Arkansas Onsite Wastewater Designer Exam
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A.
1. What agency regulates onsite wastewater systems in Arkansas?
A. Arkansas Department of Environmental Quality
B. Arkansas Department of Health
C. Environmental Protection Agency
D. County Health Office
Answer: B
The Arkansas Department of Health (ADH) has regulatory
authority over onsite wastewater systems.
2. The primary purpose of an onsite wastewater system is to:
A. Recycle wastewater
B. Discharge wastewater to surface water
C. Treat and disperse wastewater safely
D. Store wastewater permanently
Answer: C
Onsite systems are designed to treat wastewater and disperse it
into the soil without harming public health.
3. Which soil characteristic most influences absorption trench
performance?
A. Color
B. Texture
C. Smell
D. Temperature
Answer: B
Soil texture affects permeability and wastewater movement.
,4. A percolation test measures:
A. Soil fertility
B. Soil compaction
C. Soil absorption rate
D. Groundwater depth
Answer: C
Percolation tests determine how quickly soil absorbs water.
5. Minimum vertical separation between the absorption trench bottom
and seasonal water table is typically:
A. 6 inches
B. 12 inches
C. 24 inches
D. 36 inches
Answer: C
Arkansas regulations generally require at least 24 inches of
separation.
6. Which component receives wastewater directly from the building
sewer?
A. Distribution box
B. Absorption trench
C. Septic tank
D. Soil
Answer: C
The septic tank is the first treatment component.
7. The main function of a septic tank is to:
A. Kill bacteria
B. Disinfect wastewater
C. Separate solids from liquids
D. Absorb wastewater
Answer: C
Septic tanks allow solids to settle and scum to float.
8. Effluent leaving the septic tank flows next to the:
A. Cleanout
B. Absorption field
C. Building sewer
, D. Water supply
Answer: B
Effluent is distributed to the absorption field for final treatment.
9. What material is commonly used for septic tanks?
A. Wood
B. Plastic, fiberglass, or concrete
C. Steel only
D. Clay
Answer: B
Approved septic tanks are made of durable, watertight materials.
10. A distribution box is used to:
A. Store sludge
B. Equalize flow to trenches
C. Filter solids
D. Measure flow rate
Answer: B
Distribution boxes evenly distribute effluent.
11. Which factor determines the required size of an absorption
field?
A. House color
B. Number of bedrooms
C. Roof area
D. Lot size
Answer: B
System sizing is based on estimated daily wastewater flow.
12. One bedroom is typically assumed to generate how many
gallons per day?
A. 75
B. 100
C. 150
D. 300
Answer: C
Arkansas design standards commonly use 150 gallons per
bedroom.
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A.
1. What agency regulates onsite wastewater systems in Arkansas?
A. Arkansas Department of Environmental Quality
B. Arkansas Department of Health
C. Environmental Protection Agency
D. County Health Office
Answer: B
The Arkansas Department of Health (ADH) has regulatory
authority over onsite wastewater systems.
2. The primary purpose of an onsite wastewater system is to:
A. Recycle wastewater
B. Discharge wastewater to surface water
C. Treat and disperse wastewater safely
D. Store wastewater permanently
Answer: C
Onsite systems are designed to treat wastewater and disperse it
into the soil without harming public health.
3. Which soil characteristic most influences absorption trench
performance?
A. Color
B. Texture
C. Smell
D. Temperature
Answer: B
Soil texture affects permeability and wastewater movement.
,4. A percolation test measures:
A. Soil fertility
B. Soil compaction
C. Soil absorption rate
D. Groundwater depth
Answer: C
Percolation tests determine how quickly soil absorbs water.
5. Minimum vertical separation between the absorption trench bottom
and seasonal water table is typically:
A. 6 inches
B. 12 inches
C. 24 inches
D. 36 inches
Answer: C
Arkansas regulations generally require at least 24 inches of
separation.
6. Which component receives wastewater directly from the building
sewer?
A. Distribution box
B. Absorption trench
C. Septic tank
D. Soil
Answer: C
The septic tank is the first treatment component.
7. The main function of a septic tank is to:
A. Kill bacteria
B. Disinfect wastewater
C. Separate solids from liquids
D. Absorb wastewater
Answer: C
Septic tanks allow solids to settle and scum to float.
8. Effluent leaving the septic tank flows next to the:
A. Cleanout
B. Absorption field
C. Building sewer
, D. Water supply
Answer: B
Effluent is distributed to the absorption field for final treatment.
9. What material is commonly used for septic tanks?
A. Wood
B. Plastic, fiberglass, or concrete
C. Steel only
D. Clay
Answer: B
Approved septic tanks are made of durable, watertight materials.
10. A distribution box is used to:
A. Store sludge
B. Equalize flow to trenches
C. Filter solids
D. Measure flow rate
Answer: B
Distribution boxes evenly distribute effluent.
11. Which factor determines the required size of an absorption
field?
A. House color
B. Number of bedrooms
C. Roof area
D. Lot size
Answer: B
System sizing is based on estimated daily wastewater flow.
12. One bedroom is typically assumed to generate how many
gallons per day?
A. 75
B. 100
C. 150
D. 300
Answer: C
Arkansas design standards commonly use 150 gallons per
bedroom.
