Our townhome community is responsible for fire hydrants?

Our Somerset County, NJ Townhome Community just got told we are "responsible for the fire hydrants" in our development but with no details on what this means. The township is notoriously not forthcoming with information, especially citations of municipal ordinances, statutes and other codes. Previously, the town has come out to flush the hydrants and no mention was ever made of this in the 20+ years the development has been around. Does anyone know of a similar situation? Thanks!