Your web browser is out of date. Update your browser for more security, speed and the best experience on this site.

Update your browser

all things water®

Contact Us

498 Seventh Ave, 11th Floor
New York, NY 10018

(212) 539-7000

The Hazen Legacy

Allen Hazen, a pioneer in fluid hydraulics, developed an equation used commonly to this day by engineers all over the world in calculating a system's water flow. Allen's son, Richard, joined Alfred Sawyer in forming a place where engineers were free to pursue solutions in the best interest of clients and the public. The Hazen legacy of living by our values and advancing water science and practice continues at the firm to this day.

1902: Allen Hazen co-develops the Hazen-Williams equation, which is used in the design of water pipe systems such as fire sprinkler systems, water supply networks, and irrigation systems.

Hazen headshot
1904: Allen Hazen recommends the filtration of the Croton water supply for New York City. In 2015, Hazen staff led the commissioning of a new filtration plant on that water supply.
1908: President Theodore Roosevelt sends Allen Hazen as part of a panel of expert engineers to inspect the construction progress on the Panama Canal with President-Elect William H. Taft.
Hazen mag cover

1937: Richard Hazen graduates Harvard University with an MS in Sanitary Engineering and begins his career as a consulting engineer.

Richard Hazen begins private practice in New York City in 1950, convincing Alfred Sawyer to join him a year later to form Hazen and Sawyer.

Old logo
1 liberia pic2

1952: One of the first projects undertaken by Hazen and Sawyer was a major infrastructure improvement program in Monrovia, Liberia.


1956: The City of Greensboro, North Carolina, is one of Hazen and Sawyer's longest standing clients. Projects for Greensboro such as the Lake Brandt Dam influenced our expansion into the Mid-Atlantic states.

2 Springwells Low lift outl

1957: Our work on the Springwells WTP project in Detroit led us to open our first branch office there in the mid-1950s.

1961: Our first project for the New York City Department of Environmental Protection was at Tallman Island WWTP. Since then we have worked on countless major programs and projects for the DEP.

1962: Our work on the New York World’s Fair included design of 8 miles of new sewer and 9 miles of stormwater system over a 600-acre site, as well as water quality analysis and treatment for lakes in Flushing Meadow Park used for aquatic sports and exhibitions.

1979: For the Miami-Dade County Water and Sewer Department in Florida, we completed work on a new 60-mgd plant to serve the northern portion of the County. Known today as the North District Wastewater Treatment Plant (pictured here in 1977), we have subsequently provided design and construction management services for expansion of the plant to 60, 80, and 100 mgd.

Reuse fl 1

Hazen conducted master planning and implementation of the first regional reuse system for the Loxahatchee River District in South Florida in 1986.

Reuse fl 2

Over thirty years later, we’re still on the cutting edge of water reuse in Florida, conducing pilot studies to investigate alternative technologies to meet statewide ocean outfall legislation.

2015: The 290-mgd Croton Water Filtration Plant (originally recommended by Allen Hazen in 1904) is constructed entirely under a driving range in the Bronx, providing roughly 30 percent of New York City's current daily water needs and critical system flexibility and redundancy.

70 years after our founding, our work continues to make an impact on communities across the country and the world.