OSSF DR FINAL EXAM 2026/2027 WITH
ACTUAL CORRECT QUESTIONS AND
VERIFIED DETAILED ANSWERS
|CURRENTLY TESTING QUESTIONS AND
SOLUTIONS|ALREADY GRADED A+|NEWEST
|BRAND NEW VERSION|JUST RELEASED!!
Which of the following should a house sewer have?
A two way sanitary clean-out, minimum 1/8 inch per foot fall, minimum diameter of 3 inches
Which of the following applies if effluent is to be pumped?
A high-water alarm must be provided, the pump must be installed in a separate chamber, a
check valve should be in line if the disposal area is upgrade
T/F: Septic tanks may be 1.5 inch-thick steel
F
T/F: Septic tanks may be reinforced fiberglass
T
T/F: Two single-compartment septic tanks in series are allowed
T
How many spray heads would be needed for an older four bedroom home without water-saving
devices in Beaumont, Texas (note: extreme southeast Texas) to meet minimum requirements for
spray are is rotary heads sent out a spray 30 feet?
4
1|Page
,T/F: A two-compartment septic tank is allowed
T
T/F: One single-compartment septic tank that is sized properly is allowed.
F
T/F: Tees are allowed for inlet and outlet devices
T
T/F: An inlet line should be at least 3 inches above the liquid level.
T
T/F: A leakage from the tank or joints of 1.6 gallons/hour is permissible
F
T/F: A 12-inch port (minimum) must be provided in the top of the tank
T
T/F: The first compartment should be smaller than the second compartment
F....Should be 1/2 to 2/3s the second
T/F: Outlet Tee should extend to the bottom of the tank
F
T/F: The tank must be level
T
T/F: A minimum 4-inch-thick sand, sandy loam, clay loam, or pea gravel pad is required under
prefabricated tanks
T
The standard drainfield depth in East and Central Texas is limited to
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, 18 inches minimum and 36 inches maximum
The minimum distance between standard drainfield excavations is
3 feet
Grease interceptors are needed
on wastewater lines from commercial kitchens
Which of the following is true if porous media in a standard drainfield?
It should be uniform in size, it should be 0.75 inch to 2 inches in size, it should be clean and
resistant to breakdown
A standard drainfield excavation should
be level within 1 inch per 25 feet or a maximum of 3 inches whichever is less
A standard perforated drainline should be which of the following?
3 inches to 4 inches in diameter, a maximum length of 150 feet, laid parallel in multiple-line
system
The purpose of the geotextile fabric over gravel is to
prevent backfill from entering porous media
A pumped effluent drainfield
is an alternative for well-drained clay soils on nearly level sites, has a 2% or less slope for single-
family dwellings only
Which of the following must be known prior to actually laying out a new OSSF?
building location, size of the property, soil conditions in the drainfield
In an unlined ET system, wastewater is disposed of by which of the following?
evaporation, transpiration, soil absorption
3|Page
ACTUAL CORRECT QUESTIONS AND
VERIFIED DETAILED ANSWERS
|CURRENTLY TESTING QUESTIONS AND
SOLUTIONS|ALREADY GRADED A+|NEWEST
|BRAND NEW VERSION|JUST RELEASED!!
Which of the following should a house sewer have?
A two way sanitary clean-out, minimum 1/8 inch per foot fall, minimum diameter of 3 inches
Which of the following applies if effluent is to be pumped?
A high-water alarm must be provided, the pump must be installed in a separate chamber, a
check valve should be in line if the disposal area is upgrade
T/F: Septic tanks may be 1.5 inch-thick steel
F
T/F: Septic tanks may be reinforced fiberglass
T
T/F: Two single-compartment septic tanks in series are allowed
T
How many spray heads would be needed for an older four bedroom home without water-saving
devices in Beaumont, Texas (note: extreme southeast Texas) to meet minimum requirements for
spray are is rotary heads sent out a spray 30 feet?
4
1|Page
,T/F: A two-compartment septic tank is allowed
T
T/F: One single-compartment septic tank that is sized properly is allowed.
F
T/F: Tees are allowed for inlet and outlet devices
T
T/F: An inlet line should be at least 3 inches above the liquid level.
T
T/F: A leakage from the tank or joints of 1.6 gallons/hour is permissible
F
T/F: A 12-inch port (minimum) must be provided in the top of the tank
T
T/F: The first compartment should be smaller than the second compartment
F....Should be 1/2 to 2/3s the second
T/F: Outlet Tee should extend to the bottom of the tank
F
T/F: The tank must be level
T
T/F: A minimum 4-inch-thick sand, sandy loam, clay loam, or pea gravel pad is required under
prefabricated tanks
T
The standard drainfield depth in East and Central Texas is limited to
2|Page
, 18 inches minimum and 36 inches maximum
The minimum distance between standard drainfield excavations is
3 feet
Grease interceptors are needed
on wastewater lines from commercial kitchens
Which of the following is true if porous media in a standard drainfield?
It should be uniform in size, it should be 0.75 inch to 2 inches in size, it should be clean and
resistant to breakdown
A standard drainfield excavation should
be level within 1 inch per 25 feet or a maximum of 3 inches whichever is less
A standard perforated drainline should be which of the following?
3 inches to 4 inches in diameter, a maximum length of 150 feet, laid parallel in multiple-line
system
The purpose of the geotextile fabric over gravel is to
prevent backfill from entering porous media
A pumped effluent drainfield
is an alternative for well-drained clay soils on nearly level sites, has a 2% or less slope for single-
family dwellings only
Which of the following must be known prior to actually laying out a new OSSF?
building location, size of the property, soil conditions in the drainfield
In an unlined ET system, wastewater is disposed of by which of the following?
evaporation, transpiration, soil absorption
3|Page
