Water System Operations (WSO)

AWWA's WSO materials lead the industry in operator certification training.

WSO Guidebook Series: Guidance on operator treatment and distribution subject matter principles.

WSO Certification Exam Prep Book & App: Offer practice questions and detailed answer explanations to prepare for the test.

WSO DVDs: Provide in-depth information on water quality treatment principles and practice.

Better for Operators & Students

Based on Certification Levels. All WSO materials are arranged to cover a specific level of experience or subject.

More Affordable. Select only the grade level or subject matter that you need and save.

Made to Pass the Test. All WSO resources meet the latest ABC Need-to-Know criteria.

Enhanced content. The WSO exam prep app and guides both include listings of additional resources.

Made to Pass the Test

AWWA's WSO certification resources are the only widely-used certification-training materials that conform to the latest Association of Boards of Certification (ABC) Need-to-Know criteria. For certification training to meet the highest standards and be applicable to the widest audience, it is crucial that materials be developed in accordance with the latest ABC criteria.

ABC administers the operator certification testing for most of North America.



Practice Exam Questions & Answers

  •  1,400+ all-new questions and answers
  •  Vetted and approved by water industry experts
  •  Arranged by subject matter for easy reference
  •  Pairs with AWWA's Certification Exam Prep App

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Take Studying on the Go

The new AWWA Exam Prep App allows you to take certification preparation with you wherever studying is most convenient. 

  •  See detailed answer explanations
  •  Track your performance 

Download the free app with sample questions. Additional question sets are only $19 each!

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Not quite ready for practice questions? 

Get more training on principles and practices with WSO guidebooks

Bulk Discounts

We offer discounts when you order several copies at a time. These books are ideal for training and course adoption. For more information, contact distribution@awwa.org or call Eric Lovick at 303.347.6210.

Request a Desk Copy

If you are considering adopting any of the WSO Certification books for your courses and would like to see a review copy, please contact distribution@awwa.org

Please provide the following information with your request: Your name, your school, course title, school mailing address, next start date, book requested for review, and expected enrollment.

WSO Video Clips Included in the Book Series

Choose the video player for your book and click the menu logo in the upper left-hand corner to see and select from a list of the book's video clips.


WSO Water Treatment, Grade 1

WSO Water Treatment, Grade 2


WSO Water Treatment, Grades 3 & 4
WSO Water Distribution, Grades 1 & 2

WSO Water Distribution, Grades 3 & 4