OSSF INSTALLER I LICENSE EXAM PREP (2026)
QUESTION 1
What is the primary purpose of an On-Site Sewage Facility (OSSF)?
A. To supply drinking water
B. To treat and dispose of wastewater on-site
C. To store rainwater
D. To irrigate crops only
Correct Answer: B
Rationale:
OSSFs are designed specifically to treat and dispose of domestic wastewater safely at the location where
it is generated.
QUESTION 2
Which soil type is MOST suitable for a standard absorption drain field?
A. Clay
B. Sand
C. Rock
D. Silt
Correct Answer: B
Rationale:
Sandy soils allow better percolation and filtration, making them ideal for drain fields compared to clay,
which drains poorly.
QUESTION 3
What is the minimum separation distance between an OSSF and a private water well (typical standard)?
A. 10 feet
B. 25 feet
, C. 50 feet
D. 100 feet
Correct Answer: D
Rationale:
A 100-foot separation helps prevent contamination of drinking water sources.
QUESTION 4
Which component separates solids from wastewater in a septic system?
A. Pump tank
B. Distribution box
C. Septic tank
D. Spray head
Correct Answer: C
Rationale:
The septic tank allows solids to settle (sludge) and float (scum), separating them from effluent.
QUESTION 5
What is “effluent”?
A. Untreated sewage
B. Treated wastewater leaving the system
C. Rainwater runoff
D. Groundwater
Correct Answer: B
Rationale:
Effluent is the partially treated liquid that exits the septic tank and flows to further treatment/disposal.
QUESTION 6
Which system uses oxygen to treat wastewater?
QUESTION 1
What is the primary purpose of an On-Site Sewage Facility (OSSF)?
A. To supply drinking water
B. To treat and dispose of wastewater on-site
C. To store rainwater
D. To irrigate crops only
Correct Answer: B
Rationale:
OSSFs are designed specifically to treat and dispose of domestic wastewater safely at the location where
it is generated.
QUESTION 2
Which soil type is MOST suitable for a standard absorption drain field?
A. Clay
B. Sand
C. Rock
D. Silt
Correct Answer: B
Rationale:
Sandy soils allow better percolation and filtration, making them ideal for drain fields compared to clay,
which drains poorly.
QUESTION 3
What is the minimum separation distance between an OSSF and a private water well (typical standard)?
A. 10 feet
B. 25 feet
, C. 50 feet
D. 100 feet
Correct Answer: D
Rationale:
A 100-foot separation helps prevent contamination of drinking water sources.
QUESTION 4
Which component separates solids from wastewater in a septic system?
A. Pump tank
B. Distribution box
C. Septic tank
D. Spray head
Correct Answer: C
Rationale:
The septic tank allows solids to settle (sludge) and float (scum), separating them from effluent.
QUESTION 5
What is “effluent”?
A. Untreated sewage
B. Treated wastewater leaving the system
C. Rainwater runoff
D. Groundwater
Correct Answer: B
Rationale:
Effluent is the partially treated liquid that exits the septic tank and flows to further treatment/disposal.
QUESTION 6
Which system uses oxygen to treat wastewater?
