Who governs California’s drinking water systems?

By Kristin Dobbin and Amanda Fencl

A key feature of California’s drinking water system is the large number of individual water systems. There are approximately 3,000 Community Water Systems (CWSs) in the state, meaning systems that serve a residential population year-round (the remaining 5,000 of the state’s 8,000 Public Water Systems are non-community systems serve places like schools, daycare, hospitals, campgrounds, or businesses that serve at least 25 people but have transient or non-residential populations. Additionally there are an unknown number of unregulated water systems in the state that do not meet the 25 person or 15 connection size threshold for regulation under the Safe Drinking Water Act. This extreme decentralization and fragmentation of governance results from local land use decisions, politics and a preference for local control by the state and locals. While allowing for local control and flexibility, this arrangement has not guaranteed safe drinking water for all (NYT 2019; Politifact 2019; SacBee 2018). More than a million Californians lack safe water, primarily in low-income communities, communities of color, indigenous communities and rural communities.

Particularly for CWSs, governance is critical to resolving the crisis (Wutich et al. 2016; Newig and Fritsch 2009). The number of systems and diversity of structures under which they operate, however, is a challenge for policy and practice. For system consolidations, for example, solutions need to be developed and implemented with explicit consideration for how system governance affects representation and accountability (Nylen, Pannu, & Kiparsky 2018). And in newly formed Groundwater Sustainability Agencies, disadvantaged communities without CWSs that are public agencies (e.g., mutual water companies) are significantly less likely to be represented as decision-makers (Dobbin and Lubell 2019). Better understanding the existing landscape of CWSs in California is key to understanding how governance can address the entrenched disparities.

An important first step in this direction is to identify and analyze the range of CWS governance arrangements. To do so, we coded each of the 2,895 active CWSs in the state as of the end of 2018. Where possible, we relied on standardized names reflecting specific public district types (e.g. Community Services Districts, County Service Areas), and where not, we employed Consumer Confidence Reports, websites, tax filings and general Google searches using the system’s name and location to identify its specific organization types such as Mutual Water Companies or Property Associations. We also cross-referenced our data with existing lists such as the Public Utility Commission’s list of Investor-Owned Water Utilities. Ultimately, we identified 26 distinct system types as defined by a system’s legal structure/derived authority, who operates it and/or who it serves. These 26 types are aggregated into nine governance categories and classified as either publicly or privately owned entities. The table below summarizes these findings.

Table 1. Breakdown of California’s Community Water Systems by governance category and type

# of CWSs Median population served # of
CWSs w/ violations
Average # violations per CWS*
All CWSs  (PWS with > 15 connections or 25 people) 2,895 287 854 2.27
Publicly Owned CWSs 1,166 2,984 295 1.92
City: City (315); Special Act District (2) 317 22,795 80 1.43
County Service Area (77); Maintenance District (46); County Waterworks District (27); County Sheriff (12); County Dept. (excluding sheriff) (11); Special Act District (8);
Resort Improvement District (2)
183 350 55 3.08
Joint Powers Authority 12 109,254 0
Independent Special Districts:
Community Services District (185); County Water District (165); Public Utility District (53); Irrigation District (51); Special Act District (34); California Water District (32); Municipal Water District (31); Sanitary District (6); Municipal Utility District (3); Water Conservation District (3); Resort Improvement District (2); Resource Conservation District (1)
566 1,885 132 1.8
State and Federal: Federal (38); State (50) 88 2,200 28 2.36
Privately Owned CWSs 1729 126 559 2.51
Investor Owned Utility 220 1,695 39 1.49
Mobile Home Parks 375 108 124 2.3
User Owned Utilities

Mutual Water Company (582);
Property / Homeowners Associations (70)

652 124 218 2.34
Other private systems 482 79 178 3.36
*SDWA violation data was calculated by combining two data sources. The first is 2012- 2018 documented health-based violations from the State Board’s Human Right to Water portal, which excludes total coliform violations (SWRCB 2018). Because of this exclusion, we added Total Coliform Rule (TCR) health-based violations for each system from the SDWIS federal reports database (EPA 2019). When combined, the total number of CWSs with > 1 violation jumps from 525 to 854. The average number of violations per system in the last column is the average across all systems in each governance category.

From this analysis, four findings stand out:

1. There is considerable diversity in governance structures among CWSs, with greater diversity for public and small systems. As previously mentioned, we identified 26 distinct governance types among the 2,895 CWSs. Public CWSs make up 21 of these types, including 12 distinct types of independent special districts. Two types, Special Act Districts and Resort Improvement Districts appear in multiple governance categories because their enabling legislation set forth different options for composing their governing boards. The most frequent types of public systems are cities (315), Community Services Districts (185), and County Water Districts (165). There are five types of privately owned CWSs, including a catch-all category for “other private” systems representing for-profit, not-investor owned systems that we were unable to further disaggregate. Mutual Water Companies are the most common type of private CWS (582), followed by “other privates” (482), and mobile home parks (375). Using the median population served to classify each type as being comprised of either predominantly small (< 10,000 people served) or large ( > 10,000 people served) systems. Five types are predominantly large systems: Water Conservation Districts, Joint Powers Authorities, Resource Conservation Districts, Municipal Water Districts and Cities. The remaining twenty-one types are predominantly small systems.

Fig 1

2. System ownership and size are inversely related. While Most Californians (95%) get their water from 475 systems that are large (30%) or very large (65%), most (84%, 2,420) of California’s CWS serve less than 10,000 people. These smaller systems are responsible for drinking water provision to approximately 2.3 million people. 68% of such systems are privately owned (n=1,644), compared to just 18% of larger systems (n= 82).

Fig 2

3. Overall, around one-third of systems in the state have had a health-based violation in the last 7 years, but these incidents are not evenly spread across all governance categories. California’s CWSs have an average of 2.27 violations per system between 2012 and 2018. More information, however, can be gained by summarizing violations by governance category as we do in the table above. Excluding Joint Powers Agreements, where all twelve systems had zero violations, cities have the lowest average, just 1.43 violations per system over the seven years. In comparison, “other private” systems had an average of 3.36 violations followed by county operated systems with an average of 3.08 per system.

4. Health-based violations incidents are also not evenly spread across all system sizes in the last 7 years. As other studies have consistently shown, smaller systems have a harder time delivering safe water. Small and very small systems account 76% of all CWSs and 88% of the total violations in the data. Looking just at the 1,732 very small systems serving less than 500 people, five governance categories, on average, all have more violations than the statewide average: County (4.03), “other private” (3.6), Investor Owned Utilities (2.54), User Owned Utilities (2.51), and Mobile Home Parks (2.35).

Kristin Dobbin is a PhD student in Ecology at UC Davis studying regional water management and drinking water disparities in California. Amanda Fencl recently completed her PhD in Geography at UC Davis and is now a Postdoctoral Research Associate at Texas A&M University.

Further Reading

Dobbin, K. B. & A. L. Fencl (2021). Institutional diversity and safe drinking water provision in the United States. Utilities Policy, 73. DOI: 10.1016/j.jup.2021.101306.

Nylen, Pannu & Kiparsky (2018). Learning from California’s Experience with Small Water System Consolidations: A workshop synthesis. Center for Law, Energy and the Environment, UC Berkeley.

McFarlane, K., & Harris, L. M. (2018). Small systems, big challenges: review of small drinking water system governance. Environmental Reviews, 26(4), 378-395. DOI: 10.1139/er-2018-0033.

Teodoro, M. (2019). Grow to Shrink, Shrink to Grow. June 27, 2019. Mannyteodoro.com.

London et al. (2018)  The Struggle for Water Justice: Disadvantaged Unincorporated Communities in California’s San Joaquin Valley.  Center for Regional Change, UC Davis.

Pannu (2012) Drinking Water and Exclusion: A Case Study from California’s Central Valley. 100 Calif. L. Rev. 223.

Ekstrom et al. (2018)  Drought Management and Climate Adaptation of Small, Self-Sufficient Drinking Water Systems in California. California’s Fourth Climate Change Assessment, California Natural Resources Agency. Publication No. CCCA4-CNRA-2018-004.

About jaylund

Professor of Civil and Environmental Engineering Director, Center for Watershed Sciences University of California - Davis
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5 Responses to Who governs California’s drinking water systems?

  1. Bruce Macler says:

    Total coliform bacteria detections are no longer considered drinking water public health violations, since they are primarily indicative of breaches in the distribution system and not imminent potential for disease. I am curious why you decided to add them into the violations mix, and if your results would be different if you took them out?

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