Page 1 of 26
OSSF DR PRACTICE EXAM NEWEST 2026
ACTUAL EXAM QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) ALL
ANSWERED {150 Q & A} ALREADY GRADED A+ |
BRAND NEW! | 100% GUARANTEED PASS
An LPD system for a new three-bedroom home with 2200 Sq ft
(having water-saving devices) with 9-inch-wide trenches with 1
foot of gravel depth installed in Class III soil would require
__________ linear feet of dosing pipe. - ✔✔✔ Correct Answer > 400
What is the purpose of the inlet baffle or T? - ✔✔✔ Correct Answer >
Reduce velocity and disperse flow, vent the tank to the building
plumbing
The minimum distances a watertight sewage treatment tank
should be from a water-well and a property line are - ✔✔✔ Correct
Answer > 50 feet and 5 feet respectively
Which of the following is true regarding septic tanks? - ✔✔✔ Correct
Answer > The must have two- or three-compartments
,Page 2 of 26
A septic tank serving a new five-bedroom home with 3800 sqft
must have a minimum capacity of - ✔✔✔ Correct Answer > 1,250
gallons
Of what materials may a septic tank be constructed? - ✔✔✔ Correct
Answer > steel reinforced concrete
The expected volume of wastewater (Q) in gal/day from an older
(pre-1990) three-bedroom mobile home would be - ✔✔✔ Correct
Answer > 300
Which of the following characteristics should a poured-in-place
concrete septic tanks have? - ✔✔✔ Correct Answer > watertight,
designed by PE, Structurally sound
The standard inlet and outlet devices in a septic tank should be -
✔✔✔ Correct Answer > tees
Properly sealed septic tanks are - ✔✔✔ Correct Answer > vented
through the building plumbing
The liquid depth of a septic tank - ✔✔✔ Correct Answer > must be at
least 30 inches
, Page 3 of 26
Which of the following is true of a septic tank with 15 inches of
cover? - ✔✔✔ Correct Answer > it must have an access port with a
riser
Which if the following is acceptable for the line from the building
to the treatment tank? - ✔✔✔ Correct Answer > cast iron, SDR 26
plastic pipe, and Schedule 40 plastic pipe
Most of the settable solids and scum that enter a properly
designed septic tank will be - ✔✔✔ Correct Answer > removed in the
first compartment
Which of the following should a house sewer have? - ✔✔✔ Correct
Answer > 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? - ✔✔✔
Correct Answer > 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 - ✔✔✔ Correct Answer > F
OSSF DR PRACTICE EXAM NEWEST 2026
ACTUAL EXAM QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) ALL
ANSWERED {150 Q & A} ALREADY GRADED A+ |
BRAND NEW! | 100% GUARANTEED PASS
An LPD system for a new three-bedroom home with 2200 Sq ft
(having water-saving devices) with 9-inch-wide trenches with 1
foot of gravel depth installed in Class III soil would require
__________ linear feet of dosing pipe. - ✔✔✔ Correct Answer > 400
What is the purpose of the inlet baffle or T? - ✔✔✔ Correct Answer >
Reduce velocity and disperse flow, vent the tank to the building
plumbing
The minimum distances a watertight sewage treatment tank
should be from a water-well and a property line are - ✔✔✔ Correct
Answer > 50 feet and 5 feet respectively
Which of the following is true regarding septic tanks? - ✔✔✔ Correct
Answer > The must have two- or three-compartments
,Page 2 of 26
A septic tank serving a new five-bedroom home with 3800 sqft
must have a minimum capacity of - ✔✔✔ Correct Answer > 1,250
gallons
Of what materials may a septic tank be constructed? - ✔✔✔ Correct
Answer > steel reinforced concrete
The expected volume of wastewater (Q) in gal/day from an older
(pre-1990) three-bedroom mobile home would be - ✔✔✔ Correct
Answer > 300
Which of the following characteristics should a poured-in-place
concrete septic tanks have? - ✔✔✔ Correct Answer > watertight,
designed by PE, Structurally sound
The standard inlet and outlet devices in a septic tank should be -
✔✔✔ Correct Answer > tees
Properly sealed septic tanks are - ✔✔✔ Correct Answer > vented
through the building plumbing
The liquid depth of a septic tank - ✔✔✔ Correct Answer > must be at
least 30 inches
, Page 3 of 26
Which of the following is true of a septic tank with 15 inches of
cover? - ✔✔✔ Correct Answer > it must have an access port with a
riser
Which if the following is acceptable for the line from the building
to the treatment tank? - ✔✔✔ Correct Answer > cast iron, SDR 26
plastic pipe, and Schedule 40 plastic pipe
Most of the settable solids and scum that enter a properly
designed septic tank will be - ✔✔✔ Correct Answer > removed in the
first compartment
Which of the following should a house sewer have? - ✔✔✔ Correct
Answer > 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? - ✔✔✔
Correct Answer > 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 - ✔✔✔ Correct Answer > F
