VA Master AOSS Installer Exam Prep
Q1. Who regulates onsite sewage system installation in Virginia?
• A) Virginia Department of Environmental Quality (DEQ)
• B) Virginia Department of Health (VDH)
• C) U.S. Environmental Protection Agency (EPA)
• D) Virginia Department of Transportation (VDOT)
Answer: B) Virginia Department of Health (VDH)
Explanation: The VDH oversees onsite sewage systems under the
Virginia Sewage Handling and Disposal Regulations (12VAC5-610). DEQ
regulates wastewater treatment plants but not onsite sewage systems.
Q2. True or False: A Master Installer license allows you to install both
conventional and alternative onsite sewage systems.
Answer: True
Explanation: A Master Installer license authorizes the installation of
conventional systems and Alternative Onsite Sewage Systems (AOSS),
while a Journeyman may be limited depending on certification.
Q3. Which regulation specifically governs Alternative Onsite Sewage
Systems (AOSS) in Virginia?
• A) 12VAC5-610
• B) 12VAC5-613
• C) 40 CFR 503
, • D) 9VAC25-870
Answer: B) 12VAC5-613
Explanation: The AOSS Regulations (12VAC5-613) establish
performance requirements, operation, and maintenance for alternative
systems. The 12VAC5-610 governs conventional systems.
Q4. How often must an AOSS be inspected by a licensed operator in
Virginia (unless otherwise required by permit)?
• A) Every 6 months
• B) Once per year
• C) Every 3 years
• D) Once every 5 years
Answer: B) Once per year
Explanation: Virginia regulations require AOSS inspections at least
annually to ensure performance, safety, and public health protection.
Q5. Which professional is responsible for certifying that an alternative
system has been installed according to approved plans?
• A) VDH District Health Department
• B) Licensed Soil Scientist
• C) Master Installer
• D) Professional Engineer
Answer: C) Master Installer
Explanation: The Master Installer must certify proper installation
before VDH approval. Engineers and soil scientists design/evaluate, but
the installer signs off on installation.
Section 2: Design and Installation Principles
Q6. The minimum slope required for gravity flow sewer pipe in a
sewage system is generally:
, • A) 1% (1/8 in. per ft)
• B) 2% (1/4 in. per ft)
• C) 5%
• D) No slope is required
Answer: B) 2% (1/4 in. per ft)
Explanation: To maintain gravity flow and prevent solids settling, a
slope of 1/4 inch per foot is standard.
Q7. True or False: Alternative systems are always preferred over
conventional septic drainfields.
Answer: False
Explanation: Alternative systems are only required when site/soil
limitations prevent use of a conventional system. They are typically
more complex and costly.
Q8. Which of the following is an example of an Alternative Onsite
Sewage System?
• A) Conventional trench system
• B) Pressure-dosed shallow placed system
• C) Drip dispersal system
• D) All of the above
Answer: D) All of the above
Explanation: Alternative systems include shallow-placed trenches, drip
dispersal, peat filters, textile filters, ATUs, and pressure-dosed
systems.
Q9. Which component ensures even distribution of effluent in a
pressure-dosed AOSS?
• A) Gravity
• B) Distribution box
• C) Dosing pump
• D) Septic tank baffle
, Answer: C) Dosing pump
Explanation: A dosing pump pressurizes effluent through laterals,
ensuring uniform distribution across the drainfield.
Q10. The minimum setback of an onsite sewage system from a private
drinking water well in Virginia is:
• A) 50 feet
• B) 75 feet
• C) 100 feet
• D) 200 feet
Answer: C) 100 feet
Explanation: VDH regulations require a 100 ft separation between
septic systems and private wells to prevent groundwater
contamination.
Section 3: Soil Science & Site Evaluation
Q11. True or False: Clay soils generally have higher permeability than
sandy soils.
Answer: False
Explanation: Sandy soils have high permeability due to large pore
spaces; clay soils have low permeability and retain water.
Q12. Which soil horizon is typically most suitable for effluent
dispersal?
• A) O horizon (organic)
• B) A horizon (topsoil)
• C) B horizon (subsoil)
• D) C horizon (parent material)
Answer: B) A horizon (topsoil)
Explanation: The A horizon supports microbial activity that helps
treat wastewater, provided it has good permeability and depth.
Q1. Who regulates onsite sewage system installation in Virginia?
• A) Virginia Department of Environmental Quality (DEQ)
• B) Virginia Department of Health (VDH)
• C) U.S. Environmental Protection Agency (EPA)
• D) Virginia Department of Transportation (VDOT)
Answer: B) Virginia Department of Health (VDH)
Explanation: The VDH oversees onsite sewage systems under the
Virginia Sewage Handling and Disposal Regulations (12VAC5-610). DEQ
regulates wastewater treatment plants but not onsite sewage systems.
Q2. True or False: A Master Installer license allows you to install both
conventional and alternative onsite sewage systems.
Answer: True
Explanation: A Master Installer license authorizes the installation of
conventional systems and Alternative Onsite Sewage Systems (AOSS),
while a Journeyman may be limited depending on certification.
Q3. Which regulation specifically governs Alternative Onsite Sewage
Systems (AOSS) in Virginia?
• A) 12VAC5-610
• B) 12VAC5-613
• C) 40 CFR 503
, • D) 9VAC25-870
Answer: B) 12VAC5-613
Explanation: The AOSS Regulations (12VAC5-613) establish
performance requirements, operation, and maintenance for alternative
systems. The 12VAC5-610 governs conventional systems.
Q4. How often must an AOSS be inspected by a licensed operator in
Virginia (unless otherwise required by permit)?
• A) Every 6 months
• B) Once per year
• C) Every 3 years
• D) Once every 5 years
Answer: B) Once per year
Explanation: Virginia regulations require AOSS inspections at least
annually to ensure performance, safety, and public health protection.
Q5. Which professional is responsible for certifying that an alternative
system has been installed according to approved plans?
• A) VDH District Health Department
• B) Licensed Soil Scientist
• C) Master Installer
• D) Professional Engineer
Answer: C) Master Installer
Explanation: The Master Installer must certify proper installation
before VDH approval. Engineers and soil scientists design/evaluate, but
the installer signs off on installation.
Section 2: Design and Installation Principles
Q6. The minimum slope required for gravity flow sewer pipe in a
sewage system is generally:
, • A) 1% (1/8 in. per ft)
• B) 2% (1/4 in. per ft)
• C) 5%
• D) No slope is required
Answer: B) 2% (1/4 in. per ft)
Explanation: To maintain gravity flow and prevent solids settling, a
slope of 1/4 inch per foot is standard.
Q7. True or False: Alternative systems are always preferred over
conventional septic drainfields.
Answer: False
Explanation: Alternative systems are only required when site/soil
limitations prevent use of a conventional system. They are typically
more complex and costly.
Q8. Which of the following is an example of an Alternative Onsite
Sewage System?
• A) Conventional trench system
• B) Pressure-dosed shallow placed system
• C) Drip dispersal system
• D) All of the above
Answer: D) All of the above
Explanation: Alternative systems include shallow-placed trenches, drip
dispersal, peat filters, textile filters, ATUs, and pressure-dosed
systems.
Q9. Which component ensures even distribution of effluent in a
pressure-dosed AOSS?
• A) Gravity
• B) Distribution box
• C) Dosing pump
• D) Septic tank baffle
, Answer: C) Dosing pump
Explanation: A dosing pump pressurizes effluent through laterals,
ensuring uniform distribution across the drainfield.
Q10. The minimum setback of an onsite sewage system from a private
drinking water well in Virginia is:
• A) 50 feet
• B) 75 feet
• C) 100 feet
• D) 200 feet
Answer: C) 100 feet
Explanation: VDH regulations require a 100 ft separation between
septic systems and private wells to prevent groundwater
contamination.
Section 3: Soil Science & Site Evaluation
Q11. True or False: Clay soils generally have higher permeability than
sandy soils.
Answer: False
Explanation: Sandy soils have high permeability due to large pore
spaces; clay soils have low permeability and retain water.
Q12. Which soil horizon is typically most suitable for effluent
dispersal?
• A) O horizon (organic)
• B) A horizon (topsoil)
• C) B horizon (subsoil)
• D) C horizon (parent material)
Answer: B) A horizon (topsoil)
Explanation: The A horizon supports microbial activity that helps
treat wastewater, provided it has good permeability and depth.
