By asking this question, an employer is trying to learn more about what you value in a job and its work environment. You should avoid answers related to pay or perks. This question is also used to gauge what you know about the government agency you are interviewing with.
Example: “I’ve always been drawn to opportunities that allow me to serve other people. I became interested in your agency after being inspired by your agency’s motto—’To provide joy and opportunities for learning to all ages—and I’ve seen how the different community programs offered by parks and recreation have positively impacted the citizens of Louden County.”