Detailed location data (address and coordinates) sourced from reports from the California Integrated Water Quality System (CIWQS) sanitary sewer overflow (SSO) database and were generated using the Interactive SSO Reports tool from the State Water Resources Control Board (SWRCB) Sanitary Sewer Overflow Reduction Program. Data on Category 1, 2 and 3 SSOs in LA County for the years 2013 to 2017 was used.

Summary data sourced from reports from the California Integrated Water Quality System (CIWQS) sanitary sewer overflow (SSO) database and were generated using the Interactive SSO Reports tool from the State Water Resources Control Board (SWRCB) Sanitary Sewer Overflow Reduction Program. Data on Category 1, 2 and 3 SSOs in LA County for the years 2013 to 2017 was used. The number and volume of spills was analyzed. For some spills, only a portion of the spill volume may have reached a waterbody. Spills were categorized as small (<1,000 gallons), minor (between 1,000 and 10,000 gallons), or major (>10,000 gallons).

See "Number and Volume of Sewage Spills to Water (2013-2017) Detailed" for more detailed data.

This data is summary data. Please see Exceedances of Primary Maximum Contaminant Levels (MCLs) by Public Drinking Water Systems (2012-2017) for more detail.
Population data from LA County Department of Finance

Data includes violations of maximum contaminant levels (MCLs) for primary drinking water contaminants in public water systems in LA County from 2012 to 2017, as listed in the Annual Compliance Reports published by the SWRCB. For 2012 and 2013, this was published by the DPH. Data on secondary MCL violations is not available. In some cases, the same violation is listed multiple times on the ACR due to responsive actions being reported via separate listings; the number of violations were identified using the unique violation identification number and compliance period dates to avoid duplicative counting.

Grades, beach location and analysis from Heal the Bay's Beach Report Card was used (2013-2018), which uses a 12-month grading period from April to March. Seasonal patterns of the most recent year’s grades (2017-2018), as well as trends over the last five years were used. As defined in Assembly Bill 411 in California, the summer dry grading period is from April through October. The winter dry weather grading period is from November through March. The year-round wet weather conditions are graded from April through March. Values may not add up to exactly 100% due to rounding.

Data includes countywide water consumption using data from the Metropolitan Water District (MWD) for LA County (provided through data request). The three categories of water use are: “Total Municipal and Industrial (MI) Demand”; “Potable Consumptive Demand” which is MI Demand minus recycled water – this is the value used to calculate gallons per capita per day (GPCD) water use for compliance with SBX7-7; and “Total Demand” which includes MI, agricultural, seawater barrier and groundwater replenishment.
Data for 2000-2017 was reviewed, with particular interest in changes since 2013, in response to the Governor’s January 2014 drought declaration.
MWD member agencies include: Central Basin Municipal Water District, City of Beverly Hills, City of Burbank, City of Compton, City of Glendale, City of Long Beach, City of Los Angeles, City of Pasadena, City of San Fernando, City of San Marino, City of Santa Monica, City of Torrance, Foothill Municipal Water District, Las Virgenes Municipal Water District, Three Valleys Municipal Water District, Upper San Gabriel Valley Municipal Water District, West Basin Municipal Water District,

Water Use Type is: MI=Municipal and Industrial; AG=Agricultural; SW=Seawater Barrier; and GW=Groundwater Replenishment

Water Use Grouping includes:
Total MI Demand - Total consumptive demand or water used to meet municipal and industrial demands.
Potable Consumptive Demand (20x2020) - Demand used for calculating per capita water use for complying with SB x7-7 that excludes recycled water use. Recycled water is a part of water-use efficiency.
Total Demand - Total water use that includes municipal and industrial, agricultural, seawater barrier, and groundwater replenishment.

For per capital, population is based on the Department of Finance's annual estimates, extrapolated to each member agency.

Data includes source and amount of water across LA County. Water is supplied across LA County by approximately 100 different suppliers, many of which source their water through Metropolitan Water District (MWD), the regional wholesale water agency. MWD imports water from the Bay-Delta via the State Water Project (SWP) and from the Colorado River via the Colorado River Aqueduct (CRA). Since it was infeasible to compile data from all suppliers, MWD data for LA County (provided through a data request) was used to understand water sources for the entire county.
MWD identifies four main sources for LA County’s water: imported water, local groundwater and surface water, the Los Angeles Aqueduct (LAA, which supplies the City of Los Angeles only), and local recycled water.
For evaluation purposes, LAA supplies was considered to be imported water.
How much water came from each source was examined.
The most recent (2017) values to historical data (2000-2017) was compared.
Note: Although City of LA counts conservation as part of their local water supply, this definition was not included in this analysis.