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History and Background

Treatment of wastewater is a relatively modern practice. It was not until the late 19th century that large cities realized that they had to reduce the amount of pollutants they were discharging into the environment. In 1885, the City began its first municipal sewer service, which was only along the lower portion of Fifth and Sixth avenues in downtown with the raw effluent discharged directly into San Diego Bay. As the City grew, raw sewage was not only discharged into the bay, but also directly into the Pacific Ocean through 22 sewage outfalls.

In 1943, a 14 million-gallon-per-day treatment plant went into operation on East Harbor Drive just south of 32nd Street. The U.S. Navy built the treatment plant to reduce the health risks to sailors on ships in San Diego Bay. Although the plant was enlarged in 1950 to handle 40 million gallons of wastewater per day, San Diego's growing population soon overwhelmed the plant's capabilities.

In 1963, the City completed the Point Loma Wastewater Treatment Plant, Point Loma Ocean Outfall, and the Municipal Wastewater Collection System. The Point Loma plant remains the mainstay of the wastewater system, processing approximately 160 million gallons a day of wastewater generated by 2.2 million residents in a 450 square mile service area. The facility has a treatment capacity of 240 million gallons per day.

In the late 1980s, the City and the U.S. Environmental Protection Agency (EPA) were involved in a legal dispute over the requirement to treat sewage at the Point Loma Wastewater Treatment Plant to secondary standards. The City prevailed, saving ratepayers an estimated $3 billion. As a result of the ensuing court order, the City embarked upon a $1.4 billion Capital Improvement Program. The Point Loma Wastewater Treatment Plant underwent expansion and rehabilitation, and the Point Loma Ocean Outfall was extended. The City's first new treatment plant under the program, designed to turn wastewater into a recyclable asset, was the North City Water Reclamation Plant. It went online in 1997. In 1998, the Metro Biosolids Center, which processes the solid waste from wastewater, started operations. The final major construction element of the Capital Improvement Program, the South Bay Water Reclamation Plant, opened in 2002.

Since the Point Loma Wastewater Treatment Plant's advanced primary process had proved so successful in maintaining a healthy ocean environment, the requirement to perform secondary treatment on wastewater before ocean discharge was waived by the passage of the Ocean Pollution Reduction Act in 1994. With the full support of the EPA, the City received a renewal of this modified permit in 2002 and again in 2010.

In 2010, the Environmental Monitoring & Technical Services Laboratory opened at Liberty Station to improve its support of the Ocean Monitoring Program.

Metropolitan Sewerage System

The Metropolitan Sewerage System treats the wastewater from the City of San Diego and 15 other cities and districts (called participating agencies) from a 450 square mile area with a population of over 2.2 million. An average of 180 million gallons of wastewater is treated every day of the year.

The participating agencies are the cities of Chula Vista, Coronado, Del Mar, El Cajon, Imperial Beach, La Mesa, National City, Poway, the Lemon Grove Sanitation District, the Otay Water District, the Padre Dam Municipal Water District, the County of San Diego (including Lakeside/Alpine, Spring Valley, Winter Gardens, and East Otay Mesa).

Municipal Wastewater Collection System

The Public Utilities Department's Wastewater Collection Division is responsible for the collection and conveyance of wastewater from residences and businesses in the City of San Diego, serving a 330 square-mile area with a population of 1.3 million people.

  • Miles of City sewer lines: 2,894+
  • Number of City connections to sewer lines: 250,000+
  • Municipal Pump Stations: 84
  • City manholes: 55,000+


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