TCEQ DESIGNATED REPRESENTATIVE OSSF PRACTICE EXAM:
COMPLETE COVERAGE OF INSTALLER II, SITE EVALUATOR, SOIL
MECHANICS, SETBACK REGULATIONS, AND LICENSING
REQUIREMENTS (2026/2027 EDITION)
1. How many hours of TCEQ approved continuing education are
required annually to maintain an OSSF license?
24 hours
2. Which Texas agency adopted the current OSSF Rules in 1997?
TCEQ
3. Who is responsible for reviewing permit applications and
conducting inspections of OSSFs?
Designated Representative
4. Which specific OSSF license category requires proof of previous
experience before obtaining it?
Installer II & Maintenance Provider
5. Which individual is responsible for conducting soil evaluations and a
site survey?
Site Evaluator
6. Who is defined as an individual who holds a valid license and is
compensated by another to install or repair an OSSF?
Installer
,7. What is the minimum horizontal setback distance required from an
OSSF to a private water well?
50 feet
8. What is the minimum horizontal setback distance required from an
OSSF to a public water supply well?
100 feet
9. What is the required minimum horizontal setback distance between
an OSSF and a building foundation?
5 feet
10. What is the minimum required setback distance from an OSSF to
an adjacent property line?
5 feet
11. What is the minimum setback distance for an OSSF from a
drainage ditch or canal?
10 feet
12. What is the minimum horizontal setback distance from an OSSF to
a swimming pool?
5 feet
13. What is the minimum horizontal separation distance required
between an OSSF and a water supply line?
10 feet
14. What is the minimum vertical separation distance required from
the bottom of an OSSF trench to the seasonal high water table?
2 feet
,15. What is the minimum vertical separation distance required from
the bottom of an OSSF trench to solid bedrock?
2 feet
16. Which soil texture class is considered the primary limiting factor
for conventional OSSF installation due to slow permeability?
Clay
17. What is the minimum percolation rate (in minutes per inch)
generally required for a conventional OSSF absorption field?
Not less than 1 minute per inch (or 60 min/inch depending on specific
rule, typically 1-60)
18. What is the maximum percolation rate (in minutes per inch)
allowed for a conventional OSSF absorption field?
60 minutes per inch
19. What does OSSF stand for?
On-Site Sewage Facility
20. What type of OSSF is typically used for sites with high water tables
or shallow soils?
Mound system
21. Which OSSF component is responsible for primary treatment and
separation of solids from liquids?
Septic tank
22. What is the minimum recommended capacity (in gallons) of a
septic tank for a single-family residence?
1,000 gallons
, 23. How often should a septic tank be pumped out for normal
household use?
Every 3 to 5 years
24. What is the primary purpose of a distribution box in an OSSF?
To evenly distribute effluent to the absorption field lines
25. What does the term "effluent" refer to in OSSF terminology?
The liquid discharged from the septic tank
26. What does the term "scum" refer to in a septic tank?
Materials that float to the top of the tank
27. Which chemical agent is prohibited from being introduced into a
septic system?
Chlorine bleach / harmful chemical additives
28. What is the purpose of an effluent filter installed on a septic tank
outlet?
To prevent solids from exiting the tank and clogging the drain field
29. Which type of OSSF is designed to use the soil as a filter for
treating effluent?
Conventional subsurface absorption field
30. What is the maximum allowable slope for a conventional drain
field installation?
20% (or specific slope limits as per local TCEQ rules, typically max 20%)
31. What is the required maximum depth of a conventional drain field
trench?
36 inches (or up to 4 feet depending on specific local restrictions)
COMPLETE COVERAGE OF INSTALLER II, SITE EVALUATOR, SOIL
MECHANICS, SETBACK REGULATIONS, AND LICENSING
REQUIREMENTS (2026/2027 EDITION)
1. How many hours of TCEQ approved continuing education are
required annually to maintain an OSSF license?
24 hours
2. Which Texas agency adopted the current OSSF Rules in 1997?
TCEQ
3. Who is responsible for reviewing permit applications and
conducting inspections of OSSFs?
Designated Representative
4. Which specific OSSF license category requires proof of previous
experience before obtaining it?
Installer II & Maintenance Provider
5. Which individual is responsible for conducting soil evaluations and a
site survey?
Site Evaluator
6. Who is defined as an individual who holds a valid license and is
compensated by another to install or repair an OSSF?
Installer
,7. What is the minimum horizontal setback distance required from an
OSSF to a private water well?
50 feet
8. What is the minimum horizontal setback distance required from an
OSSF to a public water supply well?
100 feet
9. What is the required minimum horizontal setback distance between
an OSSF and a building foundation?
5 feet
10. What is the minimum required setback distance from an OSSF to
an adjacent property line?
5 feet
11. What is the minimum setback distance for an OSSF from a
drainage ditch or canal?
10 feet
12. What is the minimum horizontal setback distance from an OSSF to
a swimming pool?
5 feet
13. What is the minimum horizontal separation distance required
between an OSSF and a water supply line?
10 feet
14. What is the minimum vertical separation distance required from
the bottom of an OSSF trench to the seasonal high water table?
2 feet
,15. What is the minimum vertical separation distance required from
the bottom of an OSSF trench to solid bedrock?
2 feet
16. Which soil texture class is considered the primary limiting factor
for conventional OSSF installation due to slow permeability?
Clay
17. What is the minimum percolation rate (in minutes per inch)
generally required for a conventional OSSF absorption field?
Not less than 1 minute per inch (or 60 min/inch depending on specific
rule, typically 1-60)
18. What is the maximum percolation rate (in minutes per inch)
allowed for a conventional OSSF absorption field?
60 minutes per inch
19. What does OSSF stand for?
On-Site Sewage Facility
20. What type of OSSF is typically used for sites with high water tables
or shallow soils?
Mound system
21. Which OSSF component is responsible for primary treatment and
separation of solids from liquids?
Septic tank
22. What is the minimum recommended capacity (in gallons) of a
septic tank for a single-family residence?
1,000 gallons
, 23. How often should a septic tank be pumped out for normal
household use?
Every 3 to 5 years
24. What is the primary purpose of a distribution box in an OSSF?
To evenly distribute effluent to the absorption field lines
25. What does the term "effluent" refer to in OSSF terminology?
The liquid discharged from the septic tank
26. What does the term "scum" refer to in a septic tank?
Materials that float to the top of the tank
27. Which chemical agent is prohibited from being introduced into a
septic system?
Chlorine bleach / harmful chemical additives
28. What is the purpose of an effluent filter installed on a septic tank
outlet?
To prevent solids from exiting the tank and clogging the drain field
29. Which type of OSSF is designed to use the soil as a filter for
treating effluent?
Conventional subsurface absorption field
30. What is the maximum allowable slope for a conventional drain
field installation?
20% (or specific slope limits as per local TCEQ rules, typically max 20%)
31. What is the required maximum depth of a conventional drain field
trench?
36 inches (or up to 4 feet depending on specific local restrictions)
