The information provided is largely based on historical records supplemented, in some cases, by information acquired by observations or excavations conducted by City agencies. ‘Historical records’, for purposes of the map, are the latest plumbing records filed by a licensed master plumber for your property. ‘Observations’ are visual inspections at the meter inside your home. ‘Excavations’ are external visual inspections at the point where your water service line connects with the City-owned water main in the street. It is important to note that DEP is unable to confirm whether the type of material recorded represents the material of the entire length of your service line.