Water management in LA County today reflects a historically siloed view that failed to recognize the interconnectedness of all water, including groundwater, surface water, rainwater, and wastewater. This approach has led to a complex, disjointed system that is not well-suited to adapting to the needs of a rapidly growing region and changing climate. Building on the successful passage of the Safe Clean Water Program (Measure W), which promises to support an integrated and holistic approach to stormwater management, the region must invest in a 21st-century water system that prioritizes multi-benefit management strategies that restore and mimic natural processes and cycles.

Percent Local Water

  • Just under 1.5 million acre-feet of water was supplied to LA County in 2017. This is close to half a million acre-feet less than in the year 2000.
  • In 2017, approximately 59% of the water used in LA County was sourced from outside the region. This breaks down as: 33% from MWD service water and 26% from the LAA. While the percentage of water sourced from outside the region was similar in 2016 and 2017 (55% and 59%, respectively), the percentage of water provided through the LAA increased by from 6% in 2016 to 26% in 2017, while the percentage from MWD imports decreased from 49% in 2016 to 33% in 2017.
  • Groundwater resources provided 32% of total Countywide demand, and local recycled water contributed 9%. Together, these sources provided 41% of the total supply. However, because the MWD category “groundwater” includes both runoff from local watersheds as well as an unspecified amount of imported water used for groundwater replenishment, it is not currently possible to accurately answer the question of how much of LA County’s supply is truly local.

Per Capita Water Consumption

  • Between 2000 and 2017, there was a decrease of over 27% in total countywide water demand.
  • More recently, there was a 12% decrease in total countywide demand between 2013 and 2017, from 163 to 143 gallons per capita per day (GPCD).
  • Both potable consumptive demand and total MI demand increased between 2016 and 2017, by 3-4%; however, total demand remained below the 2016 level.

Primary MCL Violations by Public Water Systems in LA County (2012 - 2017)

  • In 2017, seven public water systems in LA County, serving a total of over 60,000 residents, had a combined total of 10 violations of primary MCLs.
  • Overall, 50 water systems had violations of at least one MCL from 2012 through 2017.
  • There is no clear trend in the number of violations and in the number of systems in violation over the six-year review period.
  • All violations for the last 6 years were for arsenic, nitrate, or total coliform bacteria, with the exception of one TTHM (Total Trihalomethane) violation in 2017.
Annual Compliance Reports from the SWRCB do not contain information on secondary MCL violations – this is a significant data gap that needs to be filled.

Number of Public Water Systems with Primary MCL Violations in LA County (2012 - 2017)

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Population Impacted by Primary MCL Violations in LA County (2012 - 2017)

The population served by systems with MCL violations was significantly higher in 2012 (74,931 people) and 2017 (61,641 people) than for the intervening years (when it ranged between 3,850 and 2,909), due to larger water systems having violations in those years only. In 2012, the City of Beverly Hills and the El Monte City Water Department had violations; in 2017, the City of La Verne Water Division and California State Polytechnic University – Pomona had violations.

Beach Report Card Scores

  • Summer 2017 dry weather water quality in LA County was excellent with 97% A or B grades and zero F grades, better than the average over the last 5 years.
  • Winter dry weather grades for the most recent year were slightly better than the average over the previous five years. 


  • Wet weather water quality continues to be an area of concern, with only 60% A or B grades, and with 26% receiving F grades in 2017-2018. However, this is an improvement over 2016-2017, and better than the average over the previous 5 years.
  • There has been an overall upward trend from 78% to 91%, in the percentage of beaches with summer dry A grades in the past five years, with a corresponding reduction in the number of B and C grades over that period. Less than 5% of beaches received F’s each year since 2013, with the last two years receiving no F grades at all. 

Number and Volume of Sewage Spills to Water

  • In 2017 there were 302 reported sewage spills, of which 92 (31%) reached waterbodies. This represented almost 600,000 gallons of sewage spilled in total, with approximately 380,000 gallons (65%) of that volume reaching waterbodies.
  • Within the period reviewed, 2013 had the highest total number of spills that reached a waterbody; however, the number of major spills has progressively increased from 4 in 2013 to 12 in 2017.



  • The volume of sewage reaching waterbodies in 2017 was less than 2015 and 2016, but higher than 2013 and 2014. 
  • The peak in volume of sewage spills reaching water in 2016 was primarily due to one very large spill of 2.6 million gallons, of which 1.7 million gallons entered storm drains leading to the Los Angeles River