pumping at work

So I'm thinking about leaving my current job and applying to other places. Currently I'm a nanny so pumping at work was no issue. She's a mom, she breastfed, she gets it. But how would I go about that at a more company based type job? Do I have to tell them I pump at the interview? I feel like it may hurt my chances. Or wait until I'm offered the job? I'm aware of the laws and they have to allow me time and place to pump. But I'm just not quite sure how to figure that out, who exactly to bring it up to and when. Any experiences appreciated!