Where Does LA's Tap Water Come From?

In 2009, 200 billion gallons of water used in Los Angeles met or surpassed all health based drinking water standards set by the U.S. Environmental Protection Agency and the California Department of Public Health Drinking Water Program. The Los Angeles Department of Water and Power took over 25,000 water samples and completed 240,000 water quality tests- which is more than required. According to their 2009 Annual Water Quality Report, which was recently released, there are thirteen steps which your water goes through before it comes out your tap. 

The Journey of a Drop of Water


1. Beginning of L.A. Aqueducts

• Water is collected from creeks in the Owens Valley
• Carried by gravity downstream

2. Making Hydro-power

• Creates electricity as it passes through the San Francisquito Power Plant

3. End of L.A. Aqueducts

• Water flows over steps to release energy
• Water added from State Water Project and Colorado River Aqueduct

4. Screening

• Passes through an inlet for filtration
• Large debris and algae are removed by screens

5. Ozonation

• Ozone gas is added to water, which acts as an disinfectant

6. Filtration

• Water passes through 60 inches of filters
• Anthracite Coal Filters remove particles as small as microns

7. Filtrated Water to Pump Stations

• Water sits, waiting to be pumped

8. Chlorination Station

• Regulated chlorine amounts are added to water to protect from bacteria and pathogens as it travels through distribution systems

9. North Hollywood Sump and Pump Station

• More water is added from the San Fernando Valley Wells

10. River Supply Conduit

• Travels through the city to the Ivanhoe Reservoir, near Silver Lake
• Transported in 78 inch pipes

11. Water Storage

• Protected by shade balls to ensure water quality

12. Local Pump Station

• More chlorine is added if water is going east of the reservoir

13. L.A. Neighborhood

• Travels through locals pipes and then the interior plumbing to your faucet, shower head, washer, toilet, or other water using device

According the L.A. Department of Water and Power the water is safe for drinking by E.P.A. standard but just to be safe use a Brita Filter or Pur Tap. Both are inexpensive and cost effective compared to bottled water. Cheers!


Please check back for a complete list by area and city for where your water originates. 


All information taken from the Los Angeles Department of Water and Power "2009 Annual Water Quality Report" please visit www.ladwp.com, www.cdph.ca.gov, or www.epa.gov for more information.