Well, that is not good. I doubt your homeowners will cover flood damage. I would get your agent on the line pronto. There are certainly rules regarding flood retention structures, and if you sic the DNR water resources guys on them, they will be required to build it to code. In the meantime, document the heck out of it - make sure there are pictures of before, in case "after" happens. A civil lawsuit may be your only recourse in that case. Puke