Jerome Park Reservoir Gatehouse No.5 at Goulden Avenue and West 205th Street, July 31, 2015. The visible, above-ground part was built by the WPA in 1939, renovated in 1965 and again in 2012-2015 (it was hidden from view until just recently). It contains a chlorination facility, chlorine storage rooms, 17 upright hand wheels that control water flow through sluice gates, the Reservoir rescue skiff, an office, and an employee lounge.[1] Gate House No.5 is the main gate house, and is constructed in the East Wall of the reservoir. The Old Croton Aqueduct passes through it, and it is the terminus of the horseshoe-arched, gravity portion of the New Croton Aqueduct (via the Jerome Park Branch)[2].

Reference:

1. Final Supplemental Environmental Impact Statement for the Croton Water Treatment Plant, nyc.gov archive, Section 8.2 of The Croton Water Filtration Plant Project: Final Supplemental Environmental Impact Statement, July 16, 2004.
2. National Register of Historic Places Registration Form for Jerome Park Reservoir, March 28, 2000, Section 7, Page 5 (Lehman College historical archive).