The Central San Joaquin region (S2J2 Region) has a population of about 1.78 million with over 60 percent the census tracts designated as “disinvested,”^[1] compared to a statewide 29 percent of census tracts. The average household income in the S2J2 region is more than 30 percent lower than the California average and 44 percent lower in “disinvested” areas. Nearly 1 in 5 people live below the poverty line in the S2J2 region, compared to 1 in 8 in the rest of the state. In disinvested areas the poverty rate increases to 1 in 4 (Urban Institute, 2023). In the San Joaquin Valley, many households and communities experience dry wells, drinking water contamination, and unaffordable drinking water costs. When experienced first-hand, these drinking water crises lead to physical, emotional, and financial hardship for families. Declining water levels, groundwater contamination, and insufficient and incomplete drinking water infrastructure have left tens of thousands of Valley residents without access to safe, affordable, and reliable drinking water in their homes.

Estimates indicate that almost 93 of the 353 public drinking water systems in the S2J2 region violate safe drinking water standards and have pending enforcement actions due to high levels of contaminants. Drinking water contamination disproportionately impacts disadvantaged communities^[2] in the Valley. Sixty-four disadvantaged unincorporated communities – containing approximately 64,000 residents – received unsafe drinking water in 2018, and this number does not include residents on private domestic wells. Arsenic, uranium, and other natural and human-made compounds are present in many parts of the aquifers in the Valley, leading to violations of drinking water standards. Historic and continued nitrogen fertilizer and manure use has resulted in higher levels of nitrates and salts relative to naturally occurring levels in some parts of the Valley making water unsafe to drink in those areas. There are also extensive areas of groundwater contamination from industrial chemicals, most notably 1,2,3-TCP (trichloropropane).

Many homes are currently at risk of having no on-going supply of water.  During the 2020-2022 drought about 1,500 domestic wells in the S2J2 region were reported dry. Private domestic wells are particularly at risk of running dry because of their shallow depth. Approximately 70,000 Valley households rely on domestic wells for drinking water. Wells serving private homes continue to go dry even in non-drought years and falling groundwater levels are anticipated to impact up to 12,000 more wells in the next two decades.

Fixing drinking water infrastructure is costly, and this burden is disproportionately born by low-income households and communities in the Valley, as well as taxpayers through state assistance programs. The costs to treat contaminated water, dig new wells, and operate and maintain drinking water infrastructure are expensive, and many small communities cannot afford these investments. For homes with private domestic wells, digging a new well, depending on location, is estimated to cost up to $60,000, which is unaffordable for low-income households. Installing water filters and purchasing bottled water are not acceptable long-term solutions for residents to pay when experiencing contaminated water. For small community water systems, replacing new wells, installing treatment systems, and operating and maintaining distribution lines and meters are just some of the high costs that communities bear. In addition, the lack of adequate investment in safe, reliable, and affordable drinking water access for low-income communities of color and the lack of equitable representation in water management decisions means that disadvantaged communities, who often are not included in the decision process, are disproportionately affected by drinking water issues.

Solutions are urgently needed to ensure access to safe, reliable, and affordable water for all homes in the Valley.

[1] Disinvested is a term used for the Community Economic Resilience Fund (CERF) and includes the following factors:  i) Census tracts identified as “disadvantaged” by the California Environmental Protection Agency (CalEPA); ii) Census tracts with median household incomes at or below 80 percent of the statewide median income; iii) ”High poverty area” and ”High unemployment area” as designated by the California Governor’s Office of Business and Economic Development California Competes Tax Credit Program; and iv) California Native American Tribes as defined by the Native American Heritage Commission (NAHC) Tribal Consultation Policy (Urban Institute, 2023). Valley CERF Regional Plan Part 1

[2] A community with an annual median household income that is less than 80 percent of the statewide median household income (Water Code §79505.5)

The balance between available local water supplies and demand in the Valley has driven conflict in California water management for decades. Most portions of the Valley do not have sufficient water supply available from local streams, rivers, and groundwater to meet current demands without further depleting groundwater aquifers. In much of the Valley, water agencies have relied upon surface water contracts for imported water from the Sacramento-San Joaquin Delta and its tributaries through the Central Valley Project and State Water Project, to meet a portion of demands, particularly in the western and southern regions of the Valley. Many small cities and towns have relied on groundwater as a primary source of drinking water. Other regions on the east side of the Valley have historically had better access to local water resources, capturing water from the major rivers and streams originating in the Sierra Nevada Mountain range, south of the Delta. Still, other regions (known as “white areas or “undistricted areas”) have little access to local streams and rivers and little to no access to imported water supply from the Delta or storage.
Climate change is expected to contribute to the Valley’s water supply challenges. Although average annual total precipitation amounts are not expected to change significantly across the Sierra Nevada range, more precipitation is expected to fall as rain instead of snow. As a result, one of California’s most important water storage assets, the Sierra Nevada snowpack, is projected to be diminished. Climate change is also expected to result in longer, more severe drought episodes punctuated by shorter periods of heavy precipitation. Rain events can further stress surface and stormwater management systems, and reduced snowpack may reduce summer surface water flows and groundwater recharge. Climate change may result in less reliable and more volatile water supply and greater risks from both droughts and flood events, impacting Valley cities, towns, and farms.
The California Department of Water Resources designates overdrafted groundwater basins in California and the majority of the critically overdrafted basins are in the Valley. In a 2019 report, the Public Policy Institute of California estimated that over the last two decades there has been an average annual overdraft of 2.4 million-acre-feet (MAF) in the San Joaquin Valley. During the 2012-16 drought, the overdraft was estimated to be more than 8 MAF. Under current policies and programs, land fallowing would become the dominant means of balancing water demand and supply and it is estimated that 500,000 – 900,000 acres of productive farmland would have to come out of production in the San Joaquin Valley to balance demand (Hanak et al.). In the S2J2 region the annual overdraft is 1.5 MAF based on the PPIC study. The California Department of Water Resource estimates climate change could cause a 50 percent increase in demand which would translate to an estimated 2.3 MAF of overdraft if demand is unchanged. The California Department of Conservation estimates that, in a worst-case scenario, over 900,000 acres would need to be fallowed just in the four-county area to balance demand. Without any intervention and planning, this could lead to catastrophic impacts on the Valley’s economy, ecosystems, and communities.
This large gap between water demand and supply does not include the water necessary to support improved Valley ecosystems. As stakeholders in the Valley work to improve ecosystem function and connectivity, additional demands are anticipated.

Today, of the 17 million acres that make up the Valley, less than ten percent of the functional habitat remains, and many habitat areas are disconnected “islands” – too small to support sustainable populations of many fish and wildlife species. Significant quantities of water have been diverted from wetlands and floodplains by extensive water supply and flood control infrastructure to provide for farmland, grazing, and urban, residential, and commercial developments for people, displacing fish and wildlife habitat. Levees channelize floodwater towards the coast, bypassing and degrading important ecosystems in the Valley. Dams and other water diversion facilities are a vital part of the Valley’s water supply and flood control systems and have some benefits in regulating flow and temperature, but they also directly block fish passage and reduce instream flows at various times that can influence fish life cycles.
In addition to habitat loss and disconnection, fish and wildlife are facing similar climate change induced stress from increased temperatures and weather severity, along with a decrease in water availability. These challenges are especially acute for the 18 endangered species and 27 at-risk species that call the Valley home, and the millions of birds that use the Valley as an important resting place on the Pacific Flyway.
Importantly, reduced habitat availability does not only negatively impact wildlife; it removes outdoor places and opportunities for people to interact with the outdoors and nature. Studies have indicated that greater outdoor recreation opportunities benefit the physical, mental, and emotional health of all ages.
Management of the remaining habitat in the Valley is the responsibility of a combination of federal, state, and private entities. There are examples of collaborative habitat restoration and water supply projects that have been completed and more are underway with constructive partnerships between farmers, local water agencies, and environmental organizations. These partnerships are critical to meeting the Valley’s ecological needs. One example of such a partnership is River Partners’ Dos Rios project, a collaboration across diverse interests. It is the largest public-private floodplain restoration project in California, a leading example of “green infrastructure” that lowers flood risk, increases groundwater recharge capacity and brings life back to the San Joaquin Valley to protect endangered species. This type of activity needs to occur on a broader scale to help expand floodplains, wetlands, riparian, upland, and other habitat.

Most of the infrastructure that provides flood control benefits and stores and conveys water to Valley communities and agricultural lands is well over 70 years old. Current built infrastructure needs to be repaired, replaced, and expanded to deliver safe drinking water to Valley communities, support sustainable levels of agriculture, replenish groundwater basins, and expand environmental habitat areas. Infrastructure rehabilitation and expansion is needed to deliver water for agricultural and domestic uses. Domestic uses include residents who rely on both small and large community water systems as well as households on domestic drinking water wells. Infrastructure improvements will also be required to address the hydrologic impacts of climate change so that the capacity of conveyance and storage facilities can better take advantage of high flow events to mitigate the effects of prolonged dry periods.
Unsustainable groundwater withdrawal exacerbates infrastructure problems and, in some areas, has caused land subsidence. Land subsidence occurs when groundwater is extracted in excess of natural or managed replenishment, and the ground compacts and sometimes permanently sinks as the groundwater table declines. This compaction can damage roads, bridges, canals, buildings, and other infrastructure. Subsidence reduces conveyance and storage capacity, impacting these systems’ ability to deliver water for consumptive uses, habitat restoration, and groundwater replenishment. In the San Joaquin Valley, all the major conveyance systems – the California Aqueduct, the Delta Mendota Canal, and the Friant Kern Canal, have experienced diminished capacity due to subsidence. Subsidence also diminishes the aquifer’s ability to store and recharge groundwater in the future, further increasing the gap between water demand and supply in the Valley.

Various government policies and programs have tried to address water quality, supply, and access issues, along with environmental concerns, but are not producing the magnitude of success needed to address current or future challenges. Many of the current policies and programs lack flexibility and are oriented toward different objectives and administered by different agencies and levels of government. Although some funding is available through state and federal programs to help address these challenges, local governments and nonprofit organizations that support the necessary actions typically lack adequate staff capacity or resources to actively manage funding to allow them to complete the work themselves. Additional planning and technical assistance for local entities, DACs, and landowners is critical to accelerating success in this area.
In addition, economic instability is at the forefront of communities’ concerns. Local government property tax and sales tax revenues are likely to be reduced as more agricultural acreage goes out of production and shifts to other uses that require less water. It is unclear whether or what other revenue sources might offset that decline.
Implementing the “One Water” Investment Plan will require working closely with all levels of government and the private sector, especially local governments, where the rubber often meets the road in natural resource policy. Valley local governments are overwhelmed, and changes in water policy have imposed many unfunded mandates on them. They simply do not have the resources to fully do what is being asked of them. Ensuring that local counties, cities, and Groundwater Sustainability Agencies (GSAs) have the resources and capacity to do their part in implementing a sustainable and comprehensive water management program will be essential for success. This need to increase the capacity to engage and do the necessary work is critical for disadvantaged communities, state and federal agencies, and the private sector.