Fresno – California
Fresno’s Department of Public Utilities (DPU) Water Division serves over 540,000 residents, making it one of the largest exclusively groundwater-dependent systems in the United States. The utility manages approximately 1,800 miles of water mains, 260 groundwater wells, and delivers an average of 125 million gallons daily to this growing Central Valley community.
Unlike most major California cities, Fresno relies almost entirely on groundwater pumped from the Kings Subbasin of the San Joaquin Valley Groundwater Basin for its municipal water supply. This unprecedented dependence on groundwater presents unique challenges as the region faces long-term aquifer depletion. Despite receiving only 11 inches of average annual rainfall, Fresno has implemented innovative water management strategies including groundwater recharge facilities, water conservation programs, and a recent transition to partial surface water treatment. The city’s “Recharge Fresno” program represents a $600 million investment to diversify water sources, improve infrastructure, and ensure sustainable water supplies for this agricultural hub in California’s drought-prone Central Valley.
Fresno 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 2.5 parts per billion (ppb), well below the EPA action level of 15 ppb, reflecting Fresno’s newer infrastructure and effective treatment protocols.
- Testing Scope: Fresno conducts over 50,000 water quality tests annually, monitoring for more than 100 regulated contaminants and additional unregulated substances through its comprehensive sampling program.
- Compliance Status: Fresno’s water meets all federal and state drinking water standards, maintaining full compliance with EPA and California State Water Resources Control Board Division of Drinking Water regulations.
Groundwater Supply
- San Joaquin Valley Aquifer: Primary source (approximately 80% of supply) with water drawn from 260 active wells across the city, providing naturally filtered water with consistent quality.
- Surface Water Treatment: The newer Northeast Surface Water Treatment Facility now provides approximately 20% of Fresno’s water supply, treating water from the Kings River and Millerton Lake.
- Aquifer Protection: Comprehensive groundwater management strategy including artificial recharge basins, injection wells, and participation in the North Kings Groundwater Sustainability Agency.
Treatment Excellence
- Groundwater Treatment: Selective wellhead treatment including granular activated carbon filtration and ion exchange systems at wells with identified contaminants of concern.
- Surface Water Treatment: State-of-the-art T.L. Swiridoff Northeast Surface Water Treatment Facility utilizing membrane filtration, ultraviolet disinfection, and advanced oxidation processes.
- Disinfection: Chlorination of groundwater at wellheads and advanced disinfection at the surface water treatment plant, with continuous monitoring to maintain effective pathogen control while minimizing disinfection byproducts.
Infrastructure Transformation
- Recharge Fresno Program: $600 million investment in water infrastructure including surface water treatment, transmission pipelines, and groundwater recharge facilities.
- Southeast Surface Water Treatment Plant: New facility under construction to further reduce groundwater dependence and improve water quality in southern Fresno neighborhoods.
- Advanced Metering Infrastructure: Citywide installation of smart meters with leak detection capabilities and real-time consumption monitoring to improve conservation and system management.
Drought Resilience Planning
Fresno has developed a forward-looking water sustainability strategy addressing the unique challenges of California’s drought cycles and groundwater depletion. The city’s “Water Resource Management Plan” and “Drought Contingency Plan” include measures to increase groundwater recharge through purpose-built basins that capture stormwater and flood releases from local rivers. Fresno’s “Big Dry Creek Groundwater Recharge Project” and “Leaky Acres Recharge Facility” collectively can return billions of gallons of water to the aquifer annually. The city has implemented one of California’s most aggressive water conservation programs, reducing per capita water use by over 30% since 2000 through progressive water rates, landscape conversion programs, and efficiency requirements. Fresno’s water planning specifically addresses SGMA (Sustainable Groundwater Management Act) compliance, with infrastructure designed to achieve groundwater sustainability by 2040 while maintaining reliable service during extended drought periods that are becoming increasingly common in California’s Central Valley.
Recommendations for Fresno Residents
Request Water Testing
Fresno residents can request free water quality testing by calling (559) 621-5300. This service is particularly recommended for households in areas with known 1,2,3-TCP or nitrate concerns, or those with older plumbing systems installed before 1986.
Consider Filtration
While Fresno water meets all health standards, residents concerned about taste or hardness may benefit from NSF-certified filters. For areas with elevated nitrate levels, consider reverse osmosis systems certified under NSF/ANSI Standard 58.
Implement Water Conservation
Take advantage of Fresno’s water conservation programs, including rebates up to $1,000 for water-efficient landscaping and up to $100 for high-efficiency toilets and smart controllers. Visit www.fresno.gov/waterconservation for program details.
Follow Watering Schedule
Adhere to Fresno’s outdoor watering schedule based on your address. Year-round water regulations limit watering to specific days and prohibit water waste. Download the Fresno H2O app for reminders and to report water waste.
Report Water Issues
Report water main breaks, water quality concerns, or pressure problems immediately through the FresGO app or by calling (559) 621-CITY. Early reporting helps DPU respond quickly and prevent potential contamination.
Frequently Asked Questions
Is Fresno’s tap water safe to drink?
Yes, Fresno’s tap water is safe to drink and meets all federal and state quality standards. The water undergoes regular testing and treatment to ensure compliance with health-based regulations established by the EPA and the California State Water Resources Control Board.
Fresno’s water quality has significantly improved with the addition of the Northeast Surface Water Treatment Facility, which now provides about 20% of the city’s supply with enhanced treatment. The remaining groundwater supply is tested at each well and treated as needed to address any contaminants.
Some residents may notice that Fresno water is relatively “hard” due to naturally occurring minerals in the groundwater. While this affects taste and can cause scaling on fixtures, it poses no health risk. If you have specific concerns about your water quality, the City of Fresno offers free water testing services.
What is 1,2,3-TCP and how is Fresno addressing it?
1,2,3-Trichloropropane (TCP) is a synthetic chemical formerly used in soil fumigants that has been detected in some Fresno groundwater wells. This contaminant is a concern because it’s classified as a likely carcinogen. Fresno is addressing 1,2,3-TCP through several strategies:
• Granular Activated Carbon treatment: Installation of specialized filtration systems at affected wells to remove TCP
• Surface water integration: Increasing reliance on surface water to reduce dependency on affected groundwater
• Enhanced monitoring: Regular testing of all wells for TCP at levels below the state Maximum Contaminant Level of 5 parts per trillion
• Legal action: Fresno has secured settlements from chemical manufacturers to fund treatment systems
The city’s treatment approach has successfully reduced TCP levels to comply with California’s stringent standards, which are among the strictest in the nation for this contaminant.
How is Fresno addressing groundwater sustainability?
Fresno is implementing a comprehensive approach to groundwater sustainability in compliance with California’s Sustainable Groundwater Management Act (SGMA):
• Surface Water Integration: The Northeast Surface Water Treatment Facility and planned Southeast Surface Water Treatment Plant reduce groundwater pumping by utilizing Kings River and Millerton Lake water rights
• Recharge Infrastructure: Operation of over 20 groundwater recharge basins capturing stormwater and flood releases, with capacity to recharge billions of gallons annually
• Recycled Water Program: Development of non-potable water distribution for landscape irrigation and industrial uses
• Conservation Programs: Tiered water rates, rebates for efficient fixtures, and drought-resistant landscaping incentives
• Regional Collaboration: Active participation in the North Kings Groundwater Sustainability Agency to coordinate aquifer management
These efforts have already helped stabilize declining groundwater levels in parts of Fresno and will continue to be expanded to achieve long-term sustainability by 2040 as required by state law.
Why does water quality vary in different parts of Fresno?
Water quality can vary across Fresno neighborhoods due to several factors:
• Geographic distribution of contaminants: Natural and man-made contaminants are not uniformly distributed in the aquifer
• Well depth and construction: Different wells draw from various depths and aquifer zones with distinct water quality characteristics
• Infrastructure age: Older neighborhoods may have aging pipes that can affect water quality at the tap
• Surface water integration: Northeast Fresno now receives a blend of treated surface water and groundwater, while other areas remain on groundwater only
• Targeted treatment systems: Some wells have specialized treatment for specific contaminants while others may not require the same level of treatment
The city’s long-term plan is to expand surface water treatment to additional areas, particularly in south Fresno, and to standardize water quality throughout the distribution system. The Southeast Surface Water Treatment Plant currently under construction will help address some of these disparities when completed.
Contaminants of Concern
1,2,3-Trichloropropane (TCP)
Source: Agricultural soil fumigants used historically in the Central Valley, primarily from the 1950s through the 1980s, which has leached into groundwater
Health Effects: Classified as a likely human carcinogen based on laboratory studies; long-term exposure to elevated levels may increase cancer risk
Current Status: Detected in approximately 40% of Fresno’s wells, but treated with granular activated carbon where present; all distributed water meets California’s MCL of 5 parts per trillion
Nitrate
Source: Agricultural fertilizers, animal waste, septic systems, and natural soil processes; more prevalent in shallower wells in parts of south and west Fresno
Health Effects: High nitrate levels can interfere with oxygen transport in the bloodstream, particularly dangerous for infants and pregnant women; can cause “blue baby syndrome” (methemoglobinemia)
Current Levels: Varies by well, with some showing elevated levels requiring blending or treatment EPA/State Limit: 10 milligrams per liter (mg/L) as nitrogen; all distributed water in Fresno meets this standard
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