Healthy Homes, Part 10: On-site Wastewater Treatment Course

Welcome to InterNACHI's free online "Healthy Homes, Part 10: On-site Wastewater Treatment Course." This is part 10 of a 14-part Certified Healthy Homes Inspector certification program. This course is provided by our accredited college at


This course aims to teach students about the treatment of human waste, including on-site wastewater treatment systems. 


Upon successful completion of this course, students will be able to:

  • discuss the importance of septic tanks;
  • describe the public health and sanitation issues regarding septic tanks;
  • explain the methods used in evaluating septic tanks;
  • distinguish between various forms of septic tank systems;
  • describe alternative forms of septic tank systems; and
  • explain general maintenance and care for septic systems; 
  • perform an inspection related to treating human waste; 
  • generate observations related to inspecting wastewater treatment; and 
  • produce written reports related to observations conducted at a house.

Course includes:

  • 20 InterNACHI® CE credit hours
  • 8,233 words
  • 20 quiz questions in four quizzes
  • Inspection and writing assignment
  • Research and writing assignment
  • 20-question final exam
  • Certificate of Completion 

You will learn the following topics:

  • Short history
  • On-site systems
  • Treatment of human waste
  • On-site wastewater treatment systems
  • Septic tank systems
  • Absorption field site evaluation
  • Absorption field trench
  • Alternative septic tank systems
  • Mound systems
  • Low-pressure pipe systems
  • Plant-rock filter systems
  • Maintaining on-site wastewater treatment systems
  • Do's and dont's 
  • Symptoms of septic system problems
  • Septic tank inspection
  • Inspection process
  • Scum measurement
  • Sludge measurement


Healthy Homes, Part 10: On-site Wastewater Treatment Course
Course #4820, Student Catalog 

Student WorkTime CalculationEstimated Clock Hour Time for the Average Student
Attendance for "Seat Time" 1# of minutes of student attendance / 501.6
Participation in Learning Activities 2# of minutes of online student participation / 500.5
Interactivity 3# of minutes of student interactivity / 500.5
Reading the Course Text 4# of words in the course / 100 words per minute / 501.6
Reading the Course Textbook 5# of words in the book / 100 words per minute / 500.8
Academic Engagement 6# of words in the course / 100 / 500.5
Direct Communication 7# of minutes of communication / 500.5
Instructional Video Learning 8# of minutes of video / 500.0
Reinforcement Q & A  9# of questions X 1.85 / 500.5
Writing Assignment of the Inspection  104.0 hours per assignment4.0
Writing Assignment of the Research  114.0 hours per assignment4.0
Academic Activities for an Inspection  128.0 hours for each inspection assignment8.0
Performing an Inspection  138.0 hours for each inspection8.0
Total clock hours
29.0 clock hours
29.0 InterNACHI CE Hours
2.9 CEU

This course has been approved by:

In keeping with InterNACHI's commitment to Continuing Education, this online course is open and free to all members and can be taken repeatedly without limit.

Reminder to members:  InterNACHI's Code of Ethics 1.10 requires that you comply with all government rules and licensing requirements of the jurisdiction where you conduct business.  InterNACHI's courses and Standards generally exceed the Standards of Practice that you are required to abide by locally.