Ohio Department of Health (ODH) Home Sewage
Treatment System Installer (STS) exam (based on
rules in Ohio Administrative Code 3701-29)
Questions And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant Download Pdf
1. A building sewer under OAC 3701-29-12 shall have a minimum
diameter of:
A. 2 inches
B. 4 inches
C. 6 inches
D. 10 inches
It must be at least 4 inches diameter to handle typical domestic
sewage flows.
2. Timed micro-dosing of effluent through a drip distribution system
qualifies for a soil-depth credit of:
A. 6 inches
B. 12 inches
C. 24 inches
D. It does not qualify for a soil depth credit
With timed micro‐dosing systems the rules allow the deeper soil
credit (24″) because of the reduced loading rate.
3. Effluent dosing pumps shall:
A. Be rated for effluent service by the manufacturer
B. Inspected by a plumbing inspector
, C. Used for all systems
D. Be rated for effluent service by the manufacturer
The rule requires dosing pumps to be specifically rated for effluent
service; inspection requirements may vary.
4. The amount of septage applied on a site shall not exceed a volume
determined by the:
A. Number of acres
B. Annual nitrogen application rate required for the crop
C. Population of the township where it is applied
D. Size of the septage hauler truck
Land application of septage is regulated based on nitrogen loading
rates to avoid excessive nutrient discharge.
5. A STS must be ____ feet from a lake or other surface
impoundment of water.
A. 100
B. 50
C. 25
D. 10
Limitations for separation to surface water bodies often require at
least 10 feet unless a more protective separation is specified.
6. ____ distribution shall be required when applying effluent to the
sand-fill infiltrative surface of a soil absorption component.
A. Pressure
B. Drip
C. Either A or B
D. Gravity
When effluent is applied to a sand‐fill infiltrative surface the rule
, allows gravity distribution under certain conditions instead of
pressure or drip.
7. Prior to accepting an application for permit to install or alter a STS,
the board of health shall require:
A. A site review
B. Floor plan of the building
C. Design from a professional surveyor
D. A site review
The health department must perform a site review to ensure the
lot/soil is suitable before issuing a permit.
8. To demonstrate competency, an installer shall:
A. Maintain status as a certified installer of onsite wastewater
treatment systems (CIOWTS) through the NEHA
B. Complete at least six continuing education hours per calendar
year
C. Either A or B
D. Provide references
The rule allows either certification through NEHA or completion of
continuing education to show competency.
9. The record of site and soil characteristics for each soil boring or
excavation shall include:
A. Site descriptions
B. Detailed soil profile descriptions
C. Documentation of any relevant surface hydrology, geologic and
hydrogeologic risk factors
D. All of the above
Treatment System Installer (STS) exam (based on
rules in Ohio Administrative Code 3701-29)
Questions And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant Download Pdf
1. A building sewer under OAC 3701-29-12 shall have a minimum
diameter of:
A. 2 inches
B. 4 inches
C. 6 inches
D. 10 inches
It must be at least 4 inches diameter to handle typical domestic
sewage flows.
2. Timed micro-dosing of effluent through a drip distribution system
qualifies for a soil-depth credit of:
A. 6 inches
B. 12 inches
C. 24 inches
D. It does not qualify for a soil depth credit
With timed micro‐dosing systems the rules allow the deeper soil
credit (24″) because of the reduced loading rate.
3. Effluent dosing pumps shall:
A. Be rated for effluent service by the manufacturer
B. Inspected by a plumbing inspector
, C. Used for all systems
D. Be rated for effluent service by the manufacturer
The rule requires dosing pumps to be specifically rated for effluent
service; inspection requirements may vary.
4. The amount of septage applied on a site shall not exceed a volume
determined by the:
A. Number of acres
B. Annual nitrogen application rate required for the crop
C. Population of the township where it is applied
D. Size of the septage hauler truck
Land application of septage is regulated based on nitrogen loading
rates to avoid excessive nutrient discharge.
5. A STS must be ____ feet from a lake or other surface
impoundment of water.
A. 100
B. 50
C. 25
D. 10
Limitations for separation to surface water bodies often require at
least 10 feet unless a more protective separation is specified.
6. ____ distribution shall be required when applying effluent to the
sand-fill infiltrative surface of a soil absorption component.
A. Pressure
B. Drip
C. Either A or B
D. Gravity
When effluent is applied to a sand‐fill infiltrative surface the rule
, allows gravity distribution under certain conditions instead of
pressure or drip.
7. Prior to accepting an application for permit to install or alter a STS,
the board of health shall require:
A. A site review
B. Floor plan of the building
C. Design from a professional surveyor
D. A site review
The health department must perform a site review to ensure the
lot/soil is suitable before issuing a permit.
8. To demonstrate competency, an installer shall:
A. Maintain status as a certified installer of onsite wastewater
treatment systems (CIOWTS) through the NEHA
B. Complete at least six continuing education hours per calendar
year
C. Either A or B
D. Provide references
The rule allows either certification through NEHA or completion of
continuing education to show competency.
9. The record of site and soil characteristics for each soil boring or
excavation shall include:
A. Site descriptions
B. Detailed soil profile descriptions
C. Documentation of any relevant surface hydrology, geologic and
hydrogeologic risk factors
D. All of the above
