Established: 11/90
Revised: 05/07
FLSA: Exempt
EEO: 3



Under direction, to conduct plan reviews and on-site soil investigations to determine the feasibility of septic systems, proposed grading projects and erosion control measures; to lead the work of Soil Scientists; and to do other work as required.


The Soils Section within Water Environment Services is responsible for administering DEQ rules and Clackamas County ordinances and regulations.

The Soil Scientist, Senior is responsible for 1) evaluating proposed sites for on-site sewage disposal or inspecting newly constructed, existing or failing on-site sewage disposal systems consistent with DEQ codes and County ordinances, (2) evaluating grading permit plans and inspecting grading sites for compliance with County ordinances, (3) evaluating erosion control plans for consistency with local and regional codes and ordinances, and conducting field inspections of same as necessary, and (4) assigning inspection workloads, developing and implementing section training needs, and resolving technical and code interpretation questions. The Soil Scientist, Senior reports to the Soils Program Supervisor, who has full supervisory responsibility for Soils Section staff.

The Soil Scientist, Senior is distinguished from the Soil Scientist by the latter's lack of responsibility for lead work and resolving technical and code interpretation questions.


Duties may include but are not limited to the following:

  1. Assigns inspection section work load; develops and implements section training sessions; resolves technical and code interpretation questions.
  2. Reviews and approves or denies on-site sewage disposal permits, grading permits, erosion control plans and building permits requiring on-site sewage disposal; answers questions regarding septic tank, grading or erosion control permit processes, soil feasibility studies, soil investigations, existing septic system reviews and variance procedures.
  3. Conducts on-site soil investigations and feasibility studies; inspects grading and erosion control facilities; gathers information to determine whether the site is suitable for a septic system; drills test holes, analyzes soil samples and determines if soil characteristics, slope, surface water, and potential ground water sources meet current standards.
  4. Designs septic systems based on site and soil characteristics, Department of Environmental Quality rules and County codes.
  5. Reviews planning department applications for consistency with sewage disposal, erosion control or grading regulations.
  6. Provides technical guidance to the general public regarding septic system installations, grading codes and erosion control, site characteristics and repair options for failing septic systems via the telephone, in person or in writing.
  7. Investigates complaints or observations of State, regional or local environmental law violations.
  8. Prepares reports and completes correspondence regarding field investigations; maintains records for septic, grading and erosion control inspections and certificates and other programs.


Working knowledge of: Principles of lead work supervision; Department of Environmental Quality regulations; Clackamas County Excavation and Grading ordinance; Tualatin basin erosion control requirements; general principles of geology, hydrology and soil science; septic design, septic system design standards and practices; basic math and statistics; County field inspection procedures and practices; County permit process and zoning regulations; basic math, English grammar and composition.

Skill to: Lead the work of assigned personnel; interpret scale drawings; determine soil profiles; discriminate between functional, marginal and non-functional septic systems; provide advice on septic system installations; determine appropriate grading measures in a variety of circumstances, interpret grading and erosion control plans based on applicable codes; communicate effectively, both orally and in writing; prepare detailed reports; establish and maintain effective working relationships.


Duties are performed both indoors and outdoors; field investigations may require moderately strenuous physical activity.


Registration by the State of Oregon as an Environmental Health Specialist or Wastewater Specialist, Engineering Geologist, and/or recognition by the American Registry of Certified Professionals in Agronomy, Crops and Soils as a “Certified Professional Soil Scientist or Specialist.

Driving is required for County business on a regular basis or to accomplish work. Incumbents must possess a valid driver's license, and possess and maintain an acceptable driving record throughout the course of employment.


Any satisfactory combination of experience and training that demonstrates possession of the required knowledge and skills.