Wastewater Operator Certification program

Wastewater treatment plants (WWTP) serve an essential function to protect public health and the environment from contaminated water leaving homes and businesses. Competent, trained, and certified operators must run these plants. We assure qualified operators fill this role through evaluating certification requirements and ongoing professional training.

Formal public comment period

We invite comments to the proposed changes to Chapter 173-230 WAC Certification of Operators of Wastewater Treatment Plants until May 1, 2019. The proposed changes establish a fee schedule as directed by the Legislature in 2018. In addition, as this is the first update to the program since 1999, we are proposing multiple changes, including:
  • Adding Group II, Group III, and Group IV Operator-in-Training categories.
  • Updating the professional growth requirements.
  • Recognizing newer, more advanced treatment technologies in plant classification.
  • Clarifying and reorganizing rule language where needed.
To learn more, please visit the rulemaking webpage

How do I get certified?


Download application then mail it

or request an application be mailed to you. 

Remember to:

  • Type or write clearly in ink.
  • Apply for the level you qualify for.
  • Complete all five pages in full detail.
  • Hand sign and date affidavit (even if you have no operating experience).
  • Include all supporting documents and a $50 application fee.

What happens next?

What exam level do I qualify for?

  • All levels require a high school diploma or GED. Excess WWTP operating experience can substituted for a high school diploma or GED.
  • "Operating experience" means the routine performance of duties, onsite in a WWTP, that affect plant performance or effluent quality.
Certification level Required domestic operating experience and relevant
Allowable substitutions for operating experience

Allowable substitutions for education

Examples of substitutions for excess operating experience with no relevant experience and not enough credits/CEUs

Operator in Training 3 months operating experience 3 relevant credits/CEUs --- ---
Group I 1 yr operating experience --- --- ---
Group II 3 yrs operating experience Up to 1.5 yrs relevant experience, education or portion of both
(1.5 yrs=67.5 credits/CEUs)



Group III 4 yrs operating experience (with at least 2 yrs at a class II or higher plant)


90 credits/CEUs
Up to 2 yrs relevant experience, education or portion of both
(maximum 90 excess relevant credits/CEUs)


Excess operating experience
1 yr for 1st 45 credits/CEUs
3 yrs for last 45 credits/CEUs
(4 yrs excess operating)

6 yrs total operating experience + 29 relevant credits/CEUs

7 yrs total operating experience + 12 relevant credits/CEUs

8 yrs total operating experience + 0 relevant credits/CEUs

Group IV 4 yrs (with at least 2 yrs at a class III or higher plant)


180 credits/CEUs
Up to 2 yrs of relevant experience, education or portion of both
(maximum 90 excess relevant credits/CEUs)
Excess operating experience
1 yr for each 45 credits/CEUs for 1st 90
3 yrs for last 45 credits/CEUs for 2nd 90 credits
(8 yrs excess operating experience)

10 yrs total operating experience + 29 relevant CEUs/credits

11 yrs total operating experience + 12 relevant credits/CEUs

12 yrs total operating experience + 0 relevant credits/CEUs

What counts as relevant experience?

Included but not limited to:

  • Boiler operator
  • Building/equipment maintenance
  • Engineering
  • Environmental or engineering branch of federal, state, county, or local government
  • Environmental or operations consultant  
  • Laboratory technician
  • Machinist
  • Water distribution manager
  • Water treatment plant operator 
  • Welding
  • Wastewater collection operator
  • Wastewater pump operator

To substitute education for operating experience, education credits or Continuing Education Units (CEUs) must be in excess of the required education. 

  • 1 year = 45 quarter credits/CEUs or 30 semester credits
  • 1 month = 4 credits/CEUs

Frequently asked questions

Where to send your application materials:

Correspondence/professional growth documents



Department of Ecology
Wastewater Operator Certification
PO Box 47696
Olympia, WA 98504-7696

Payments (applications and renewals)