- 1904
- founded in New York City by Nicholas S. Hill, Jr., one of the nation's pioneers in the field of waterworks and sanitary engineering.
- 1919
- William Seifert joins firm
- 1921
- George H. Buck joins firm
- 1929
- Charles Jost joins firm
- 1929
- design and construction of Oradell Reservoir Dam, Oradell, NJ
- 1933
- design and construction of Elizabethtown Water Company, Raritan-Millstone Water Treatment Plant, Bound Brook, NJ
- 1939-1972
- George H. Buck, President
- 1945
- assisted with the formation and served as consulting engineers for the Puerto Rico Aqueduct and Sewer Authority through 1965 Offices at 112 East 19th Street, New York City
- 1958
- design and construction of DeForest Lake Dam, Hackensack River, Clarkstown, NY
- 1963
- design and construction of the Haworth Water Treatment Plant (50 MGD), Haworth, NJ
- 1965-1975
- Offices at 429 Sylvan Avenue, Englewood Cliffs, NJ
- 1966
- design and construction of Lake Tappan Dam, Hackensack River, River Vale, NJ
- 1968
- design and construction of the Carl J. Olsen Water Treatment Plant (30 MGD), Edison, NJ
- 1972-1986
- Domenic J. Pulice, President
- 1975-1985
- Offices at 140 Sylvan Avenue, Englewood Cliffs, NJ
- 1984
- design and rehabilitation of the Woodcliff Lake Dam, Hillsdale, NJ
- 1985-2000
- offices at 30 Park Place, Paramus, NJ
- 1986-1991
- Frank J. DeMicco, President
- 1988
- design and construction of the Haworth Water Treatment Plant Expansion (200 MGD), ozone/direct filtration
- 1991-1998
- Guido von Autenried, President
- 1993
- design and construction of the Park Avenue Well Field Air<br />Stripping Facility (12 MGD) in association with Camp Dresser & McKee (CDM)
- 1996
- design and construction of the Canal Road Water Treatment Plant (40 MGD, expandable to 200 MGD) in association with Camp Dresser & McKee
- 1999-present
- Ronald von Autenried, President
- 2000-present
- Offices at 65 Oak Street, Norwood, NJ
