Elmwood Park began as the Dundee Lake section of Saddle River Township, broke away as East Paterson in 1916, added Rosemont in 1917, and took its current name on January 1, 1973. The 2023 American Community Survey puts the median year built at 1957. City-Data separates the two housing types: a median of 1955 for houses and condos, and 1968 for apartments.
The mix matters as much as the age. The same survey data shows 51.8% single-family and 48.2% multi-family, and 42.6% of homes are rented. City-Data counts 2,161 units in two-unit buildings, about 28% of its total, with more in three- and four-unit buildings and in larger complexes.
A two-family house often means two of everything: two water heaters, two heating systems and two thermostats, usually in one basement and usually draining to one sewer line to the street. When one unit's equipment fails, it is worth checking the age of the other unit's while someone is already there. Owners who rent out a unit should know where each unit's shutoffs are before there is a leak.
Most houses here run on gas: City-Data shows 84.1% of houses and condos on utility gas, with 6.9% on fuel oil or kerosene. In a home from the 1950s the furnace or boiler has often been replaced at least once, while the ductwork, radiators and piping behind it are often older. If you are still on oil and gas is on your street, an oil-to-gas conversion is worth pricing.
PSE&G is replacing aging cast iron gas pipes in Elmwood Park with plastic or coated steel, with that work expected to run through 2027, and it connects service lines and meters to the new main. Its work stops at the meter. Piping on the house side belongs to the owner, and that is where a new range or dryer calls for gas line work.