You can contact and let them know, there are forms usually on the website for you to do this. But it usually takes about 3-4 months to see a new job get the wages garnished. about 1 month for the employer to notify the state that they have a new employee and, 1 month for the dept to find it on that list and then another month of paperwork to get the wages garnished. This is all behind the scenes. Plus, some jobs hold back the first 2 weeks of pay so it's possible to work nearly and entire month and not get paid till the end and THAT"s when the 3 month clock starts for the wages to get garnished. It only goes faster if he supplys the garnishment paperwork when he fills out the new hire paperwork. But I rarely see that happen.
Usually NCP who would provide the paperwork don't have a problem paying support.