Pure Water San Diego

Water Transmission

Large diameter cement mortar coated steel pipe on a road awaiting install


75,447 LF of 48” and 36,254 LF of 30” Spiralweld Steel Pipe with Cement Mortar Lining and Cement Mortar Coating with Polyethylene Tape Wrap




City of San Diego


HDR Engineering; AECOM


W.A. Rasic Construction; Sukut Construction

Pure Water San Diego is a phased, multi-year program that will provide nearly half of the City of San Diego’s water supply locally by the end of 2035. This project uses proven water purification technology to clean recycled water to produce safe, high-quality drinking water. Currently, 85% of San Diego’s water supply is imported, and rates for imported water have more than tripled over the last two decades. Meanwhile, only 8% of the City’s wastewater is being recycled. The Pure Water Program offers a cost-effective investment for San Diego’s water needs and will provide a reliable, sustainable, drought-resistant water supply for the City’s growing communities. To support Phase 1 of the program, Northwest Pipe Company (NWP) is supplying over 21 miles of 30- and 48-inch engineered steel pipeline, which will be used to convey wastewater and purified water across the Pure Water network.

Phase 1 of Pure Water San Diego includes 10 projects that add and improve infrastructure, including pump stations, purification facilities, and pipelines. NWP is providing steel pipe for two critical components of Phase 1: the North City Pure Water Pipeline project and the Morena Pipelines Southern and Middle Alignment project.

The North City Pure Water Pipeline project utilizes 39,480 LF of 48-inch steel pipe manufactured by NWP to complete the majority of its 8.4-mile alignment. Once in service, it will transport 30 million gallons of purified water per day from the North City Pure Water Facility to the Miramar Reservoir, where it will be stored before being purified once more for use. Long Beach-based W.A. Rasic Construction is the installation contractor for this segment.

For the Morena Southern and Middle Alignment project, NWP manufactured over 13.6 miles of engineered steel pipe, which is being installed by contractor Sukut Construction. The Southern Alignment starts at the newly constructed Morena Pump Station and includes parallel 30- and 48-inch pipelines. The 48-inch main carries wastewater north to the North City purification facility. The 30-inch main is a brine line that conveys water purification byproduct south to the Point Loma Wastewater Treatment Plant. The Middle Alignment connects the Southern and Northern Alignments.

The engineered steel pipe NWP supplied for Phase 1 of the Pure Water Program was manufactured at our Southern California facility in Adelanto. Over 8,080 tons of steel was used to produce more than 111,700 LF of pipe for these two projects. The pipe is made with cement mortar lining and tape wrap coating with a cement mortar overcoat.

With the Pure Water Program, San Diego joins many other innovative agencies creating safe and resilient water supplies through reclamation and purification. The program scales the proven purification technology already in use at the City’s Pure Water Demonstration Facility, which since 2011 has been producing one million gallons of purified drinking water per day. Pure Water’s state-of-the-art purification process utilizes a multi-barrier approach of ozonation, biological activated carbon, membrane filtration, reverse osmosis, and UV/Advanced oxidation to produce high-quality, clean drinking water that meets all federal and state standards.

The multi-phased Pure Water San Diego represents the largest integrated infrastructure program in the City’s history. Phase I is expected to be completed in 2025, producing 30 million gallons of purified water per day. Phase 2 will increase the program’s output by 53 million gallons per day, for a total of 83 million gallons of purified water per day by 2035.

Learn More About the Project:  purewatersd.org