 285
D. Chapter 290
E. Chapter 310
Correct Answer: C. Chapter 285
EXPERT RATIONALE: 30 TAC Chapter 285 is the specific chapter that regulates on-
site sewage facilities in Texas, covering permitting, design, installation, and
maintenance requirements.
Q4. An Installer II license in Texas authorizes the holder to do which of the
following?
,A. Design and install any OSSF system without restrictions
B. Install only conventional septic systems
C. Install all types of OSSF systems including aerobic treatment units
D. Perform site evaluations only
E. Inspect systems but not install them
Correct Answer: C. Install all types of OSSF systems including aerobic
treatment units
EXPERT RATIONALE: An Installer II license authorizes the holder to install all types
of OSSF systems, including aerobic treatment units (ATUs), whereas an Installer I is
limited to non-ATU conventional systems.
Q5. What is the minimum required setback distance from a water well to an
OSSF disposal area under 30 TAC 285?
A. 25 feet
B. 50 feet
C. 75 feet
D. 100 feet
E. 150 feet
Correct Answer: D. 100 feet
EXPERT RATIONALE: 30 TAC 285 requires a minimum setback of 100 feet between
a water well and an OSSF disposal area to protect groundwater from
contamination.
Q6. What is the minimum setback from a septic tank to a water well?
A. 25 feet
B. 50 feet
, C. 75 feet
D. 100 feet
E. 150 feet
Correct Answer: B. 50 feet
EXPERT RATIONALE: Under 30 TAC 285, the septic tank itself must be at least 50
feet from a water well, while the disposal (drainfield) area must be at least 100 feet
away.
Q7. What minimum setback is required between an OSSF disposal area and a
property line?
A. 5 feet
B. 10 feet
C. 15 feet
D. 25 feet
E. 50 feet
Correct Answer: B. 10 feet
EXPERT RATIONALE: 30 TAC 285 requires a minimum 10-foot setback between the
OSSF disposal area and any property line to protect neighboring properties.
Q8. The minimum setback distance from an OSSF disposal area to a surface
water body is:
A. 25 feet
B. 50 feet
C. 75 feet
D. 100 feet
