Los Angeles – California
Los Angeles, America’s second-largest city, manages a complex water system serving over 4 million residents across 600 square miles. The Los Angeles Department of Water and Power (LADWP) operates the nation’s largest municipal utility, delivering roughly 160 billion gallons of water annually through a network of reservoirs, treatment facilities, and 7,200 miles of pipes.
The city sources its water from three main supplies: the Los Angeles Aqueduct (delivering water from the Eastern Sierra Nevada), purchased water from the Metropolitan Water District (Colorado River and Northern California), and local groundwater. Following severe drought conditions over the past decade, LA has increased focus on water conservation, recycling, and stormwater capture to build a more sustainable and resilient water system.
Los Angeles Water Quality: Current Status (2024-2025)
Latest Testing Results
- Lead Levels: The most recent testing period (January-December 2023) showed 90th percentile lead levels of 4.0 parts per billion (ppb), well below the EPA action level of 15 ppb.
- Testing Scope: Over 200 sample sites are regularly monitored throughout the city’s distribution system, with additional targeted sampling in older neighborhoods with potential lead service connections.
- Compliance Status: Los Angeles water meets or exceeds all federal and state drinking water standards. The LADWP’s water treatment processes help ensure high-quality drinking water throughout the distribution system.
Infrastructure Progress
- Lead Service Line Inventory: LADWP has completed a comprehensive inventory of service lines under the Lead and Copper Rule Revisions, identifying fewer than 2,000 lead service lines or lines of unknown material that are scheduled for replacement by 2028.
- Water Main Replacement: The city is currently replacing approximately 300,000 feet of aging water mains annually as part of its Water Infrastructure Program, prioritizing pipes installed before 1940.
- Reservoir Improvements: All open reservoirs now use UV or floating covers, underground storage, or advanced treatment facilities to comply with federal regulations and protect drinking water quality.
Water Source and Treatment
- Current Water Sources: Los Angeles sources approximately 40% of its water from the LA Aqueduct, 41% from the Metropolitan Water District, and 19% from local groundwater, with percentages varying based on rainfall and drought conditions.
- Treatment Process: Water from the LA Aqueduct is treated at the Los Angeles Aqueduct Filtration Plant, which can process up to 600 million gallons per day using state-of-the-art ozonation, filtration, and chloramination processes.
- Groundwater Protection: Enhanced remediation efforts are underway in the San Fernando Valley groundwater basin to address historical industrial contamination, with new treatment facilities scheduled for completion in 2025-2026.
Future Water Quality Initiatives
- Operation NEXT: A major initiative to locally source up to 70% of LA’s water by 2035 through expanded water recycling and groundwater replenishment at the Hyperion Water Reclamation Plant.
- Advanced Testing: LADWP is incorporating emerging contaminant monitoring for PFAS (per- and polyfluoroalkyl substances) and microplastics, staying ahead of potential regulatory changes.
- Climate Resilience: Investments in diverse water sources and infrastructure protection to mitigate impacts from climate change, including droughts, wildfires, and extreme weather events.
Drought Response
Despite recent increased rainfall, Los Angeles remains under Phase 3 water conservation rules that limit outdoor watering to three days per week. The focus on water efficiency has helped LA maintain among the lowest per capita water usage of any major U.S. city, with average daily use at 111 gallons per person.
Recommendations for Los Angeles Residents
Consider Using Filters
If you live in an older home (pre-1986), consider using NSF-certified filters for drinking water. Look for filters certified to remove lead (Standard 53) and other contaminants of concern.
Test Your Water
Los Angeles residents can request water quality testing by calling LADWP’s Water Quality Hotline at (213) 367-3182 or emailing waterquality@ladwp.com to arrange for testing.
Update Plumbing Fixtures
If you live in a home built before 1986, consider replacing older faucets and fixtures with modern “lead-free” alternatives that comply with current standards.
Flush Your Pipes
If water hasn’t been used for six hours or more, run cold water for 30-60 seconds before using. Always use cold water for drinking and cooking, as hot water may contain higher levels of metals from your plumbing.
Conserve Water
Follow current water conservation rules and check LADWP.com for updates on restrictions. Install water-efficient fixtures and appliances to reduce usage and take advantage of available rebates.
Frequently Asked Questions
Is Los Angeles tap water safe to drink?
Yes, Los Angeles tap water meets all federal and state standards for safety and is regularly tested for over 200 constituents. LADWP conducts more than 35,000 water quality tests annually throughout its distribution system. The water undergoes rigorous treatment processes including filtration, disinfection, and corrosion control before reaching your tap. However, if you live in an older building with older plumbing, you may want to consider using a certified water filter as an extra precaution.
Why does my water sometimes taste or smell different?
Occasional changes in taste or odor can occur for several reasons. Chlorine, which is added as a disinfectant, may be more noticeable at certain times. Seasonal changes in source water, temporary increases in disinfectant levels during system maintenance, or algae blooms in reservoirs can affect taste and odor without compromising safety. If your water consistently has an unusual taste or smell, contact LADWP at (800) 342-5397 to report it. You can improve taste by refrigerating water in an open container or using a certified filter.
Are there lead service lines in Los Angeles?
Los Angeles has relatively few lead service lines compared to older cities in the eastern United States. LADWP’s recent inventory identified fewer than 2,000 service lines that are made of lead or of unknown material that could contain lead. The department is actively replacing these lines and expects to complete this work by 2028, ahead of federal requirements. Most lead exposure from water in LA comes from older household plumbing rather than from service lines. If you live in a home built before 1986, running your water before use and considering certified filters can reduce potential lead exposure.
What is being done about PFAS in Los Angeles water?
PFAS (per- and polyfluoroalkyl substances) are emerging contaminants that have been detected at low levels in some Los Angeles groundwater sources. LADWP conducts regular testing for these compounds and has been proactive in addressing them. The utility has temporarily taken some groundwater wells offline when PFAS levels exceeded California’s notification levels and is installing specialized treatment systems at affected groundwater facilities. The primary drinking water from the Los Angeles Aqueduct and Metropolitan Water District has very low to non-detectable levels of PFAS. LADWP follows all state guidelines and is preparing for upcoming federal regulations.
Contaminants of Concern
PFAS Compounds
Source: Industrial chemicals that have contaminated some groundwater sources, particularly in the San Fernando Valley
Health Effects: Potential developmental effects to fetuses, cancer, liver damage, immune system effects, thyroid disruption
Current Status: Most detected levels below California notification levels; affected wells being treated or taken offline
Lead
Source: Primarily from older household plumbing fixtures and solder (pre-1986); very few lead service lines in Los Angeles
Health Effects: Developmental delays in children, kidney problems, high blood pressure, reproductive issues in adults
Current Levels: 90th percentile value of 4.0 ppb, well below the EPA action level of 15 ppb EPA Limit: Action level 15 ppb, but no level of lead is considered safe
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