contaminant intrustion in water distribution systems an ingress model Mansour Rezaei Naser | http dx doi org10 5942jawwa 2013 105 0001 Journal American Water Works Association Peer Reviewed E 2 9 2013 © American Water Works Association Contaminant intrusion is one of the potential causes of water quality failure in a water distribution system (WDS) Because exposure to a contaminant intrusion may have adverse effects on public health, the Research and Information Collection Partnership (con.