See a mistake?  If you catch an error in any of our PEST question databases or math workbooks, drop us a line and let us know.  We try to fix errors as quickly as possible.

Free Downloads

At Indigo Water Group, we're committed to helping water and wastewater professionals grow in their careers.  We've developed a ton of sample questions and math workbooks to help study for the operator certification exams.  While these aids are certainly helpful, they don't take the place of hands-on training and studying industry accepted textbooks and materials. 

Personal Exam Self Tester

The Personal Exam Self Tester software or PEST was originally developed by Michael Cornelison of Vellosoft.  Mike has made numerous changes to his great little software program to help support operator training and certification.  The PEST software is not hosted on this web page.  You'll need to visit Mike's website to download the software at http://www.vellosoft.com/pest.exe

Math Workbooks

We've developed several different math workbooks because we understand that many water and wastewater professionals have been practicing in their fields for many years.  It's been a long time since high school algebra!  All of our math books break problems down into different categories and show complete, step by step solutions.  There is always more than one way to get to the right answer, so don't worry if your path doesn't match ours.

Click on the math workbooks tab at the right to reach the download page for our free math workbooks.

"I would just like to take a few moments of your time to thank you for putting those "big books of water and wastewater" on line.  I am currently studying for my level 2 and hopefully then my level 1 later this year.  I had been looking for something like these books - something that explains math in plain English.  I've passed them out to anyone who was interested here at the wastewater treatment plant and everyone was quite impressed.  So once again, a big THANK YOU!!!!"
      - Joseph Pereira, Supervisor Western VA Water Authority

Make a Donation

Developing new PEST Questions and Math Workbooks takes a considerable amount of time.  As a business, we must balance development time for FREE products that help people against the need to pay our bills.  If these products are important and helpful to you, please consider making a small donation towards their development.