Arizona Certified Septic System Installer Exam – Practice Test
(Questions 1–100)
Format:
• Correct answers bold
• Rationales italicized
1. What is the primary purpose of a septic tank in an onsite
wastewater system?
A. Remove all pathogens
B. Aerate wastewater
C. Separate solids from wastewater
D. Evaporate wastewater
The septic tank’s main function is sedimentation—solids settle and float
while clarified effluent exits.
2. Which Arizona agency oversees onsite wastewater treatment
system regulations?
A. Arizona State Land Department
B. Arizona Department of Transportation
C. Arizona Department of Environmental Quality (ADEQ)
D. U.S. Geological Survey
ADEQ regulates onsite wastewater treatment systems under Arizona
Administrative Code.
3. Which soil characteristic most affects effluent infiltration rates?
,A. Soil color
B. Soil texture
C. Soil odor
D. Soil temperature
Texture determines permeability and suitability for dispersal.
4. What does percolation testing primarily measure?
A. Soil acidity
B. Water absorption rate
C. Soil nitrogen levels
D. Organic matter percentage
Percolation tests determine how quickly water infiltrates the soil.
5. What is the minimum setback from a potable water well for a
conventional septic system in Arizona?
A. 25 feet
B. 50 feet
C. 100 feet
D. 500 feet
Arizona regulations require at least 100 feet of separation.
6. What is the purpose of an effluent filter?
A. Reduce odors
B. Prevent solids from exiting the tank
C. Increase aeration
D. Remove pathogens
Effluent filters trap fine solids before they reach the dispersal system.
7. Which component distributes effluent evenly in a gravity system?
, A. Chlorination unit
B. Surge tank
C. Distribution box
D. Transfer pump
Distribution boxes split flow evenly across trenches.
8. What type of soil is generally unsuitable for a leach field?
A. Loamy sand
B. Clay
C. Sandy loam
D. Gravel
Clay soils have very low permeability and fail to absorb effluent
sufficiently.
9. What is the typical minimum septic tank capacity for a three-
bedroom home in Arizona?
A. 500 gallons
B. 750 gallons
C. 1,000 gallons
D. 1,250 gallons
Standard sizing guidelines recommend at least 1,000 gallons.
10. What is the main purpose of the leach field?
A. Remove solids
B. Aerate wastewater
C. Disperse effluent into the soil
D. Grind organic matter
The dispersal field allows effluent to filter naturally through soil.
(Questions 1–100)
Format:
• Correct answers bold
• Rationales italicized
1. What is the primary purpose of a septic tank in an onsite
wastewater system?
A. Remove all pathogens
B. Aerate wastewater
C. Separate solids from wastewater
D. Evaporate wastewater
The septic tank’s main function is sedimentation—solids settle and float
while clarified effluent exits.
2. Which Arizona agency oversees onsite wastewater treatment
system regulations?
A. Arizona State Land Department
B. Arizona Department of Transportation
C. Arizona Department of Environmental Quality (ADEQ)
D. U.S. Geological Survey
ADEQ regulates onsite wastewater treatment systems under Arizona
Administrative Code.
3. Which soil characteristic most affects effluent infiltration rates?
,A. Soil color
B. Soil texture
C. Soil odor
D. Soil temperature
Texture determines permeability and suitability for dispersal.
4. What does percolation testing primarily measure?
A. Soil acidity
B. Water absorption rate
C. Soil nitrogen levels
D. Organic matter percentage
Percolation tests determine how quickly water infiltrates the soil.
5. What is the minimum setback from a potable water well for a
conventional septic system in Arizona?
A. 25 feet
B. 50 feet
C. 100 feet
D. 500 feet
Arizona regulations require at least 100 feet of separation.
6. What is the purpose of an effluent filter?
A. Reduce odors
B. Prevent solids from exiting the tank
C. Increase aeration
D. Remove pathogens
Effluent filters trap fine solids before they reach the dispersal system.
7. Which component distributes effluent evenly in a gravity system?
, A. Chlorination unit
B. Surge tank
C. Distribution box
D. Transfer pump
Distribution boxes split flow evenly across trenches.
8. What type of soil is generally unsuitable for a leach field?
A. Loamy sand
B. Clay
C. Sandy loam
D. Gravel
Clay soils have very low permeability and fail to absorb effluent
sufficiently.
9. What is the typical minimum septic tank capacity for a three-
bedroom home in Arizona?
A. 500 gallons
B. 750 gallons
C. 1,000 gallons
D. 1,250 gallons
Standard sizing guidelines recommend at least 1,000 gallons.
10. What is the main purpose of the leach field?
A. Remove solids
B. Aerate wastewater
C. Disperse effluent into the soil
D. Grind organic matter
The dispersal field allows effluent to filter naturally through soil.
