The project involved the design of a new 30,000 SF water treatment facility located on a 13 acre lot in Harrison, NY. The Rye Lake Water Treatment Plant provides water filtration (20 million gallons per day) to Westchester Joint Water Works to Mamaroneck, Harrison, Rye, New Rochelle, and Larchmont. The Rye Lake facility was unfiltered and the water supply was treated with chlorine, fluoride, corrosion inhibitor, and caustic soda for pH control.

HVAC system design consisted of hot water boiler, pumps, heating and ventilating units, air conditioning units, dehumidification unit, fans, related supply, return and exhaust ductwork, hot water piping, natural gas fuel systems and control systems. The HVAC systems were designed in accordance with the New York State Building Code, the New York State Energy Code, ASHRAE Standard 90A-1980, Energy Conservation in New Building Design and ASHRAE Standard 62-1989.

Ventilation was provided to meet the latest code requirements and to satisfy design criteria for the various facilities such as, general process areas, chemical areas and specialized chemical areas. Air conditioning was provided for the offices, laboratory rooms, locker rooms, control rooms, and electrical rooms.

Plumbing and fire protection system design included domestic cold and hot water, sanitary sewer, and plumbing fixtures. Waste water from the lower level floor was collected in a sump pit and pumped to a sanitary drain. Storm water drain and partial roof were also incorporated into the design. Main water source piping ran underground from the southwest side of the building, and was distributed through three backflow preventers. The three backflow preventers were dedicated to serve the domestic water, process water, and fire protection systems.

Other systems included eight inside and one outside emergency shower/eye wash (ES/EW) stations in the building.  Each station was equipped with a thermostatic mixing valve providing 85 F water to the ES/EW stations. The thermostatic mixing vales receive cold and hot (110 F.) water from the domestic water loops. Two inline circulating pumps located in the maintenance room, maintaining  the  110 F temperature in the  domestic hot water loop in the entire building.


Westchester Joint Water Works


Hazen & Sawyer


30,000 SF


Mechanical Engineering
Plumbing Engineering
Fire Protection Engineering

Construction Cost

$35 Million

Completion Date



Mr. Richard Peters
Hazen & Sawyer
498 Seventh Avenue
New York, NY 10018
(212) 539-7134