Minnesota Subsurface Sewage
Treatment System Soil Evaluator Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. The primary purpose of a soil evaluation for a Subsurface Sewage
Treatment System (SSTS) site is to determine:
A. The property tax value of the land
B. The soil’s ability to treat and disperse wastewater
C. The age of the existing septic tank
D. The number of occupants in the building
Answer: B. The soil’s ability to treat and disperse wastewater
The soil evaluation identifies soil characteristics such as texture, structure,
depth, and limiting conditions that determine whether wastewater can be
properly treated and dispersed.
, 2. In an SSTS soil evaluation, the soil horizon that is most important for
wastewater treatment is usually the:
A. Surface organic layer only
B. Unsaturated soil layer above the limiting condition
C. Bedrock layer
D. Gravel fill layer only
Answer: B. Unsaturated soil layer above the limiting condition
The unsaturated soil zone provides biological treatment and filtration
before wastewater reaches groundwater or restrictive layers.
3. A soil evaluator examining a soil profile is primarily looking for:
A. Landscaping quality
B. Soil colors and textures that indicate treatment capability
C. Crop production potential
D. Property boundaries
Answer: B. Soil colors and textures that indicate treatment capability
Soil color, texture, and structure provide information about drainage,
saturation, and suitability for wastewater treatment.
4. A limiting soil condition for an SSTS site includes:
,A. A deep layer of suitable soil
B. A restrictive layer preventing proper infiltration
C. A large building footprint
D. A flat lawn area
Answer: B. A restrictive layer preventing proper infiltration
Restrictive conditions such as bedrock, groundwater, or dense soil layers
can prevent effective wastewater treatment.
5. Soil texture refers to the relative amounts of:
A. Stones and roots
B. Sand, silt, and clay particles
C. Organic matter only
D. Moisture and air
Answer: B. Sand, silt, and clay particles
Soil texture classification is based on the proportion of sand, silt, and clay
particles, which affects water movement.
6. A soil with a high percentage of clay generally has:
A. Very rapid infiltration
B. Low water-holding capacity
, C. Slow permeability and drainage
D. No treatment ability
Answer: C. Slow permeability and drainage
Clay particles create small pore spaces that restrict water movement and
can limit wastewater dispersal.
7. Sandy soils typically have:
A. Rapid infiltration rates
B. Extremely slow movement of water
C. High clay content
D. No oxygen movement
Answer: A. Rapid infiltration rates
Sandy soils have larger pore spaces that allow water to move quickly
through the soil.
8. Soil structure describes:
A. The arrangement of soil particles into aggregates
B. The color of the soil
C. The amount of rainfall
D. The size of the septic tank
Answer: A. The arrangement of soil particles into aggregates
Treatment System Soil Evaluator Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. The primary purpose of a soil evaluation for a Subsurface Sewage
Treatment System (SSTS) site is to determine:
A. The property tax value of the land
B. The soil’s ability to treat and disperse wastewater
C. The age of the existing septic tank
D. The number of occupants in the building
Answer: B. The soil’s ability to treat and disperse wastewater
The soil evaluation identifies soil characteristics such as texture, structure,
depth, and limiting conditions that determine whether wastewater can be
properly treated and dispersed.
, 2. In an SSTS soil evaluation, the soil horizon that is most important for
wastewater treatment is usually the:
A. Surface organic layer only
B. Unsaturated soil layer above the limiting condition
C. Bedrock layer
D. Gravel fill layer only
Answer: B. Unsaturated soil layer above the limiting condition
The unsaturated soil zone provides biological treatment and filtration
before wastewater reaches groundwater or restrictive layers.
3. A soil evaluator examining a soil profile is primarily looking for:
A. Landscaping quality
B. Soil colors and textures that indicate treatment capability
C. Crop production potential
D. Property boundaries
Answer: B. Soil colors and textures that indicate treatment capability
Soil color, texture, and structure provide information about drainage,
saturation, and suitability for wastewater treatment.
4. A limiting soil condition for an SSTS site includes:
,A. A deep layer of suitable soil
B. A restrictive layer preventing proper infiltration
C. A large building footprint
D. A flat lawn area
Answer: B. A restrictive layer preventing proper infiltration
Restrictive conditions such as bedrock, groundwater, or dense soil layers
can prevent effective wastewater treatment.
5. Soil texture refers to the relative amounts of:
A. Stones and roots
B. Sand, silt, and clay particles
C. Organic matter only
D. Moisture and air
Answer: B. Sand, silt, and clay particles
Soil texture classification is based on the proportion of sand, silt, and clay
particles, which affects water movement.
6. A soil with a high percentage of clay generally has:
A. Very rapid infiltration
B. Low water-holding capacity
, C. Slow permeability and drainage
D. No treatment ability
Answer: C. Slow permeability and drainage
Clay particles create small pore spaces that restrict water movement and
can limit wastewater dispersal.
7. Sandy soils typically have:
A. Rapid infiltration rates
B. Extremely slow movement of water
C. High clay content
D. No oxygen movement
Answer: A. Rapid infiltration rates
Sandy soils have larger pore spaces that allow water to move quickly
through the soil.
8. Soil structure describes:
A. The arrangement of soil particles into aggregates
B. The color of the soil
C. The amount of rainfall
D. The size of the septic tank
Answer: A. The arrangement of soil particles into aggregates
