"I feel that my greatest strength is my work ethic and it's been a strength that I've demonstrated from a young age working in a mechanic shop through high school. It has always been ingrained in me that I need to give 100% to my employer every moment I am on the job. This dedication has helped me as a water treatment operator because this job is demanding, requires attention to detail, and requires me to be a safe worker. A strong work ethic keeps me and my team safe and helps to ensure high-quality water leaves my facility."

This is a very open-ended question and there are many routes you can take to answer. If you confidently feel that your biggest strength for the job is the particular on-the-job experience you have, you can certainly talk about that and sell your interviewer the fact that you are the most qualified for the job. If you feel like your greatest strength comes from your work ethic or personality, confidently speak to why this will help you so much as a water treatment operator. No matter how you answer, be sure to give an example of a time you were recognized for displaying this strength.