Drinking Water

Public health and economic prosperity will always be dependent upon a reliable supply of fresh, clean water. Maintaining this supply presents a steady stream of challenges to utilities, as populations grow and many existing sources of water become stressed by overuse, contamination, and climate change. Utilities also now face increasingly stringent regulations and a public that is more educated on water quality issues than ever before.

The Catskill Delaware UV Disinfection Facility is the world's largest (2,020 mgd) drinking water Ultraviolet Disinfection installation, providing increased public health protection and substantially lower construction and operating costs than a filtration plant.

The LEED certified Bradley Water Treatment Plant in Champaign County, Illinois, is a model of sustainability and was delivering water 21 months from project start.

For the City of Glendale (CA), Hazen and Sawyer is studying ion exchange, adsorptive media, and reduction/coagulation/filtration with microfiltration as treatment technologies for hexavalent chromium and nitrosamines - simultaneously providing criitcal information to inform the regulatory MCL-setting process.

For a USAID-funded project, Hazen and Sawyer led a team in the design and construction management of a project to reduce water losses in Amman, Jordan, restructuring nearly half of Amman's water distribution system.

The 290-mgd Croton WTP is New York City's first water treatment facility. Hazen and Sawyer, in joint venture, prepared conceptual designs, performed environmental impacts studies, prepared preliminary and final designs, and provided start-up operational services for this landmark plant.

Sophisticated water quantity-quality models of an entire water supply system, such as this OASIS-W2 model, can be used to identify the most beneficial and cost-effective alternatives for turbidity reduction.

Hazen and Sawyer worked with the City of Lomita (CA) to improve the taste and odor of a needed groundwater source, making system improvements and identifying a blended water that achieved high levels of customer satisfaction.

Hazen and Sawyer assisted the NYCDEP in designing and implementing long-term rehabilitation of the Gilboa Dam, the Schoharie Reservoir, and the Shandaken Tunnel.

A hydraulic model helped to identify the best combination of scenarios for the greatest overall reduction in water age (and DBP formation) throughout the NYC distribution system.

We regularly use desktop studies, benchscale studies, pilot plant studies, and full-scale utility studies to inform the development of processes that meet and exceed project goals, while minimizing both operating and capital expenditures.

Hazen and Sawyer provided engineering design and construction management services for three 23-mgd Water Treatment Plants in the Dominican Republic that were online 24 months from project start.

The initial construction of the City of Hallandale Beach Membrane Softening Facility included 2-mgd nanofiltration skids with dedicated feed pumps.

Hazen and Sawyer can help you meet these complex challenges while, in many cases, improving efficiency and saving money. We’ve developed solutions for major metropolitan areas including New York City, Washington, D.C., and Amman, Jordan – as well as for many smaller cities, towns and municipalities.


Hazen and Sawyer combines innovative design with a constant focus on our customer’s needs to create successful projects. From the first-ever declining-rate filtration plant designed for Detroit back in 1966, to the world’s largest UV disinfection facility designed for New York City, our engineers and experts are working hard to meet our client’s toughest challenges.

Our designs have encompassed a range of process configurations, from the conventional coagulation/sedimentation/filtration approach to the most advanced high-rate clarification/filtration technologies available. In addition, we are THE experts in dissolved air flotation (DAF). From the first European-based DAF plant in the United States (New Castle, NY) through the world’s largest (290 mgd) DAF plant (in New York City), Hazen and Sawyer has designed more DAF plants than any other firm.

In addition to addressing traditional surface water treatment goals, Hazen and Sawyer has helped providers meet increasingly stringent water quality standards. Projects have included plant upgrades, implementation of alternative disinfection approaches, and application of groundwater treatment processes. Our water treatment process experts are among the best in the business and have presented and/or published hundreds of papers.


Hazen and Sawyer has helped a wide range of clients deliver billions of gallons of high-quality drinking water to their customers, assessing water distribution systems and designing repairs, upgrades and new infrastructure. Study scopes have ranged from relatively simple, one-source water systems, to multiple-source, multi-pressure zone systems with tanks, wells, pumping stations, and interconnections to adjacent communities.

Our engineers are experts in using state-of-the-art computer-aided hydraulic analysis tools, a wide range of pipeline materials and efficient technologies to create robust, reliable distribution systems. And by adding Systems Control and Data Acquisition technology to your system, we can optimize power consumption and demand charges, improve system reliability, and provide greater operating flexibility.


Hazen and Sawyer has performed water system supply and new source evaluations for clients ranging from huge metropolitan areas like New York City to more suburban areas like Wilson, North Carolina. As part of these studies, current and future water demands and supplies are evaluated, and the potential for development of new sources is considered, along with interconnection to neighboring public and private water systems, modifications to existing bulk sale agreements, and redevelopment of existing sources to increase self-reliance. The economic viability of different approaches and possible effects on customer rates are also assessed to determine the best approach.

Our water supply experience also encompasses design and construction management of dams, reservoirs, gatehouses, intakes, channels, wells, storage tanks, pumping stations, and pipelines.