Contra Costa's Jail Costs Ran 54% Above What It Told Supervisors

Contra Costa County's Sheriff's Office told the Board of Supervisors the average daily cost of jailing an adult was $257.▸ The county's own civil grand jury -- a panel of county residents empaneled each year by the Superior Court specifically to investigate local government operations -- spent months pulling cost data directly from the County Administrator's Office and Detention Health, and found the real figure was $396: 54% higher. The gap is not a dispute over numbers; it's a dispute over what counts. The Sheriff's quarterly report tallies only its own department's direct expenses. It leaves out the medical and mental-health costs Contra Costa Health bears for the same people, in the same jails, on the same days.

Contra Costa's Detention Health division -- part of the county's health department, not the Sheriff's Office -- provides medical and mental-health care inside the county's three adult detention facilities.▸ Its costs are real and substantial: the grand jury's Table 2 shows the costs booked in three cost centers -- $33.5 million tied specifically to Martinez Detention Facility, $10.4 million split between West County and Marsh Creek by population, and a third, $7.3 million mental-health-specific center apportioned across all three facilities (45% to Martinez, 51% to West County, 4% to Marsh Creek). None of it shows up in the $257 figure the Sheriff's Office reports each quarter. The grand jury did not accuse the Sheriff's Office of concealment -- its report calls the omission "understandable," since Detention Health's costs sit in a different department's budget -- but it found the effect is the same regardless of intent: the number elected supervisors see understates what the county actually spends to run its jails.

The grand jury's full-cost figure breaks down unevenly across the county's three facilities.▸ West County Detention Facility in Richmond, the largest by population, runs $278 a day per person. Martinez Detention Facility, the county's intake jail, runs $511. And Marsh Creek Detention Facility -- a minimum-security "farm" facility on the side of Mt. Diablo, nicknamed for its rural setting -- runs $627 a day, the highest of the three, despite housing the fewest people: an average of 37 a day in 2025, against a rated capacity of 188. That's 20% utilization. The county has explored closing Marsh Creek before, including a four-month closure during the early pandemic, but the grand jury's report is careful to note that shutting it down would not produce a full "saving" of the roughly $8 million it costs to run annually -- though the report says there is potential for savings on operating costs, plus a possible benefit from repurposing or selling the property. Even so, the grand jury's Recommendation R5 asks the Board of Supervisors to consider closing Marsh Creek by July 1, 2027.

Contra Costa's Custody Alternative Facility (CAF) program -- which includes electronic home detention (EHD), remote alcohol monitoring, and a work-release track -- is the county's answer to jail crowding and cost.▸ The Sheriff's own Quarterly Oversight Report compares CAF's $29 daily cost to detention's $257, a nearly nine-to-one gap the county cites as evidence the program saves money. But that comparison uses the same incomplete $257 detention figure the grand jury flagged.

Per a companion grand jury report on CAF and EHD specifically, the $29 figure has its own blind spot.▸ CAF blends three programs with very different costs -- the Sheriff's Work Alternative Program (SWAP), electronic home detention, and SCRAM alcohol monitoring -- into one average, and the grand jury's Finding F5 states the Sheriff's Office has never separately reported what each costs to run. Because SWAP participants are the largest group and the cheapest to supervise, that blend likely understates what EHD and SCRAM alone cost.

The same companion report found a gap in who can access CAF at all.▸ In the past four years, 1,014 people referred by a judge to electronic home detention were disqualified -- typically for being unhoused, living with someone who won't comply with monitoring requirements, lacking a working cell phone, or having an outstanding warrant. Because California's EHD statute requires participants to remain at a fixed residence, the Sheriff's Office disqualifies unhoused people from the cheaper option entirely, routing them instead toward the county's more expensive jail beds. The grand jury also found the Sheriff's current EHD policy, revised as recently as November 2025, does not lay out an individual's right to appeal a denial -- even though the state penal code the program operates under requires written notice of appeal rights.

The report doesn't just document the gap; it tells the county what to do about it, and assigns the two responsible offices different clocks.▸ Recommendation R1 asks the Board of Supervisors to consider requiring an audit to determine the full cost of the adult detention facilities by January 1, 2027; Recommendation R4 asks the Board to direct the Sheriff's Office and the County Administrator's Office to identify a methodology for reporting those full costs going forward -- meaning a $396-type figure would become the routine one, not a grand jury finding.

Report 2606's own "Request for Responses" table assigns all six findings and Recommendations R3 through R6 to the Sheriff's Office, and Finding F1 plus Recommendations R1, R2, R5, and R6 to the Board of Supervisors.▸ Under California Penal Code section 933(c), an elected officer or agency head -- the Sheriff's Office, here -- owes a written response within 60 days of the report's May 14, 2026 filing: a deadline of roughly July 13, 2026, already passed as of this piece's publication. The Board of Supervisors, on its narrower slate, gets 90 days -- a response due by roughly August 12, 2026. Neither office is required to adopt what the grand jury recommends, only to answer it on the record.