How to deal with neglectful cat owners?

There is this cat who lives across from where I live. She is presumably fixed because I believe she came from a shelter because of her very friendly temperament. Her owner put her out on the street with no water and no shelter aside from the outside porch on the neighbors side and the occasional times the inside porch is open. She gets very little human interaction. she is well fed, but I can't be sure is she catches her meals or if he feed her. I own, or am owned by 4 very loving cats and I worry about those who mistreat their "pets". How can I get in contact with the ASPCA or animal control to educate these people or have their animal put in a better place. I don't want them to know it was me who turned them in, I don't need trouble. btw I live in south jersey and have very little knowledge about how the system works.