The resulting reservoir, which was finally placed into service in 1911, holds a mere 900 million gallons (3.4 million m³) of water at full capacity, making it the smallest reservoir in New York City's water supply that is not within the city itself. It also has a drainage basin that takes up only 8 square miles (12.8 km²) of the Croton Watershed, which it is in. This basin includes the lakes, streams, rivers, and other bodies of water that flow into the reservoir. This includes the beginning portion of the East Branch of the Croton River, which is not impounded.
The Diverting Reservoir is connected to the nearby Croton Falls Reservoir via a channel and dividing weir. Water usually passes freely between these two reservoirs. The water in Diverting Reservoir flows into the continuation of the East Branch of the Croton River, and then into the Muscoot Reservoir, the collecting point for the water from most of the reservoirs in the Croton Watershed. It continues into the New Croton Reservoir, the final collecting point, and then continues into the New Croton Aqueduct. It flows into The Bronx, and through the Jerome Park Reservoir, before flowing through Manhattan, where it meets up with the Catskill Aqueduct, then through Brooklyn and Staten Island, where it comes to a halt.
In January 2007, the New York City Department of Environmental Protection reportedly began a $74 million project of improvements to the Croton Falls Reservoir and the Diverting Reservoir. (See Journal-News article dated Feb. 28, 2007) The upgrading and rehabilitation is part of the city's effort to comply with state and federal dam safety regulations. The work at the Diverting Reservoir includes new valves and pipes, along with redoing the spillway and some of the concrete surfaces on the -high dam. The connecting channel between the two reservoirs will be emptied, inspected and dredged. Construction at both sites is expected to continue until Jan. 31, 2010.