Examinations: On-site wastewater treatment

Required exams

You must pass all of the following exams to get your license:

• The 4-hour On-site Wastewater Treatment System Designer Licensing Exam
• Starting in April 2009, you must also pass a take-home Law and Ethics Exam covering the following Washington State laws and rules:
  • RCW 18.210: On-site wastewater treatment systems – designer licensing
  • RCW 18.235: Uniform regulation of business and professions act
  • WAC 196-30: Fees for on-site wastewater treatment designers and inspectors
  • WAC 196-32: On-site wastewater treatment system designer licenses/inspector certificates of competency
  • WAC 196-33: Rules of professional practices for licensees designing on-site wastewater treatment systems
  • WAC 196-34: Continuing education of licensed professional on-site wastewater treatment system designers and certified inspectors
  If you fail the Law and Ethics exam, you may retake it after you receive notice you didn’t pass.

Exam schedule

Exams are administered each April and October.

Study guides

On-Site Wastewater Treatment System Designer Licensing Examination Study Guide (updated April 2009)

Frequently asked questions

Can I reschedule or withdraw from an exam without paying additional fees?

You may withdraw from a scheduled exam without forfeiting the fee by sending us a written notice no later than 6 weeks before the exam date. The fee submitted with your application will be held until you are scheduled in another exam.

However, if you don’t pass an exam, or don’t take it for any reason, you must pay a re-examination fee before you can be scheduled to take it again.

Will I get my test results?

Because the exam is pass/fail, you won’t receive your exam scores if you pass the test. If you fail the test, we will tell you how many answers you got correct in each content area but won’t tell you which specific answers were incorrect. Scores are usually available 6-8 weeks after the exam.