Construction on the Oradell Reservoir began in 1901 by the dredging of a mill pond. The mill pond dam was replaced in 1911 by a low timber-crib dam that increased reservoir storage. In 1921, a 22-foot (6.7 m) high concrete Oradell Reservoir Dam was built to expand reservoir storage even more. The reservoir was completed in 1923. The Oradell Reservoir and its tributaries are currently protected with Category 1 water purity status in New Jersey. The reservoir is managed by United Water New Jersey, a unit of United Water, a private utility. It provides drinking water for an estimated 750,000 residents of Bergen and Hudson counties.