OSSF TEST PRACTICE EXAM 2026
PRACTICE QUESTIONS AND CORRECT
ANSWERS FULL PREPARATION RESOURCE
ACCURATE CONTENT GRADED A+
⩥ Class III.
Answer: Silt, Silt loam, Silty Clay Loam, Clay Loam, Sandy Clay Loam,
Sandy Clay
⩥ Water conservation measures fall under these 3 categories.
Answer: Maintenance of plumbing system, low flow fixtures, lifestyle
changes
⩥ The value Q is.
Answer: Quantity of sewage (g/day)
⩥ Primary considerations for OSSF selection.
Answer: soil conditions and soil classifcation
⩥ Secondary considerations for OSSF selection.
Answer: cost, maintenance, simplicity, reliability
,⩥ Sewer stub outs can be constructed of.
Answer: cast iron, ductile iron, PVC Schedule 40, SDR 26, must be at
highest possible elevation with respect to foundation
⩥ Sewer pipe below a driveway must.
Answer: be schedule 80 or sleeved in schedule 40
⩥ Pipe from house to unit must be.
Answer: at least as large as stub and no less than 3"
slope must have 1/8" fall per foot
⩥ Between the building and septic tank, this must be provided.
Answer: 2 way cleanout
⩥ Additional cleanouts (may be single type) must be provided.
Answer: every 100' and within 5' upstream of every 90
⩥ The first compartment in a 2 compartment septic tank must.
Answer: contain 1/2 to 2/3 of the required volume
⩥ The first compartment in a 3 compartment septic tank must.
Answer: contain 1/3 required volume but not less than 500g
, ⩥ Acceptable materials for septic tank construction.
Answer: steel-reinforced concrete, fiberglass, reinforced plastic
polyethylene
⩥ Poured in place concrete tanks must be.
Answer: designed by PE w/ relevant experience
⩥ Inflow line must be how many inches above tank operating level?.
Answer: 3"
⩥ Entry points for final outlet device and outlets between compartments
should be.
Answer: 25-50% below the surface
⩥ How large must the port over a tank be?.
Answer: 12"
⩥ Risers must come within how many inches of the surface (on septic).
Answer: 6"
⩥ The liquid depth of the tank shall be at least.
PRACTICE QUESTIONS AND CORRECT
ANSWERS FULL PREPARATION RESOURCE
ACCURATE CONTENT GRADED A+
⩥ Class III.
Answer: Silt, Silt loam, Silty Clay Loam, Clay Loam, Sandy Clay Loam,
Sandy Clay
⩥ Water conservation measures fall under these 3 categories.
Answer: Maintenance of plumbing system, low flow fixtures, lifestyle
changes
⩥ The value Q is.
Answer: Quantity of sewage (g/day)
⩥ Primary considerations for OSSF selection.
Answer: soil conditions and soil classifcation
⩥ Secondary considerations for OSSF selection.
Answer: cost, maintenance, simplicity, reliability
,⩥ Sewer stub outs can be constructed of.
Answer: cast iron, ductile iron, PVC Schedule 40, SDR 26, must be at
highest possible elevation with respect to foundation
⩥ Sewer pipe below a driveway must.
Answer: be schedule 80 or sleeved in schedule 40
⩥ Pipe from house to unit must be.
Answer: at least as large as stub and no less than 3"
slope must have 1/8" fall per foot
⩥ Between the building and septic tank, this must be provided.
Answer: 2 way cleanout
⩥ Additional cleanouts (may be single type) must be provided.
Answer: every 100' and within 5' upstream of every 90
⩥ The first compartment in a 2 compartment septic tank must.
Answer: contain 1/2 to 2/3 of the required volume
⩥ The first compartment in a 3 compartment septic tank must.
Answer: contain 1/3 required volume but not less than 500g
, ⩥ Acceptable materials for septic tank construction.
Answer: steel-reinforced concrete, fiberglass, reinforced plastic
polyethylene
⩥ Poured in place concrete tanks must be.
Answer: designed by PE w/ relevant experience
⩥ Inflow line must be how many inches above tank operating level?.
Answer: 3"
⩥ Entry points for final outlet device and outlets between compartments
should be.
Answer: 25-50% below the surface
⩥ How large must the port over a tank be?.
Answer: 12"
⩥ Risers must come within how many inches of the surface (on septic).
Answer: 6"
⩥ The liquid depth of the tank shall be at least.
