Water Quality & Quantity

Harmful Algae Blooms (HABs)

Harmful algal blooms (HABs) occur when large numbers of toxin-producing algae grow in bodies of water, often fueled by excess nutrients and warm temperatures. Exposure, which can occur through ingestion, skin contact, or inhalation, can cause a range of health effects, from skin rashes and respiratory irritation to liver damage, neurological effects, and gastrointestinal illness. Vulnerable populations, including children, the elderly, and those with preexisting conditions, are at greatest risk.

Research Needs

Research that supports effective monitoring, risk communication, and health-protective policy around Harmful Algal Blooms:

Research on patterns of human exposures and health impacts of HABs
Research that monitors and assesses HABs outbreaks in the Delta, Sierra Nevada, irrigation canals and rivers in the San Joaquin Valley, the Salton Sea region, and in Tribal communities throughout the state.
Research on the sources and impact of nutrients in water that contribute to HABs formation
Research that assesses health outcomes associated with improved HAB mitigation measures and policies

Background & Policy Context

Algae is an informal term for a wide range of simple, mostly aquatic plants found all over the world. Singled-celled phytoplankton (microalgae) and seaweed (macroalgae) are both considered algae. Sometimes, in certain conditions, algae grow very quickly, or “bloom.” When certain species of algae bloom (most commonly cyanobacteria in freshwater, and dinoflagellates or diatoms in saltwater), they can release toxins that make people and animals sick. These are referred to as Harmful Algal Blooms (HABS), and are a major source of both ecological and human health risk. Even non-toxic algal blooms can be harmful due to their density in the water, and as the bloom dies and decays, it can use up all the oxygen in the water and/or release harmful gases, including methane and hydrogen sulfide.

Environmental conditions that can lead to HABs include increased temperatures, nutrient pollution (often from fertilizers or run off from wastewater treatment or other human activities), increases in atmospheric CO2, and changes in salinity.

Human exposure to HABS may occur through ingestion of contaminated drinking water or shellfish, skin contact, or inhalation of harmful gases as the bloom decays. Unhoused populations living on or near shorelines who use surface waters to bath, clean, or drink are particularly vulnerable. HABs exposures have been associated with respiratory, gastrointestinal, and neurologic health impacts, as well as skin irritation and liver damage.

HABs are a major concern in the San Francisco Bay Delta, including communities in the Stockton area. There is an upcoming Delta-wide HABs monitoring and mitigation strategy in development, and advocacy organizations such as Little Manila Rising and Restore the Delta, state agencies such as the Delta Stewardship Council, and various tribes including the Big Valley Band of Pomo Indians and others around Clear Lake are conducting water quality monitoring and risk communication around HABs. Additional public resources around HABs include the California Department of Public Health’s Marine Biotoxin Monitoring Program, the State Water Resources Board’s Freshwater and Estuarine Harmful Algal Bloom (FHAB) Program, the California Harmful Algal Bloom Monitoring and Alert Program, and the California Cyanobacteria and Harmful Algal Bloom (CCHAB) Network.

Additional Resources

Microplastics

Microplastics, defined as tiny plastic particles less than 5mm in size, have become ubiquitous in the environment, including food, water, and even human tissues. Potential health risks may include inflammation, oxidative stress, and disruption of metabolic or endocrine functions, though direct causal links to specific diseases in humans remain under investigation.

Research Needs

Research that characterizes the biological pathways of microplastics and their effects on human health:

Human risk assessments: Research on the human health risks of exposures to microplastics in food and water (especially in bottled drinking water, plastic-wrapped food, and associated with biosolids use in agriculture).
Pathogen transfer: Research on how microplastics transfer pathogens from biosolids to soils, plants, and ground or surface waters.
Exposure studies: Research on the routes and levels of human exposure to microplastics.

Background & Policy Context

Plastic waste does not biodegrade, but rather breaks down into smaller and smaller pieces, which have commonly become known as microplastics. Microplastics are defined as plastics smaller than 5mm, and can be either primary (manufactured at microplastic size as abrasives or for use in cosmetics) or secondary, resulting from the breakdown of larger plastic items (including synthetic clothing).

Microplastics are everywhere – in water, air, food, and in the bodies of animals and humans - yet little is known about how they impact human health. Their physical and chemical characteristics are highly diverse, and they can both adsorb chemical contaminants from the environment and host a biofilm of microorganisms. Theoretically, microplastics may pose physical (irritation or inflammation), chemical (toxic), or microbiological (as a vector for pathogens) hazards to human health.

In 2018, SB 1263 added Section 116376 to California’s Health and Safety Code, making California the first government to commit to monitoring for microplastics in drinking water. SB 1263 also authorized the Ocean Protection Council, in collaboration with the State Water Resources Control Board and the Office of Environmental Health Hazard Assessment, to develop a Statewide Microplastics Strategy, which was adopted in 2022, outlining additional steps to address microplastic pollution.

Section 116376 required the State Water Resources Control Board adopt an official definition of microplastics for regulatory purposes (2020), and to develop the world’s first standardized methods for testing for microplastics in drinking water by 2021, which it did in collaboration with Ocean Protection Council and the Southern California Coastal Water Research Program. These include methods for monitoring microplastics in drinking water, surface water, sediment, and fish tissue. The state is required to conduct four years of testing starting in 2023, and to report on microplastics in drinking water, after which it will consider issuing a notification level or other guidance to aid in interpretation of microplastics testing results, and to accredit qualified labs in California to analyze microplastics.

Plastic waste disproportionately impacts many of the same groups impacted by other forms of environmental health hazards. Routes of exposure particularly relevant in California include exposure via consumption of bottled water, consumption of food in plastic packaging, and exposure via runoff from biosolids-amended cropland.

Bottled water: Low income people in areas with polluted drinking water often depend on bottled water as a substitute, whether informally or through state water replacement programs funded under SAFER. Bottled water is not regulated by the Clean Water Act / EPA, but instead through the U.S. Food and Drug Administration. While standards for tap and bottled water are very similar between the two agencies, the FDA does not monitor bottled water to the same degree as the EPA monitors tap water and studies have shown it does not always meet standards when independently tested (note that California’s Department of Public Health requires its own bottled water testing. It is also at higher risk for containing microplastics.

In 2024, California passed legislation that will require bottled water manufacturers to report on the levels of microplastics found in both their source water and their final product once a state standard is set.

Water vending machines: Contamination of water vending machines (sometimes called “ Waterias”) also represents an unspecified risk and growing area of concern. Water vending machines take city tap water and run it through a filtration system before dispensing it to customers at a price that is lower than bottled water but more expensive than tap water. They have been licensed by the California Department of Public Health since 1989, with approximately 10,000 kiosks statewide. While they are legally required to be inspected and sanitized monthly by their operators, very few are actually inspected by the state, and private testing shows that some may not meet public water quality standards (largely due to lack of maintenance). They are also only designed to remove secondary contaminants, which are those affecting the flavor and smell of the water. If local water is unsafe to drink due to health-based contaminants (e.g. nitrates or arsenic), vended water that depends on that supply will also be unsafe, and may introduce additional health-based contaminants such as coliform bacteria, which vending machines are only required to be tested for every 6 months. Vended water is also generally used to fill plastic containers, some of which may not have been designed for reuse, potentially introducing additional microplastics and other forms of plastic pollution (e.g. toxic chemicals, endocrine disruptors) into drinking water.

Food packaging: Food is stored, transported, and consumed in plastic containers which may leach chemicals and microplastics, particularly when they are exposed to sunlight, water, temperature change, and physical stress. Low income people tend to buy more packaged and processed foods for a variety of reasons, including cost, availability, and shelf life, potentially leading to higher microplastics exposure via this route.

Biosolids: Biosolids is shorthand for treated municipal sewage sludge, which can be used as fertilizer, but may also contain contaminants such as trace organic compounds, heavy metals, and pathogens. Biosolids have also been shown to contain high levels of microplastics as compared to other soil amendments. Most of the farms using biosolids in California are large industrial facilities located in low-income rural areas of the state, such as the San Joaquin Valley.

Additional Resources

Safe and Affordable Funding for Equity and Resilience (SAFER) Program Implementation

California’s Safe and Affordable Funding for Equity and Resilience (SAFER) Program invests $130m per year in underperforming and at-risk small drinking water systems. California-specific research can help the state prioritize investments that will have the greatest impact on improving public health.

Research Needs

Research on whether California’s SAFER Program is reducing exposures and/or improving health outcomes in communities that are most impacted by water contamination, such as:

Research identifying higher risk contaminants to human health in small water systems and domestic wells, which could help prioritize funding by the State Water Board. There is a particular interest in research that expands testing of domestic wells for contaminants of concern.
Research that identifies small water systems at high risk of failure and their associated health impacts. This could enable the provision of funding to disadvantaged communities before their systems underperform or fail
Research that identifies short and long term health impacts related to ingestion and absorption of contaminants found in small water systems and domestics wells
Research that assesses water resource allocations under SB 200 (i.e. which small districts are accessing state funding and for those that are not, barriers faced to funding access, and the impact on health disparities)
Research on the effectiveness of interventions under the SAFER program in improving public health outcomes (in particular, consolidation with larger water systems versus residential-scale Point of Use (POU) or Point of Access (POA) water treatment systems)
Research on the impact of water affordability on public health outcomes.
Research supporting the development of health-protective Tribal beneficial use designations (i.e. what are tribal uses, what quality standards are needed to protect those uses?)

Background & Policy Context

In 2019, California SB 200 established the Safe and Affordable Funding for Equity and Resilience (SAFER) Program, which provides $130 million per year over 10 years in funding support for underperforming and at-risk small water systems through the Safe and Affordable Drinking Water Fund. The Fund’s Expenditure Plan is updated each year based on an annual Drinking Water Needs Assessment.

There is currently limited testing of domestic wells by public agencies, which represents a gap in the knowledge base needed for effective regulation and investments. The California State Water Resource Control Board’s Groundwater Ambient Monitoring and Assessment Program (GAMA) provides various tools for assessing groundwater quality using available data, as does EHSC CAC-member Community Water Center.

Drought Resiliency

Drought can negatively impact public health both by reducing access to water and by reducing water quality. During drought years, groundwater levels drop, which can concentrate contaminants (i.e. naturally occurring arsenic, nitrates from agriculture) or cause more polluted shallow zones of groundwater to migrate toward wells that draw from deeper aquifers. In rural Central Valley communities, many residents use shallow domestic wells or aging infrastructure that is particularly vulnerable when the water table falls. Drought can also contribute to reduced air quality through dust and increasing wildfire risk.

Research Needs

Research on effective ways to improve water quality and public health outcomes during periods of drought, such as:

Research on strategies or technologies to protect drinking water quality and human health during drought conditions
Research on health benefits of effective remediation of residential and community wells, including both toxic contamination and salt water intrusion
A cost/benefit analysis of various drinking water protection strategies, including connecting to municipal water services
Research evaluating the drought resiliency strategies counties and water systems have put into place under SB 552
Research on quality and public perceptions of recycled water, compared to other drinking water sources (i.e. while there is an “ick” factor, does heavily treated recycled water actually have less contaminants?; are there new contaminants introduced by water recycling?)
Research on exposure levels, pathways, and/or health impacts associated with the reuse of water used in oil and gas exploration (i.e. “produced water, which in California can be diluted and used on cropland)

Background & Policy Context

Recent bills related to drought response in California include CA SB 552 Drought Resilient Communities Act, which was passed in September 2021 and requires counties and water systems to have drought resiliency plans, and the Safe Drinking Water, Wildfire Prevention, Drought Preparedness, and Clean Air Bond Act (SB 867), which provides $5.2B in funds for drought, flood, and water resilience programs. California also receives funds from the national Infrastructure Investment and Jobs Act of 2021, which includes support for addressing drought (set to expire in 2026 if not renewed).

Recycled Water: California has passed SB 918 (2010) and SB 322 (2013) required the State Water Board to investigate and report (2016) on the feasibility of treating and returning wastewater directly into public drinking water systems (referred to as Direct Potable Reuse or DPR). In 2017, AB 574 mandated that the State Water Board’s Division of Drinking Water (DDW) develop and adopt health-protective criteria for water recycling, which went into effect on October 1, 2024.

Additional Resources

California’s Sustainable Groundwater Management Act Implementation

Research Needs

The Sustainable Groundwater Management Act (SGMA) requires local Groundwater Sustainability Agencies (GSAs) in high- and medium-priority basins to develop and implement Groundwater Sustainability Plans (GSPs) or Alternatives to GSPs, which are submitted to the Department of Water Resources’ (DWR) SGMA Portal. SGMA went into effect in 2017 and is in the process of implementation across the state.

Research that supports the development of effective sustainable groundwater management systems that improve public health outcomes, particularly in marginalized communities, such as:

Research on the public health impacts of new groundwater management strategies (e.g., limitations on groundwater extraction, groundwater recharge) being deployed as part of SGMA implementation
Research on the impact of wildfire on surface and groundwater quality, in particular in cases of proposed groundwater recharge under SGMA using surface water in wildfire impacted regions
Research identifying gaps in SGMA related to public health that could be addressed by future legislation or regulatory rule-making
Research on the effectiveness, transparency, and responsiveness of Groundwater Sustainability Agencies (GSAs) in addressing public health concerns in disadvantaged communities
Research on the impact of subsidence on flood risk (i.e. where subsidence may be making communities more at risk of flooding)
Research that characterizes the potential water quality and health impacts of groundwater recharge quality in areas that have subsidence
Research that supports health-protective groundwater management of groundwater dependent ecosystems.* This is of particular concern to Tribal nations and communities who often rely on these surface waters and associated ecosystems. *Abbreviated GDEs, see Natural Communities Commonly Associated with Groundwater for full definition and public data), these are highly interconnected ground/surface water systems in which groundwater pumping directly impacts the health of the surface ecosystem, including various ecosystem services.

Background & Policy Context

California’s Sustainable Groundwater Management Act (SGMA) requires Groundwater Sustainability Plans (GSPs) to address groundwater level declines, groundwater storage reductions, land subsidence, depletion of interconnected surface waters, sea water intrusion, and water quality degradation. However, some groundwater management practices may produce improvements in one area and deteriorations in another. For example, groundwater recharge can both positively and negatively impact drinking water quality (and thus public health) depending on a number of factors related to both the aquifer and the process used.

Note: the California Department of Water Resources is expected to come out with guidance soon for Groundwater Sustainability Agencies to incorporate Groundwater Dependent Ecosystems into their plans.

Additional Resources

Wastewater Management

Many rural residents in California rely on septic systems for wastewater management, which may be overburdened or inappropriate for the soil conditions. This can result in soil and water contamination, including the contamination of residential wells.

Research Needs

Research that informs the development and implementation of safe wastewater systems in rural communities, minimizing contamination risks:

Research that compares resident well contamination levels in communities that use septic systems, to those with access to alternative wastewater management facilities
Research that identifies pollutants caused by improper wastewater management
Research into alternative wastewater management systems, or changes that can be made to septic systems to make them more appropriate for various soil environments
Research that develops cost effective tools to monitor soil and water quality around septic tanks

Background & Policy Context

The state has the authority to require local municipalities/wastewater providers to provide connections to residents on septic systems, but historically has rarely done so. The 2021 California state budget included $1.3 billion over 4 years for “drinking water and wastewater infrastructure, with a focus on small and disadvantaged communities.”

Additional Resources

Per- and Polyfluoroalkyl Substances (PFAS) Regulation & Remediation

Per- and polyfluoroalkyl substances (PFAS) are a family of human-made chemicals that repel oil and water and are used across a range of industries and consumer products -- including food packaging, waterproof clothing and upholstery, and at high concentrations in Class B firefighting foam (used for flammable liquid fires). They are associated with a range of adverse health effects, including immune, reproductive, and developmental impacts and increased risk of testicular and kidney cancer.

Research Needs

Research that informs the development and implementation of state policies that mandate PFAS remediation of impacted water systems and prevent future contamination, such as:

Research on improved methods of testing for the presence of PFAS chemicals, including detection of low concentrations in both environmental and biological samples
Research that expands water sampling, particularly of small water systems and domestic wells, both in proximity to military bases and airports and in locations of unknown risk
Research on the potential human health benefits/impacts of using alternatives to PFAS
Research on the efficacy and further development of effective, health protective PFAS remediation and mitigation strategies/technologies
Research on the human health effects of the use of PFAS-based firefighting foams during urban-interface wildfires and the impact on surface and groundwater quality in impacted communities
Research on the human health impacts of newer short-chain PFAS chemicals in comparison to the older long-chain PFAS that they are replacing
Research on the human health impacts of exposure to mixtures of PFAS and/or PFAS in combination with other chemicals

Background

Key potential environmental sources of PFAS exposure include military bases, airports, landfills, wastewater treatment facilities, and other industrial or manufacturing facilities. A national monitoring survey in 2013-2015 found more detections of PFAS in California drinking water sources than any other state, and a 2023 EPA report shows extensive contamination nationwide (see Environmental Working Group’s mapping tool for California data). Remediation of PFAS contamination is technically challenging due to its unique characteristics.

Firefighting foam is of particular concern in California due to its use on military bases, which can be a major source of groundwater contamination (and around which federal/state responsibilities for remediation are complex and unresolved). It is also an area of emerging concern in wildfire zones with an urban interface, where gas stations or other industrial facilities at risk for flammable liquid fires may be impacted. In 2020, California SB1044 required PFAS chemicals to be phased out of Class B firefighting foam by 2022 for most uses, with waivers available to certain facilities, including oil refineries, through 2032.

Policy Context

Classification at federal and state levels: The EPA classified PFAS as an “emerging contaminant” in 2016 and established a (non-enforceable and non-regulatory) lifetime health advisory level. EPA updated these drinking water health advisories for PFOA and PFOS in 2022, added advisories for PFBS and HFPO, and made $2b in grant funding available for states to address emerging drinking water contaminants like PFAS. In March 2023, EPA proposed a National Primary Drinking Water Regulation (NPDWR) for six PFAS (PFOA, PFOS, PFHxS, PFNA, PFBS, and HFPO-DA).

Finalized in April, 2024, these regulations establish both legally enforceable Maximum Contaminant Levels (MCLs) and health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for six PFAS, and were paired with $1 billion in new funding for PFAS testing and water treatment.

The California State Water Resources Control Board Division of Drinking Water (SWRCB-DDW) established notification and response levels for three PFAS chemicals in 2021 and 2022, including: perfluorooctanoate (PFOA), perfluorooctanesulfonate (PFOS), perfluorobutane sulfonate (PFBS), and perfluorohexane sulfonic acid (PFHxS). If these are detected at or above the response level, they recommend that a water source is taken out of service. Community groups would like the Office of Environmental Health Hazard Assessment (OEHHA) to develop a public health goal (PHG) for PFAS as a class, allowing the effective regulation of all (approximately 4,700) PFAS chemicals in drinking water.

California-specific legislation: In 2021, California AB 1200 and AB 652 were signed by the Governor, requiring disclosure of PFAS used in cookware and prohibiting the distribution and sale of food packaging and children’s products containing PFAS. The 2021-22 California state budget includes $4.3 million and 21 permanent positions to the State Water Resources Control Board to oversee cleanup of contaminants including PFAS. Orange County received a $131 million EPA Water

Infrastructure Finance and Innovation Act (WIFIA) Loan in 2021, which will support 35 PFAS treatment systems for 59 impacted wells in the Orange County Water District’s service area. These treatment systems are currently under design and are expected to be constructed in the next two years.

Two additional PFAS-related bills were passed in 2022 and will go into effect January 1, 2025, including The Safer Clothes and Textiles Act (AB 1817), which will ban the sale of clothing and textile products in California containing PFAS, and The PFAS-Free Beauty Act (AB2771), which would ban the entire class of PFAS from beauty and personal care products.

Water Quality & Quantity

Building the Evidence Base for Health-Protective Water Policy in California

Harmful Algae Blooms (HABs)

Research Needs

Background & Policy Context

Additional Resources

Microplastics

Research Needs

Background & Policy Context

Additional Resources

Safe and Affordable Funding for Equity and Resilience (SAFER) Program Implementation

Research Needs

Background & Policy Context

Drought Resiliency

Research Needs

Background & Policy Context

Additional Resources

California’s Sustainable Groundwater Management Act Implementation

Research Needs

Background & Policy Context

Additional Resources

Wastewater Management

Research Needs

Background & Policy Context

Additional Resources

Per- and Polyfluoroalkyl Substances (PFAS) Regulation & Remediation

Research Needs

Background

Policy Context

Additional Resources