. 2022 Sep 21;130(9):097701. doi: 10.1289/EHP10758

Table 1.

Key socioeconomic and drinking water-related characteristics for the four study sites.

	Allensworth	City of Delano	City of McFarland	Kern Valley State Prison
Demographic and economic indicators
Population: ACS estimate^a	575 ( $\pm 162$ )^b	52,886 ( $\pm 31$ )^b	14,823 ( $\pm 34$ )^b	Data unavailable
Population: SDWIS estimate^c	521	52,658	15,105	5,300
Median household income^a^,^d	$33,214 dollars$ ( $\pm $ 14,921$ )^b	$43,641 dollars$ ( $\pm $ 4,601$ )^b	$35,346 dollars$ ( $\pm $ 3,476$ )^b	Data unavailable
Poverty rate (CA $mean equals 13.11 percent$ ) (%)^a^,^e	47.63	19.32	30.21	Data unavailable
Governance and water supply
Type of local governance	Community services district	City council	City council	NA
Active public groundwater supply wells (as of 2021, Q3) ( $n$ )^c	2	14	3	2
SDWA violation data: 2001–2021^f
Arsenic MCL violations ( $n$ )^c^,^g	11	27	12	19
Arsenic monitoring or treatment technique violations ( $n$ )^c	3	0	8	0
Most recent MCL violation: arsenic (as of 2021, Q3)^c	Q2 of 2020	Q4 of 2012	Q1 of 2013	Q4 of 2012
Most recent MCL violation: any (as of 2021, Q3)	2020 arsenic violation	2019 1,2,3-trichloro-propane violation^h	2019 1,2,3-trichloro-propane violation^h	2019 total coliform rule violation
Sampling results from served water sources: 2001–2021ⁱ	$lowercase italic n equals 150$	$lowercase italic n equals 1,714$	$lowercase italic n equals 136$	$lowercase italic n equals 426$
Mean arsenic level $\pm SD$ ( $μ g / L$ )	9.27 $\pm 2.88$	3.41 $\pm 6.71$	8.43 $\pm 6.68$	7.51 $\pm 8.19$
Median arsenic level (IQR) ( $μ g / L$ )	8.95 (5.00)	0 (4.27)	7.95 (4.43)	5.00 (5.00)
Min. and max. arsenic level ( $μ g / L$ )	3.7, 23	0, 56	2, 76	0, 50.4
Samples exceeding $10 micrograms per liter$ arsenic^c	34% ( $lowercase italic n equals 51$ , max: $23 micrograms per liter$ )	8% ( $lowercase italic n equals 141$ , max: $56 micrograms per liter$ )	20% ( $lowercase italic n equals 27$ , max: $76 micrograms per liter$ )	19% ( $lowercase italic n equals 81$ , max: $50 micrograms per liter$ )
Posttreatment or post-blending samples exceeding $10 micrograms per liter$ arsenic^c^,^j	18% ( $lowercase italic n equals 13$ , max: $23 micrograms per liter$ )	0% ( $lowercase italic n equals 0$ of 1,250)	13% ( $lowercase italic n equals 9$ , max: $18 micrograms per liter$ )	12% ( $lowercase italic n equals 47$ , max: $50 micrograms per liter$ )
Arsenic treatment status and funding
Approximate state funding for arsenic remediation^k	$496,000 dollars$ interim solutions; $390,000 dollars$ planning grant	$20.5 million dollars$ loan and $818,000 dollars$ construction grant	$232,000 dollars$ planning grant, $3.7 million dollars$ construction grant	$6.2 million dollars$ planning and construction funding
Arsenic treatment status (as of 2021, Q3)^c	No, but the water from two wells was blended	Yes, wellhead treatment on four wells	Yes, wellhead treatment on one well	Yes, treatment on blended water

Note: Socioeconomic data and results from our drinking water analyses are presented for four neighboring community water systems in California’s southern San Joaquin Valley. Analyses are based on $lowercase italic n equals 3,984$ water quality monitoring samples taken across these four systems from 2001 to 2021, of which $lowercase italic n equals 2,426$ samples were from served water sources. Samples below the detection limit were included as reported in California’s Drinking Water Watch.⁹ ACS, American Community Survey; CA, California; IQR, interquartile range; max, maximum; MCL, maximum contaminant level; min, minimum; NA, not applicable; Q, quarter; SD, standard deviation; SDWA, Safe Drinking Water Act; SDWIS, Safe Drinking Water Information System.

^{^a}

Information from 5-y ACS 2019 estimates (most recent year available) for these census-designated geographies.

^{^b}

Margin of error bounds reflect a 90% confidence interval around the estimate.

^{^c}

Information calculated based on data from California’s Drinking Water Watch,⁹ which is partly sourced from the U.S. Environmental Protection Agency’s SDWIS.

^{^d}

Median household income in the past 12 months, in 2019 inflation-adjusted U.S. dollars.

^{^e}

Percentage of the population whose income in the past 12 months was below the federal poverty level.

^{^f}

SDWA violation data.

^{^g}

The MCL is the highest level of a contaminant allowed in drinking water. MCL violations are assigned by the Division of Drinking Water when a public water system exceeds the MCL.

^{^h}

California’s state MCL for 1,2,3-trichloropropane is $0.005 micrograms per liter$ .

^ⁱ

Served water sources refers to water sources served to community water system customers, which excludes raw water samples from treated and blended sources.

^{^j}

Water quality samples taken after arsenic treatment (i.e., in Delano, McFarland, and Kern Valley State Prison), or after blending the water from two wells without treatment (i.e., in Allensworth).

^{^k}

Information from the California Department of Corrections and Rehabilitation (2013)⁸ and California State Water Resources Control Board (CSWRCB) Department of Financial Assistance (DFA).⁹ DFA confirmed funding for Allensworth, Delano, and McFarland from 2014 to 2021 (B. Chase, Supervising Water Resource Control Engineer, CSWRCB, personal communication). “Interim solutions” refers to grant funding for bottled water deliveries and school water filling stations.