Latest Testing Results

• PFAS Monitoring: Oxnard’s official water quality page confirms that PFAS contaminants have not been detected in any of the city’s water sources based on the most recent comprehensive testing. The Groundwater Desalter’s reverse osmosis technology provides an additional structural safeguard, capable of removing PFAS should they ever be detected. California’s State Water Resources Control Board issued General Order DW-2025-0002-DDW in 2025 requiring initial PFAS monitoring for community water systems — Oxnard continues monitoring in line with evolving state and federal requirements.
• EWG Testing Results: EWG analysis of California State Water Resources Control Board data (2018–2024) found 13 contaminants exceeding health guidelines in Oxnard’s tap water, including arsenic at 344 times the recommended level, disinfection byproducts, heavy metals, and nitrates — though all remain within federal legal limits. The most recent EPA compliance assessment (April–June 2024) confirmed the utility met all federal health-based standards.
• Lead and Copper: Oxnard maintains full compliance with EPA Lead and Copper Rule requirements. Unlike many Eastern U.S. cities, California has very few lead service lines — lead in Oxnard homes primarily arises from pre-1986 plumbing solder rather than service lines. Testing shows levels well below federal action limits, supported by corrosion control treatment and pH optimisation throughout the distribution system.
• Comprehensive Testing Programme: The city conducts hundreds of laboratory tests annually from sample points throughout the distribution system, consistently meeting or exceeding all California Division of Drinking Water and EPA water quality regulations. United Water Conservation District conducts thousands of tests annually for over 180 contaminants in the Oxnard-Hueneme Delivery System. For a national comparison of water quality metrics, see our U.S. water quality checker.

Water Sources — 2026 Supply Blend

• State Water Project (~34%): Imported surface water from Northern California delivered through Calleguas Municipal Water District, treated at either the Metropolitan Water District’s Joseph Jensen Filtration Facility or Calleguas’ Lake Bard Water Filtration Plant before delivery to Oxnard.
• Regional Groundwater (~30%): United Water Conservation District supplies approximately 15,000 acre-feet per year through the Oxnard-Hueneme Pipeline, sourcing water from Santa Clara River diversions and spreading grounds for aquifer recharge. United tests for over 180 constituents annually.
• City Groundwater (~36%): City wells extract water directly from the Oxnard Plain Upper and Lower Aquifer Systems, with a portion treated through the Groundwater Desalter facility before blending at strategic distribution points. The Fox Canyon Groundwater Management Agency oversees sustainable groundwater extraction under California’s SGMA requirements.

Advanced Treatment Technology

• Groundwater Desalter: State-of-the-art reverse osmosis facility operational since 2008, capable of producing up to 7.5 million gallons per day. Removes excess salts, minerals, and potential emerging contaminants including PFAS. The Desalter produces soft water (low hardness) that is then blended with harder groundwater and imported sources to achieve the city’s average of approximately 285 ppm hardness.
• Multi-Source Blending: Strategic blending stations throughout the distribution network optimise water quality, cost, and taste by combining treated water from all three sources. This also allows flexibility to increase Desalter output during drought conditions or supply disruptions.
• Aquifer Storage Recovery Project: The city is expanding recycled water treatment capacity through a $48 million EPA WIFIA-funded project targeting an increase of 14.4 million gallons per day, scheduled for completion in 2027. This will reduce dependence on imported State Water Project supplies and improve drought resilience.

Infrastructure Modernisation

• Groundwater Sustainability: Partnership with Fox Canyon Groundwater Management Agency addresses historic overdraft and the risk of seawater intrusion into the Oxnard Plain aquifer. Sustainable groundwater management plans implemented under SGMA set extraction limits to protect long-term water security for this coastal agricultural region.
• Seawater Intrusion Management: United Water Conservation District is planning construction of iron and manganese treatment facilities for deep wells supplying the Oxnard-Hueneme Pipeline, improving operational flexibility and drought resilience in the regional supply network.
• Distribution System Improvements: Ongoing upgrades to the water distribution network including real-time monitoring systems and infrastructure replacements to maintain water quality from treatment plant to tap, particularly as the 2027 recycled water expansion progresses.

Customer Protection Initiatives

Oxnard Water Division provides extensive customer support through annual Consumer Confidence Reports, conservation partnership programmes with Calleguas and Metropolitan Water Districts, and proactive monitoring for emerging contaminants. The city’s official guidance explicitly states that PFAS have not been detected in any sources and that the Desalter’s reverse osmosis technology stands ready to address them if needed. Hard water information is clearly communicated to residents — at 285 ppm average, white spotting on glassware is common but poses no health risk. Residents with taste or quality concerns can contact the Water Service Center directly or review contaminant data in the annual CCR at oxnard.gov. For filter options matched to Oxnard’s contaminant profile — particularly arsenic and disinfection byproducts — see our water filter solutions guide. Stay updated on local water quality advisories via our water alert news feed.