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Joseph Jensen Treatment Plant

The Joseph Jensen Treatment Plant in Granada Hills is one of five water treatment plants in the Metropolitan Water District system.

Jensen sits high in the foothills of the Santa Susana Mountains at the northwest end of the San Fernando Valley.  Its 1,290-foot elevation enables the plant to distribute to points within the valley, to Ventura County and south to West Los Angeles, Santa Monica and the Palos Verdes Peninsula.

From Mountain High...

The water filtered through this plant originates in northern California's mountains, rivers and streams, and flows through the Sacramento-San Joaquin Delta before entering the State Water Project's 444-mile California Aqueduct.

Jensen is the only facility that does not treat water that comes from the Colorado River and through Metropolitan's 242-mile Colorado River Aqueduct.

Thanks to a multimillion-dollar expansion project,.  Jensen is believed to  be the largest treatment plant west of the Mississippi River, delivering up to 750 million gallons per day.  This means the plant cleans enough water to fill the Rose Bowl in less than three hours.  Jensen was among the first of Metropolitan’s treatment plants to convert to ozone treatment, having finished the process in 2005.  The 125-acre site has room for one more treatment module.

Automated systems regulate water levels and pressure.  These precise monitoring and surveillance capabilities allow plant operators to anticipate and meet demands, and to respond rapidly to emergency situations.

...To Your Kitchen Faucet

Looking at the treatment plants web of pipes, pumps and sophisticated electronic gadgetry, filtration appears to be complicated.  Conventional filtration, however, is surprisingly simple and effective.

Items used are similar to those found in any home, garden or garage.  Upstream grates and screens catch large debris and plants.  At the treatment plant, coal and sand--used as filter media--remove any particles left in the water.  Then, ozone, and/or chlorine and ammonia are used as disinfectants.

Conventional filtration involves what is known as coagulation, where aluminum sulfate and other chemical additives cling to particle matter in the water.  These compounds adhere to each other, forming large particles called floc.  Once the water and floc enter large sedimentation basins, the floc settles to the bottom.

From the basins, water filters through the coal and sand layers, and then is disinfected to kill the few remaining microorganisms.  MWD water meets or surpasses all state and federal water quality standards.

The Jensen Legend

Joseph Jensen became the board's fourth chairman in 1949 and served 25 years until his death in 1974.  He was the longest serving chairman in Metropolitan history.  During his tenure, Jensen saw the district evolve from 16 member agencies serving some 3.5 million people to one that encompassed 26 member agencies, and more than 10 million residents. (The district today serves 19 million people.) He guided the board through the politically sensitive planning of the State Water Project, conflicts over water rights on the Colorado River, and a major expansion of the district's distribution system. A man relatively small in stature, Jensen was noted as being an "awesome figure for his size…tough, thoughtful and dedicated."

Jensen's legacy of prudent expansion continues.  More than 1,800 people work at Metropolitan, and many of them work exclusively on maintaining and upgrading what has become one of the world's largest water distribution systems.

photo of Jensen Treatment Plant headquarters building
Joseph Jensen Treatment Plant
13100 Balboa Blvd.
Granada Hills, CA 91344
photo of Jensen Treatment Plant headquarters building

Page updated: August 3, 2011